EFFECT OF FLAME RETARDANT ADDITIVES IN FLAME RETARDANT

GRADE OF ABS

Thesis submitted to

COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY

In partial fulfillment of the requirements

For the degree of

MASTER OF SCIENCE

IN

BIOPOLYMER SCIENCE

By

ARJUN K GOPI

(Reg.No. 93214004)

Under the guidance of

Mr. P.V Muralidhar, Assistant manager, QA,

Bhansali Engineering Polymers Limited, Abu Road

Centre for Bio-Polymer Science and Technology (CBPST)

(A unit of CIPET)

JNM Campus, Eloor,

Udyogamandal P.O., Kochi - 683 501.

August 2015

Page | 1

Letter Head

CERTIFICATE

It is certified that the work contained in the thesis titled “EFFECT OF FLAME

RETARDANT ADDITIVES IN FLAME RETARDANT GRADE OF ABS” by

ARJUN K GOPI, (Reg.No.93214004 ) student of Centre for Bio-Polymer Science and

Technology (CBPST), ( A unit of CIPET), Kochi has been carried out under my/our

supervision , in partial fulfillment of the requirements for the degree of Master of

Science in Biopolymer Science. No part of the work reported in this thesis has been

presented for the award of any degree from any other institution.

Signature of

Supervisor(s)

Name(s)

Designation (s)

Department(s)

Place

Date

Page | 2

CERTIFICATE

This is to certify that the project entitled “EFFECT OF FLAME RETARDANT

ADDITIVES IN FLAME RETARDANT GRADE OF ABS” is an authentic record of the

project work done by ARJUN K GOPI, (Reg No: 93214004) under the supervision

and guidance of Mr. P.V Muralidhar, Assistant manager, QA, Bhansali

Engineering Polymers Limited, In partial fulfilment of the requirements for the

Degree of MASTER OF SCIENCE IN BIOPOLYMER SCIENCE.

Place:

Date: Signature of Training In-Charge

Principal

Submitted to viva-voce examination held on…………………………… at C.B.P.S.T , Eloor

Examiners:

1.

2.

Page | 3

DECLARATION

I hereby declare that the work presented in this thesis entitled “EFFECT OF FLAME

RETARDANT ADDITIVES IN FLAME RETARDANT GRADE OF ABS” is based on the

original research work carried out by me under the guidance and supervision of

Mr. P.V Muralidhar, Assistant manager, QA, Bhansali Engineering Polymers

Limited and no part of the work reported in this thesis has been presented for the

award of any degree from any other institution.

Place

Date ARJUN K GOPI

Page | 4

Acknowledgements

Though only my name appears on the cover of this project thesis, a great many

people have contributed to its production. I owe my gratitude to all those people who

have made this thesis possible and because of whom my graduate experience has

been one that I will cherish forever.

Foremost, I would like to express my sincere

gratitude to Mr. K.A Rajesh, Seniour Lecturer, CBPST, Kochi for introducing this

study to me. His guidance helped me in all the time of research and writing of this

thesis. I could not have imagined having a better advisor and mentor for my project.

I am highly obliged to Mr. S. Ranghavendra Prasad, Seniour GM (HR), Bhansali

Engineering Polymers Limited for granting me permission to do my work in this

prestigious organization. I wish to express my deep sense of gratitude and sincere

thanks to Mr. Biren Kapadia, Seniour Vice president (Manufacturing), Bhansali

Engineering Polymers Limited, Abu Road, for providing me an in-commensurable

opportunity and facilities to do my project in the organization.

I also thank my internal guide Mr. P.V Muralidhar, Assistant manager,

QA, Bhansali Engineering Polymers Limited, who provided me an endless support,

encouragement and suggestions in various stages of the development of this project. I

wish to express profound gratitude towards Mr. Amit Singh, officer R&D Bhansali

Engineering Polymers Limited, who was extremely helpful and gave their valuable

advice, guidance, suggestions and then to interest to make this project success.

It is a great pleasure to express my sincere gratitude to Dr. T O Vargheese, Assistant

professor & in-charge HLC CBPST Kochi, (A Unit of Cipet) for granting me the

permission to do enabling me to complete the work.

Most importantly, none of this would have been possible without my course in-charge,

Dr. Syed Amanualla, I would like to express my heart-felt gratitude to my Course

in-charge.

Last but not least, I would like to thank god for providing me with the abilty to

complete the graduate program. My family, friends, especially Saneesh V.S, for all

their support and love, without them I would not be able to do anything.

Page | 5

Abstract

In this study the effect of flame retardants in flame retardant grade of abs is

compared with natural ABS grade. ABS is a flammable material. It is easily burn with

high flammability value. ABS materials without flame retardant are easily burned

with a luminous yellow flame, smoking strongly and continue to burn after removal

of the ignition source. So for some particular applications we are incorporating flame

retardants into ABS. But the addition of flame retardants may leads to variation in

properties. For that I have done several physical, thermal, and rheological tests to

investigate the properties of the respective ABS grades. The results obtained was

very interesting.

ABS is commonly used in electronic housings, auto parts, consumer products, pipe

fittings, waste pipes, computer housings (electroplated on the inside), and

automotive interior and exterior trim. ABS is considered superior for its hardness,

gloss, toughness, and electrical insulation properties. Although ABS plastics are used

primarily for their mechanical properties, they also have good electrical properties

that are fairly constant over a wide range of frequencies.

Page | 6

TABLE OF CONTENTS

List of Figures............................................................................................................................9

List of Tables……………………………………………..…………………….………………………………………….……..10

CERTIFICATE…………………………………………………………………………………………………………………………1

DECLARATION………………………………………………………………………………………………………………………3

ACKNOWLEDGEMENTS…………………………………………………………………………………………………...….4

ABSTRACT……………………………………………………………………………………………………………………….……5

CHAPTER 1

INTRODUCTION, SCOPE AND OBJECTIVE………………………………………………………………………11

1.1 INTRODUCTION………………………………..........................................................................11

1.1.1 Why it is used.................................................................................................11

1.2 SCOPE AND OBJECTIVE ………………………………………………….......................................12

CHAPTER-2

LITERATURE REVIEW…………………………………………………………………………………………………….13

2.1 Acrylonitrile Butadiene Styrene (ABS Polymers)…………………………………………………..13

2.1.1 General Introduction and Historical Background………………………………………..…13

2.1.2 Chemistry and Manufacturing………………………………………………………………………14

2.1.2.1 Chemistry…………………………………………………………………………………………........14

2.1.2.2 Manufacturing…………………………………………………………………………………………15

2.1.2.2.1 Emulsion Technology…………………………………………………………………………..15

2.1.2.2.2 The emulsion-mass procedure to prepare ABS polymer………………………15

2.1.3 Mechanical Properties………………………………………………………………………………….17

2.1.4 Thermal Properties……………………………………………………………………………………….17

2.1.5 Flammability…………………………………………………………………………………………………18

2.1.6 Processing…………………………………………………………………………………………………….18

2.1.6.1 Preheating and Predrying…………………………………………………………………………18

2.1.6.2 Extrusion………………………………………………………………………………………………….18

Page | 7

2.1.6.3 Injection Moulding…………………………………………………………………………………..19

2.1.6.4 Advantages and Disadvantages……………………………………………………………..…19

2.1.6.5 Applications…………………………………………………………………………………………..…20

2.2 Flame Retardant…………………………………………………………………………………………………..21

2.2.1 What are flame retardants?..............................................................................21

2.2.2 Why do we need flame retardants?..................................................................21

2.2.3 What are the benefits of flame retardants?.....................................................21

2.2.4 Does the presence of flame retardants increase the toxicity of smoke?.........22

2.2.5 How does a fire develop?.................................................................................23

2.2.6 Most effective chemical action of flame retardants………………………………………24

2.2.7 What are the main families of flame retardants?.............................................25

2.2.7.1 Brominated Flame Retardants (BFRs)……………………………………………………….26

2.2.7.2 Phosphorous flame retardants…………………………………………………………………26

2.2.7.3 Nitrogen flame retardant…………………………………………………………………………27

2.2.7.4 Intumescent coatings……………………………………………………………………………….27

2.2.7.5 Mineral flame retardants…………………………………………………………………………28

2.2.7.6 Halogen-free Flame Retardants……………………………………………………………..…28

2.2.7.7 Other Flame Retardants - Borates, & Stannates……………………………………….29

CHAPTER-3

METHODOLOGY……………………………………………………………………………………………………………32

3.1 Materials……………………………………………………………………………………………………………..32

3.2 Material Formulation…………………………………………………………………..………………………34

3.3 Preparation of material………………………………………………………………………………………..34

3.3.1 Dry blending………………………………………………………………………………………………….34

3.3.2 Extrusion…………………………………………………………………………………………………….…34

3.3.3 Injection Moulding………………………………………………………………………………………..35

Page | 8

CHAPTER-4

EXPERIMENTAL WORK………………………………………………………………………………………………….36

4.1 Testing and Analysis Procedure…………………………………………………………………………..36

4.1.1 Pendulum Impact Test………………………………………………………………………………….36

4.1.2 Flexural test………………………………………………………………………………………………….37

4.1.3 Flammability test………………………………………………………………………………………….37

4.1.4 Heat Deflection Temperature (HDT)……………………………………………………………..38

4.1.5 Melt Flow Index (MFI)………………………………………………………………………………….38

4.1.6 Specific gravity test………………………………………………………………………………………38

4.1.7 Tensile test…………………………………………………………………………………………………..39

4.1.8 Rockwell hardness test…………………………………………………………………………………39

CHAPTER-5

RESULT AND DISCUSSION……………………………………………………………………………………………..40

5.1 Comparison between ABSTRON IM11B & ABSTRON AN450M (FR)……………………..40

5.1.1 ABSTRON AN450M (FR grade)………………………………………………………………………40

5.1.2 ABSTRON IM11B (Normal grade)………………………………………………………………….41

5.1.3 Table description………………………………………………………………………………………….42

CHAPTER-6

CONCLUSIONS AND RECOMMENDATIONS……………………………………………………………………44

6.1 Overall conclusion………………………………………………………………………………….……………44

6.2 Recommendations………………………………………………………………………………………………44

REFERENCES……………………………………………………………………………………………………………………….45

APPENDIX…………………………………………………………………………………………………………………………..49

Page | 9

List of Figures

CHAPTER 2

Figure 2.1: Engineered plastics demand, 2001 (Freedonia Industry Study, 2002)……………….13

Figure 2.2 : Emulsion ABS polymerization process………………………………………………………………15

Figure 2.3 : Major property trade-offs for ABS with increasing rubber level………………………16

Figure: 2.4 Fire Triangle………………………………………………………………………………………………………23

Figure 2.5: the fire cycle……………………………………………………………………………………………………..25

CHAPTER 3

Figure 3.1 : Mould for Injection moulding specimen…………………………………………………………..35

CHAPTER 4

Figure 4.1 : Impact tester……………………………………………………………………………………………………36

Figure 4.2: Dimension measurement for Izod type test specimen………………………………………37

Figure 4.3: Flexural tester……………………………………………………………………………………………………37

Figure 4.4: Flammability……………………………………………………………………………………………………..37

Figure 4.5: HDT…………………………………………………………………………………………………………………..38

Figure 4.6: MFI……………………………………………………………………………………………………………………38

Figure 4.7: Specific Gravity………………………………………………………………………………………………….38

Figure 4.8 : UTM…………………………………………………………………………………………………………………39

Figure 4.9: Hardness tester…………………………………………………………………………………………………39

APPENDIX

Figure A1: Global consumption of Flame retardants..............................................................49

Figure A2: Future Trends and Innovation................................................................................50

Page | 10

List of Tables

CHAPTER 2

Table 2.1: Effect of molecular characteristics of the elastomer phase and SAN copolymer

forming the matrix……………………………………………………………………………………………………………..16

CHAPTER 3

Table 3.1: Typical properties of ABS (injection moulding grade)…………………………………………32

Table 3.2: Types, trade name, manufacturer and purpose of material for ABS…………………..32

Table 3.3: Types, trade name, manufacturer and purpose of materials for additives………….33

Table 3.4: Material Formulation…………………………………………………………………………………………34

Table 3.5: Injection moulding operation condition……………………………………………………………..35

CHAPTER 5

Table 5.1: properties of ABSTRON AN450M (FR grade)………………………………………………..…... 40

Table 5.2: Properties of ABSTRON IM11B (Normal grade)…………………………………………………..41

CHAPTER 6

Table 6.1: Recommended Fire retardants…………………………………………………………………………..44

APPENDIX

Table A1: Material testing data...............................................................................................51

Page | 11

CHAPTER-1

INTRODUCTION, SCOPE AND OBJECTIVE

1.1 INTRODUCTION

Flame retardants are chemicals which are added to combustible materials to render them

more resistant to ignition. They are designed to minimise the risk of a fire starting in case of

contact with a small heat source such as a cigarette, candle or an electrical fault. If the flame

retarded material or an adjacent material has ignited, the flame retardant will slow down

combustion and often prevent the fire from spreading to other items.

Since the term “flame retardant” describes a function and not a

chemical class, there is a wide range of different chemicals which are used for this purpose.

Often they are applied in combinations. This variety of products is necessary, because the

materials and products which are to be rendered fire safe are very different in nature and

composition. For example, plastics have a wide range of mechanical and chemical properties

and differ in combustion behaviour. Therefore, they need to be matched to the appropriate

flame retardants in order to retain key material functionalities.

1.1.1 Why it is used?

Plastics are synthetic organic materials with high carbon and high hydrogen content, they

are combustible. Flame retardants are added to polyolefins, polycarbonate, polyamides,

polyester, and other polymers to increase resistance to ignition, reduce flame spread,

suppress smoke formation, and prevent a polymer from dripping. A combustible plastic

material does not become non-combustible by incorporation of a flame retardant additive.

However, the flame retardant polymer resists ignition for a longer time, takes more time to

burn, and generates less heat compared to the unmodified plastic. The primary goal is to

delay the ignition and burning of materials, allowing people more time to escape the

affected area.

A significant change in flame retarding standards regarding the evolution of smoke as an

additional requirement is emerging and is being addressed by new materials and

formulations. Many traditional flame retardants increase smoke evolution as they suppress

flame propagation. New materials are being developed to balance flame retarding efficacy

and smoke generation. Nano clays are currently mostly used in combination with already

existing flame retardant chemistries to meet commercial flame retardant specifications and

pass tests. However, it is clear that the opportunity exists for such a technology to change

the landscape of flame retardant products in the near future.

Page | 12

1.2 SCOPE AND OBJECTIVE

The purpose of this project was to study the function of flame retardants in polymer.

Flame retardant systems are intended to inhibit or to stop the polymer combustion

process.

In function of their nature, flame retardant systems can either act physically (by

cooling, formation of a protective layer or fuel dilution) or chemically (reaction in the

condensed or gas phase).

They can interfere with the various processes involved in polymer combustion

(heating, pyrolysis, ignition, propagation of thermal degradation).

A mixer, single screw extruder and injection moulding were used for sample

preparation. The types of the testing and analysis are as follows:

(a) Mechanical Properties

Two types of mechanical properties were conducted, that is Pendulum Izod impact

and flexural test. Pendulum Izod impact was used to determine the impact strength

of ABS sample. Flexural test was also carried out to determine the stiffness of the

ABS specimen.

(b) Flammability

Oxygen Index Test was used to determine the flammability properties of the

polymer.

(c) Thermal Properties

Heat defection temperature (HDT) was used to determine the temperature at which

it loss the rigidity.

(d) Material Characterization Test

MFI (Melt Flow Index) test was conducted to obtain the melt flow rate and to

determine the processibility of the ABS material.

Page | 13

CHAPTER-2

LITERATURE REVIEW

2.1 Acrylonitrile Butadiene Styrene (ABS Polymers)

2.1.1 General Introduction and Historical Background

The name ABS polymer is derived from the initial letters of three main monomers –

acrylonitrile, butadiene and styrene, used in its preparation. ABS is not a random terpolymer

of acrylonitrile, butadiene and styrene. Industrially important ABS polymers are two-phase

polymer systems that consist of dispersed polybutadiene (or a butadiene copolymer) rubber

particles and a matrix of styrene- acrylonitrile copolymer (SAN). The rubber particle is

grafted with styrene and acrylonitrile to enhance their compatibility with the matrix.

The fraction of rubber content in ABS is varies from 10-25% for common commercial grades

and special grades, e.g. for blending with poly(vinyl chloride) can even contain over 45%

rubber. The higher rubber content and the different type of polymer forming the continuous

phase result in the ABS polymers having a number of properties better than common grades

of high-impact polystyrenes.

Introduced commercially in the 1940s, ABS is a polymer whose sales have grown over the

years to become the largest engineering thermoplastic in the world. In 1982, the

consumption of ABS polymer in the individual Western countries varied from 0.3 to1.5kg

per person. In the U.S. alone, sales in 1989 exceeded 1.2 billion pounds. Demand in the U.S.

for engineered plastic is projected to advance four percent per year through 2006 to 1.6

billion pounds, valued at $3.11 billion. The demand for engineering thermoplastics in the

year of 2001 is shown at Figure 2.1, with ABS has the largest consumption rate (28.8%)

compare with the others.

Figure 2.1: Engineered plastics demand, 2001 (Freedonia Industry Study, 2002)

Page | 14

2.1.2 Chemistry and Manufacturing

ABS consists of two phases, a continuous phase of styrene-acrylonitrile (SAN) copolymer,

and a dispersed phase of grafted polybutadiene particles. Each of these phases contributes

unique characteristics to the polymer.

2.1.2.1 Chemistry

Each of the three monomers, acrylonitrile, butadiene, and styrene, is important component

of ABS. The fundamental repeating unit of the ABS chain is:

Common types of ABS polymers have an average composition of 21 to 27% acrylonitrile, 12

to 25% butadiene and 54 to 63% styrene. Acrylonitrile primarily offers chemical resistance

and heat stability; butadiene delivers toughness and impact strength; and the styrene

component provides ABS with balance of clarity, rigidity, and ease of processing.

Styrene and acrylonitrile can be copolymerized to form SAN copolymers, typically at a 70/30

ratio of S/AN. Like polystyrene, SAN is a clear copolymer, but with the additional

characteristics of higher chemical resistance, better surface hardness, and improved

toughness. This copolymer is a commercially significant product, with major applications in

markets such as battery cases, disposable cigarette lighters, and house wares.

ABS polymer systems typically contain between 70 and 90% SAN. In forming the continuous

phases of the ABS, the SAN contributes its characteristics of easy processing, high strength,

and rigidity, chemical resistance, and good surface hardness and appearance. The second

phase of the two-phase ABS system is composed of dispersed polybutadiene (rubber)

particles, which are grafted on their surface with a layer of SAN. The layer of SAN at the

interface forms a strong bond between the two phases, which allows the polybutadiene

rubber to add toughness to the ABS system, forming a rigid, impact resistant product. The

rubber phase is typically present in the range of 10-30%.

Manipulations of the two phases produce the range of polymer characteristics seen in the

different ABS products. The major variables of the SAN phase are the acrylonitrile level and

molecular weight. The rubber level can be varied to adjust the impact strength of the

polymer. Resin properties are also strongly affected by the rubber particle size distribution,

the molecular weight, and cross-link density of the rubber as well as by the molecular

weight, composition, and level of the SAN graft on the rubber particle surface. Normally,

ABS with high rigidity has higher styrene content. Super high impact ABS possesses higher

composition of butadiene if compare to medium impact ABS.

Page | 15

2.1.2.2 Manufacturing

ABS polymers can be prepared by mechanical blending of the individual components or by

grafted polymerization of a mixture of styrene with acrylonitrile in the presence of suitable

rubber component. There are three commercial polymerization processes for

manufacturing ABS: emulsion, suspension and bulk. The most common technique for

producing the grafted polybutadiene phase is emulsion polymerization.

2.1.2.2.1 Emulsion Technology

It is possible to produce the final product in a single step by grafting in emulsion. A typical

commercial emulsion process is shown in Figure 2.2. It involves five steps: rubber

polymerization, agglomeration, grafted polymerization, polymer recovery and

compounding.

Figure 2.2: Emulsion ABS polymerization process

2.1.2.2.2 The emulsion-mass procedure to prepare ABS polymer:-

First, part of the styrene and acrylonitrile are grafted onto the polybutadiene in emulsion.

The latex particles are then extracted into a newly added monomer mixture in the presence

of a coagulant. After separation of the aqueous phase, the partially grafted polybutadiene

forms a stable dispersion in the styrene- acrylonitrile mixture. Further polymerization is a

continuous mass process; the first stage (up to conversion of 40 to 70%) is carried out in a

stirred autoclave and the next stage in a tower plug-flow reactor. The heat of reaction is

removed by a cooling jacket. The polymerization is maintained at the boiling point. The

unreacted monomers are removed in the evacuated zone of the extruder.

The properties of ABS polymers are strongly affected by the molecular characteristics of

both the elastomers phase and the SAN copolymer forming the matrix.

Page | 16

Table 2.1 summarized the effects, which will occur under some situations. The properties of

this multi-phase system are also affected by conditions at the interface between the rubber

and the thermoplastic matrix. The effect of rubber level is extremely important, and the

major trade-offs from increased rubber level are shown in Figure 2.3. ABS polymer has low

density (1020 to 1060 kgm-3) and the bulk density of the pellets is also low, usually 500 to

600 kgm-3. The material is opaque as a result of the different refractive indices of the two

phases. The presence of the polar nitrile group results in certain affinity of the ABS polymer

for water or water vapour. An increase in the humidity content will lead to complications in

processing and to deterioration in some properties.

Table 2.1: Effect of molecular characteristics of the elastomer phase and SAN copolymer forming the

matrix

Figure 2.3: Major property trade-offs for ABS with increasing rubber level.

Page | 17

2.1.3 Mechanical Properties

The overall toughness offered by ABS materials is the prime mechanical property that

prompts most users to select ABS for their applications. The standard measure of impact

strength used for ABS is notched Izod impact strength, as measured by ASTM D256 A.

Depending on its impact strength, material is classified as very high, high or medium impact

polymer. As pointed out previously, its value determines in which class of standard product

a material belongs. Although ABS is notch sensitive, it is much less so than many other

polymers, including polycarbonate and nylon. In addition to good impact strength at room

temperature, ABS retains significant impact strength at very low temperatures. This has led

to the use of ABS in critical low temperature applications. ABS materials can deform in a

ductile manner over a broad temperature range and at high strain rates. This deformation is

accompanied by a significant whitening of the specimen resulting from craze formation and

separation of the rubber phase from the matrix polymer.

Another important characteristic of engineering thermoplastics is their stress- strain

behaviour in flexure. Such measurements are usually made using a simple supported beam

test specimen loaded at mid span according to ASTM D790. As with tensile properties, the

flexural strength at yield and flexural modulus can be used to determine the resistance of a

product to short-term loadings. They are also useful in comparing the strength and rigidity

of the many ABS products.

For many applications, multiaxial impact strength, typically measured using a falling or

driven dart, is as important as Izod impact strength. Reporting of multiaxial impact strength

is not yet common practice; however, data is now available from manufacturers for many

products. Although the two types of tests do not directly correlate, products demonstrating

high Izod impact strength in general demonstrate high multiaxial impact strength. Neither of

these impact tests produce information that is mathematically applicable to design. The

anticipated level of abuse a product will see in a particular application, combined with the

designer's experience, will determine the impact class selected.

The Rockwell hardness (RH) of products is useful in comparing the ability of the surface of a

part molded from different products to resist becoming blemished by intermittent loads.

The specific gravity of different standard ABS products does not very much. However, it

does vary significantly for many of the specialty grades and alloys.

2.1.4 Thermal Properties

The critical thermal properties for ABS are heat distortion, coefficient of linear thermal

expansion, thermal endurance, thermal conductivity, and specific heat. The most common

measure of heat distortion is the deflection temperature under load as measured by ASTM

D648. High-heat ABS, ABS/polycarbonate (PC) alloys, and ABS/styrene-maleic anhydride

(SMA) alloys all extend applications of ABS into the temperature up to 110oC at 1.8 MPa for

short-term exposures.

In general, plastics have significantly higher thermal expansion co-efficient than metals.

Consequently, in applications where parts are constrained, thermal stresses must be

Page | 18

accommodated in part design or expansion may induce failure in the part. This property is

especially important in ABS products designed for electroplating.

The thermal properties of ABS polymers are characterized mainly by the glass transition

temperature, Tg. An increase in temperature of the material leads to a decrease in the

tensile strength and an increase in the ductility and toughness. However the modulus of

elasticity in tension decreases.

2.1.5 Flammability

Basically, ABS has a low LOI index with a range of 17-18 %. ABS materials without flame

retardant are easily burned with a luminous yellow flame, smoking strongly and continue to

burn after removal of the ignition source. The high impact ABS will has a smell of burnt

rubber.

ABS grades that meet various standards for flammability performance are available. The

non-flame retardant (FR) general-purpose grades are generally classified as UL 94 HB

according to Underwriters' Laboratories Test Method UL94, and also meet Motor Vehicle

Safety Standard 302. These grades are used in applications having a reduced fire risk. For

applications requiring higher degrees of flame retardancy, ABS grades have been developed

based on alloys with PVC or through an additive approach using halogen in combination

with antimony oxide. Included among the FR grades are materials that meet the

Underwriters' UL94 V0 requirements beginning at a minimum thickness of 1.47 mm.

2.1.6 Processing

ABS material can be processed by injection molding, extrusion, blow molding or calendaring.

However, injection molding and extrusion account for more than 93 % of all ABS material

usage. ABS polymers process very easily and can be fabricated into very complex parts. ABS

requires significantly lower processing temperatures and is less sensitive to processing

conditions.

2.1.6.1 Preheating and Predrying

ABS materials are hygroscopic, and have an equilibrium moisture content of 0.3-0.4 % at

23°C and 50 % relative humidity. While mechanical properties in the finished part are not

greatly affected by this moisture, its presence during processing can affect the part

appearance greatly. Maximum moisture levels of 0.2 % are suitable for injection molding

and maximum levels of 0.03 % are suitable for extrusion of ABS materials. These moisture

levels can be reached by drying the material prior to processing in a dehumidified air drier

for 2 to 3 hours.

2.1.6.2 Extrusion

An extruder with a minimum L/D ratio of 24:1 is recommended to ensure a uniform mixing

and melt temperature over the die. A screen pack consisting of a 20- 40 mesh combination

is recommended. Single or two-stage screws are suitable. However, the latter part is

preferred since it also aids in devolatilization and results in an improved extrudate quality.

Page | 19

2.1.6.3 Injection Moulding

ABS polymers can be processed in all types of injection molding equipment, but optimum

results are obtained with reciprocating screw machines since it provides more uniform melt

and higher available pressure. Processing temperatures range from 177 to 288°C, depending

on the specific grade. Injection pressure of 69- 138 MPa and clamp pressure of 281-422

kg/cm2 of projected part surface are usually sufficient. Screw having a length to diameter

(L/D) ratio of 20:1 are recommended.

2.1.6.4 Advantages and Disadvantages

ABS, being copolymerized from three different monomers, has high impact strength and

competes well with polypropylene, although it is more expensive. Its dimensional stability is

good; it replaces die-cast metal components and can be electroplated. ABS is excellent for

vacuum forming and blow moulding for the production of articles such as fire extinguishers,

bus wheel arches, industrial containers, refrigerator shells and protective helmets. Basically,

ABS is preferred for its favorable balance of strength, toughness, high gloss, colorability,

processability and price. The balances of properties which are exhibited by ABS are not

found in any other plastics material. Specialist applications can be tailor made by

adjustment of the proportions and arrangement of the three parts of the copolymer, thus

emphasizing the character of the components. Besides the advantages, the material has

also a number of limitations. The disadvantages are as follows:

1) Limited chemical resistance to hydrocarbon and concentrated acids and alkalis.

2) It is mostly opaque.

3) Electrical properties are not outstanding; however, they are adequate for most purpose.

4) It is easily burn with high flammability value.

Specialty Grades

High Heat Grades: High-heat grades of ABS are produced by increasing the molecular

weight, and the acrylonitrile content, while reducing the total rubber present. Most recent

work has employed an additive approach.

These products have property balances similar to those of standard ABS except for

significantly improved heat resistance. They are somewhat more difficult to process because

of the higher melt viscosity, and they are relatively expensive. Alloys of ABS with styrene-

maleic anhydride (ABS/SMA) offer similar property balances with a lower melt viscosity at a

similar cost.

Chemical Resistance: One of the advantages of ABS relative to reinforced polyolefins and

high impact polystyrene is its chemical resistance. The polar nitrite groups make ABS quite

resistant to a variety of solvents and uptake of water is relatively low (<1 %). This chemical

Page | 20

resistance has allowed ABS entry into a wide variety of home appliances and some

automotive areas.

Flame Retardant Grades: Standard grades of ABS are considered slow burning polymers,

and most meet Underwriters Laboratories requirements for a UL94 HB rating. ABS can be

modified using halogenated additives to meet more stringent flammability requirements.

These flame retardant grades offer a balance of properties similar to medium-impact

standard ABS grades. Grades with high flexural modulus or with improved light stability are

also offered. Many ABS/PVC alloys also meet these flammability requirements. These grades

are important for electrical housing applications and contribute to a significant fraction of

ABS usage. Halogenated and phosphorus additives are generally used as flame retardants,

though halogenated styrene can be copolymerised into the ABS.

Clear ABS: Clear ABS is a transparent ABS material, which the basis is the matching of the

refractive indices of each of the rubber core, graft and matrix phases. Clear ABS grades use

methyl methacrylate as a fourth monomer to match the refractive indices of the other

monomers. The process is complicated by the fact that the refractive indices have to match

over the temperature range of use, so that the change in refractive index with temperature

must also match. Properties are similar to those of medium-impact standard ABS grades.

Plating Grades: ABS can be electroplated in the same process used for metals after being

prepared via a preplate system, which etches the surface using chromic acid and deposits an

electroless layer of copper or nickel, rendering the surface conductive. ABS also lends itself

to plating. Such grades are commonly used in car mirrors, headlight bezels and faucets

(taps). Chrome plated ABS faucets can be made in styles that cannot be made in metal.

These products also offer a relatively low coefficient of linear thermal expansion which

reduces stresses between the metal plate and the ABS during exposure to extremes in

temperature.

Filled ABS: A filled ABS has a higher strength, rigidity, modulus and high temperature

dimensional stability by adding glass fiber and is suitable for stressed structural applications.

This filled ABS is commonly used is in skis and applications in the automotive industry such

as car dashboard supports. Stainless steel filled ABS can be used when more effective

shielding from electromagnetic interference is required.

2.1.6.5 Applications

ABS's light weight and ability to be injection molded and extruded make it useful in

manufacturing products such as drain-waste-vent (DWV) pipe systems, musical instruments

(recorders, plastic clarinets, and piano movements), golf club heads (because of its

good shock absorbance), automotive trim components, automotive bumper bars, medical

devices for blood access, enclosures for electrical and electronic assemblies,

protective headgear, whitewater canoes, buffer edging for furniture and joinery panels,

luggage and protective carrying cases, small kitchen appliances, and toys,

including Lego and Kre-O bricks. Household and consumer goods are the major applications

of ABS. Keyboard keycaps are commonly made out of ABS. ABS plastic ground down to an

Page | 21

average diameter of less than 1 micrometre is used as the colorant in some tattoo inks.

Tattoo inks that use ABS are extremely vivid.

2.2 Flame Retardant

2.2.1 What are flame retardants?

Flame retardants are chemicals which are added to combustible materials to render them

more resistant to ignition. They are designed to minimise the risk of a fire starting in case of

contact with a small heat source such as a cigarette, candle or an electrical fault. If the flame

retarded material or an adjacent material has ignited, the flame retardant will slow down

combustion and often prevent the fire from spreading to other items. Since the term “flame

retardant” describes a function and not a chemical class, there is a wide range of different

chemicals which are used for this purpose. Often they are applied in combinations. This

variety of products is necessary, because the materials and products which are to be

rendered fire safe are very different in nature and composition. For example, plastics have a

wide range of mechanical and chemical properties and differ in combustion behaviour.

Therefore, they need to be matched to the appropriate flame retardants in order to retain

key material functionalities. Flame retardants are thus necessary to ensure the fire safety of

a wide range of materials including plastics, foam and fibre insulation materials, and foams

in furniture, mattresses, and wood products, natural and man-made textiles. These

materials are e.g. used in parts of electrical equipment, cars, airplanes and building

components.

2.2.2 Why do we need flame retardants?

Both our homes and offices contain an increasing potential "fire load" of flammable

materials because of the development of electrical and electronic equipment, and of rising

levels of comfort (furniture, carpets, toys, magazines and papers ...). The potential causes of

fires also tend to increase, especially in electronic equipment where the accelerating

processor power, electronic sophistication but at the same time miniaturisation, result in a

concentration of energy and an increase in risks of local overheating or other electrical fire

risks. Flame retardants can prevent an increase in fire risk from the growing number of

consumer and electronic goods in homes and offices. Flame retardants protect modern

materials such as technical plastics, building insulation, circuit boards and cables from

igniting and from spreading a fire.

2.2.3 What are the benefits of flame retardants?

Most people do not realise that their television set, sofa, mattress and computer are all

made essentially from plastics (originally made from crude oil), and without the inclusion of

flame retardants many of these products can be set alight by just a short circuit or cigarette

Page | 22

and become a burning mass in just a few minutes. Did you know for example, that a regular

TV set contains in its combustible plastics an energy content which is equivalent to several

litres of petrol? Flame retardants can be applied to many different flammable materials to

prevent a fire or to delay its start and propagation by interrupting or hindering the

combustion process. They thus protect lives, property and the environment. Flame

retardants contribute to meeting high fire safety requirements for combustible materials

and finished products prescribed in regulations and tests. Although fire safety can be

achieved by using non-combustible materials in some cases or by design and engineering

approaches, the use of flame retarded materials often meets the functionality and aesthetic

requirements of the consumer as well as offering the most economical approach.

2.2.4 Does the presence of flame retardants increase the toxicity of smoke?

This is a concern which is often raised. It is based on the fact that some flame retardants act

by impeding the combustion reactions in the gas phase and therefore lead to incomplete

combustion which in turn means a smoky fire. However, large scale studies have

demonstrated that the toxic hazards from a fire are more dependent on how much is

burning under which conditions of temperature and ventilation rather than what is burning.

Two cases can be considered:

1. The flame retarded (FR) material is subject to the primary ignition source: if this is a small

flame or other low energy source like a cigarette butt, the presence of flame retardants in

the material may cause it to smoulder and smoke somewhat, but will severely impede

ignition and in most cases no fire will develop. If burning is sustained, the release of heat

and the spread of flames will be severely hindered by flame retardants allowing people

more time to escape from the fire. The most significant reduction in toxic gases from fires is

achieved by actually preventing the fire, or preventing it from spreading from one item to a

whole room.

2. The flame retarded material is not the first item ignited but is involved in a fire that is

already developing: In this case flame retardants cannot prevent the ignition of the material

and it will eventually be thermally degraded or burn. However, flame retardants will reduce

the rate of flame spread and heat release. The impact of flame retardants on smoke or fire

gases also depends on the proportion of flame retarded material to the total fire load. Room

fire tests which compared a room with non-flame retarded materials to a room with flame

retarded items (TV cabinet, business machine housing, upholstered chair, electrical cables,

and electrical circuit board) revealed: The total quantities of toxic gases released by the FR

products was one third that for the non FR. Total smoke production was not significantly

different. "Because the total quantities of material consumed in the full room tests with FR

products are much lower than with non FR products, the total carbon monoxide [the

dominant toxic fire gas] emissions are thus around half with the flame retarded products,

significantly reducing the fire hazard."

Page | 23

Figure 2.4: Fire Triangle

2.2.5 How does a fire develop?

A fire can basically be split into three phases, the initiating fire, the fully developed fire and

the decreasing fire. The fire starts with an ignition source (for example a match) setting

combustible material (for example an upholstered armchair) on fire. The fire spreads, heats

up the surroundings and once the materials in the room have formed enough flammable

gases and are sufficiently hot, flashover takes place and the whole room is engulfed in the

fire. This is the start of the fully developed fire, where temperatures up to 1 200 °C can be

reached. The fire will later decrease as the available fire load is consumed by the fire or if

the fire occurs in a totally closed room the fire can die because of oxygen deficiency.

The fire triangle indicates where flame retardants can interfere in the combustion process.

On the one hand, there are materials that are easily ignitable but have a relatively small

energy content like paper on the other hand, there are materials which are difficult to ignite

Page | 24

but once ignited will release a large amount of energy like diesel fuel or many plastics. In

addition, in all fires secondary effects occur. These do not primarily determine the course of

the fire, but cause most of the fire deaths or damage to materials. These effects are:

Smoke development

Fire gas toxicity

Corrosivity and contamination by soot (more relevant to materials than to humans

and particularly sensitive for electronic equipment)

However, as we all know, even materials such as wood do in fact burn vigorously,

because once ignited the heat generated breaks down long-chain solid molecules into

smaller molecules which transpire as gases. The gas flame itself is maintained by the

action of high energy radicals (that is H. and OH. in the gas phase) which decompose

molecules to give free carbon which can react with oxygen in air to burn to CO2,

generating heat energy. By their chemical and/or physical action, flame retardants

prevent or even suppress the process of combustion during a particular phase of the

fire cycle. This can be either during heating, ignition, flame spread or decomposition

(pyrolysis).

2.2.6 Most effective chemical action of flame retardants

The reaction in the gas phase: where the flame retardant interrupts the radical gas phase combustion process resulting in a cooling of the system, a reduction and suppression of the supply of flammable gases.

The reaction in the condensed phase: where the flame retardant builds up a char layer, smothering the material and inhibiting the oxygen supply, thereby providing a barrier against the heat source or already ignited flame from another source.

Less effective physical action of Flame retardants can take place by

Cooling: where the additive or chemically induced release of water, cools the underlying substance to a temperature that is unable to sustain the burning process.

Coating: where the substance is shielded with either a solid or gaseous layer, protecting it against the heat and oxygen required for combustion to take place.

Dilution: Chemically inactive substances and additives turn into non-combustible gases which dilute the fuel in the solid and gaseous phases of the fire cycle.

Page | 25

Figure 2.5: the fire cycle

The Fire Cycle

Any energy source (heat, incandescent material or a small flame) can be the initial

ignition source (1). Energy transmitted by the ignition source to the polymer creates a degradation

where pyrolysis takes place (2). Which are emitted to the gas phase. In the condensed phase, the result is an inert

carbonized material, called char (3). Pyrolysis is a process that degrades the polymer’s long-chain molecules into smaller

hydrocarbon molecules, the flammable gases (4) In the gas phase, flammable gases are mixed with oxygen from the air. The proper

mix of oxygen and fuel is reached in the combustion zone (5), where hundreds of exothermic chemical reactions take place involving high-energy free radicals (e.g. H.

and OH.), fuel and oxygen. A perfect combustion would theoretically produce H2O and CO2. In real life,

incomplete combustion products are also emitted during a fire (CO, PAHs, HCN, etc) (6).

Energy (7) emitted during exothermic reactions is transmitted to the polymer and

reinforces pyrolysis. This allowing the reaction to sustain itself.

2.2.7 What are the main families of flame retardants?

The main families of flame retardants are based on compounds containing:

Halogens (Bromine and Chlorine) Phosphorus Nitrogen Intumescent Systems

Page | 26

Minerals (based on aluminium and magnesium) Halogen Free Flame retardants Others (like Borax, Sb2O3, nanocomposites)

2.2.7.1 Brominated Flame Retardants (BFRs)

BFRs are commonly used to prevent fires in electronics and electrical equipment. This area accounts for more than 50% of their applications for example in the outer housings of TV sets and computer monitors. Indeed, the internal circuitry of such devices can heat up and, over time, collect dust. Short circuits and electrical or electronic malfunctions can occur. Printed circuit boards also require flame retardancy properties which are often provided by a cross-linked brominated epoxy resin polymer manufactured from tetrabromobisphenol-A (TBBPA). In addition, BFRs are used in wire and cable compounds, for example for use in buildings and vehicles as well as other building materials, such as insulation foams.

Bromine, like chlorine, fluorine and iodine is one of the elements in the chemical group known as halogens. The word halogen is derived from Greek meaning ‘salt-former’; because these elements are commonly found in nature reacted with metals to form salts.

The effectiveness of brominated flame retardants lies in their ability to release active bromine atoms (called low-energy free radicals) into the gas phase before the material reaches its ignition temperature

These bromine atoms effectively quench the chemical reactions occurring in the flame, reducing the heat generated and slowing (or even preventing) the burning process; thus preventing the fire cycle being established or sustaining itself.

Brominated flame retardants dehydrogenate polymers by virtue of abstracting hydrogen atoms needed to produce hydrogen bromide. This process enhances charring of the polymer on expense of volatile combustible products. This contributes to the flame retardancy of the polymer.

Often and when permitted, the addition of metallic compounds such as zinc or antimony oxides will enhance the efficiency of BFRs, by allowing the formation of transition species, so called metal Oxo halides, which allow the deposit of a protective layer of metal oxides.

2.2.7.2 Phosphorous flame retardants

The class of Phosphorus-containing flame retardants covers a wide range of inorganic and organic compounds and include both reactive (chemically bound into the material) and additive (integrated into the material by physical misering only) compounds. They have a broad application field, and a good fire safety performance.

The most important phosphorus-containing flame retardants are:

Phosphate esters Phosphonates and phosphinates Red phosphorus and ammonium polyphosphate

Page | 27

When heated, the phosphorus reacts to give a polymeric form of phosphoric acid. This acid causes the material to char, forming a glassy layer, and so inhibiting the “pyrolysis” process (break down and release of flammable gases), which is necessary to feed flames. By this mode of action the amount of fuel produced is significantly diminished, because char rather than combustible gas is formed.

The intumescent char plays a specific role in the flame retardant process. It acts as a two-way barrier, both hindering the passage of the combustible gases and molten polymer towards the flame and shielding the polymer from the heat of the flame.

Phosphorous flame retardants are thus able to offer specific performance properties, depending on the required fire performance, processing conditions and mechanical properties of the material. Certain products contain both phosphorus and chlorine, bromine or nitrogen, thus combining the different flame retarding mechanisms of these elements. They are widely used in standard and engineering plastics, polyurethane foams, thermosets, back coating and textiles.

2.2.7.3 Nitrogen flame retardant

Three chemical groups can be distinguished: pure melamine, melamine derivatives, i.e. salts with organic or inorganic acids such as boric acid, cyanuric acid, phosphoric acid or pyro/poly-phosphoric acid, and melamine homologues such as melam, melem and melon, the latter finding only experimental use at this stage. Nitrogen flame retardants are believed to act by several mechanisms: In the condensed phase, melamine is transformed into cross-linked structures which promote char formation. Ammonia is released in these reactions. In conjunction with phosphorus, the nitrogen appears to enhance the attachment of the phosphorus to the polymer. A mechanism in the gas phase may be the release of molecular nitrogen which dilutes the volatile polymer decomposition products.

2.2.7.4 Intumescent coatings

Intumescent coatings are fire protection systems which are used to protect materials such as wood or plastic from fire (prevent burning), but also to protect steel and other materials from the high temperatures of fires (thus preventing or retarding structural damage during fires). The coatings are made of a combination of products, applied to the surface like a paint, which are designed to expand to form an insulating and fire resistant covering when subject to heat.

The products involved contain a number of essential interdependent components:

spumific compounds, which (when heated) release large quantities of non-flammable gas (such as nitrogen, ammonia, CO2)

a binder, which (when heated) melts to give a thick liquid, thus trapping the released gas in bubbles and producing a thick layer of froth

An acid source and a carbon compound. On heating, the acid source releases phosphoric, boric, or sulphuric acid, which chars the carbon compound (mechanism described under phosphorus flame retardants above) causing the layer of bubbles to

Page | 28

harden and producing a fire resistant barrier. Often the binder can also serve as the carbon compound.

2.2.7.5 Mineral flame retardants

Aluminium trihydroxide (ATH) is by far the most widely used flame retardant on a tonnage basis. It is inexpensive, but usually requires higher loadings in polymers up to more than 60%, because the flame retardant mechanism is based on the release of water which cools and dilutes the flame zone. Magnesium hydroxide (MDH) is used in polymers which have higher processing temperatures, because it is stable up to temperatures of around 300°C versus ATH which decomposes around 200 °C. Other inorganic fillers like talcum or chalk (calcium carbonate) are not flame retardants in the common sense; however, simply by diluting the combustible polymer they reduce its flammability and fire load. Fine precipitated ATH and MDH (< 2 µm) are used in melt compounding and extrusion of thermoplastics like cable PVC or polyolefins for cables. For use in cable, ATH and more often MDH are coated with organic materials to improve their compatibility with the polymer. Coarser ground and air separated grades can be used in liquid resin compounding of thermosets for electrical applications, seats, panels and vehicle parts.

2.2.7.6 Halogen-free Flame Retardants

Most halogen-free flame retardants have an environmentally friendly profile, which means that they pose no harm to the environment and do not bio-accumulate in biota. In addition they have a low (eco) toxicity profile and will eventually mineralize in nature. Due to these characteristics, none of the halogen-free flame retardants are considered to be PBT or vPvB.

Metal phosphinates: These are well suited for glass fibre reinforced polyamides and polyesters and are added at levels of about 20 % – often combined with N-synergists. Key aspects are a high phosphorus content (> 23 %), no affinity to water and a good thermal stability (up to 320 °C) which make them compatible with lead free soldering operations.

Inorganic Metal phosphinates are an old known chemical class recently introduced as active FR component in different proprietary synergistic blends. Used in different polymers, especially Polypropylene homo and copolymer for UL 94 V2 applications at some percent loading, gives very high GWIT on thin items. They can be used in PC, PC/ABS, PS, TPU and some engineering polymers like PBT and PA6 thanks to his very high phosphorus content in the range 20 to 40 %, thermal stability, and non-blooming characteristics.

Melamine Polyphosphate (MPP) is especially suited for glass fibre reinforced polyamide 6,6, where it is added at ca. 25 % for UL 94 V0 performance. It has a good thermal stability (ca. 300 °C). MPP is often used as synergist in combination with phosphorus FRs.

Page | 29

Melamine cyanurate (MC) is especially suited for unfilled and mineral filled polyamides. UL 94 V0 can be achieved with 10 to 15 % in unfilled PA and up to 20 % for UL 94 V2 in low glass filled PA 6. MC is often used as synergist in combination with phosphorus FRs.

Red phosphorus is a polymeric form of elemental phosphorus. It is used mainly in glass fibre reinforced PA 6,6 at 5 to 8 % addition level, where its high efficiency at low loading guarantee to maintain the excellent mechanical and electrical properties of the polymer while obtaining the highest flame proofing characteristics. Due to its inherent colour, compounds are limited to red or black colours. In addition, precautions against degradation have to be taken.

Aryl phosphates and phosphonates: their main use is styrenic blends at 10 to 20 % addition level for UL 94 V0. They are often used as co-components in FR-formulation. Their limitations are possible plastisicing effects and a certain volatility at high processing temperatures. Blooming can have a negative influence on electrical properties

Magnesium hydroxide (MDH, Mg(OH)2: high filler levels of about 45 to 50 % are necessary to reach UL 94 V0. Because of its limited temperature stability, it is mainly used in low glass fibre PA 6.

Ammonium polyphosphate in combination with nitrogen synergists can be used in polyolefins at addition levels of ca. 20 to 30 %.

2.2.7.7 Other Flame Retardants - Borates, & Stannates.

Boron containing compounds: A major application of borates is the use of mixtures of boric acids and borax as flame retardants for cellulose (cotton) and of zinc borate for PVC and other plastics like polyolefins, elastomers, polyamides, or epoxy resins. In halogen-containing systems, zinc borate is used in conjunction with antimony oxide, while in halogen-free systems, it is normally used in conjunction with aluminium trihydroxide, magnesium hydroxide, or red phosphorus. In some particular applications zinc borate can be used alone. Boron containing compounds act by stepwise release of water and formation of a glassy coating protecting the surface.

Zinc compounds were initially developed as smoke suppressants for PVC (Zinc hydroxyl stannate). Later it was found that they also act as flame retardants in certain plastics mainly by promoting char formation. Zinc sulphide shows synergistic effects in PVC and can partly substitute antimony trioxide.

Page | 30

Main flame retardants that are used by industries:-

Antimony trioxide

Chemical formula: Sb2O3

Density: 502g/cm3

Melting point: 656° C

Boiling point: 1425° C

Antimony trioxide is the organic compound with formula Sb2 O3. It is the most important

commercial compound of antimony. It is found in nature as the minerals valentinite and

senarmontite. Like most polymeric oxides, Sb2 O3 dissolves in aqueous solution with

hydrolysis.

The structure of Sb2O3 depends on the temperature of the sample. Dimeric Sb4O6 is the high

temperature (1560) gas. Sb4O6 molecules are bicyclic cages, similar to the related oxide of

phosphorus(III), phosphorus trioxide. The cage structure is retained in solid that crystallizes

in a cubic habit. The most stable form is orthorhombic, consisting of Sb-o-Sb-o chains that

are linked by oxide bridges between the Sb centers. This form is exists as in nature as the

mineral valentinite.

The main application is as flame retardant synergist in

combination with halogenated materials. The combination of halides and the antimony

being the key to the flame retardant action for polymers, helping to from less flammable

chars. Such flame retardants are found in electrical apparatus, textiles, leather, and

coatings.

Tetra bromo bisphinol A (TBBA) Chemical formula: C15H12Br4O2 Density: 2.12g/cm 3 Melting point: 178 O C Boiling point: 250 O C

Page | 31

Tetra bromo bisphinol A is a brominated flame retardant. The compound is a colorless solid, although commercial samples appear yellowish. It is one of the most common flame retardants. TBBA is mainly used as a reactive component of polymers, meaning that it is incorporated into the polymer back bone. It is used to prepare fire resistant polycarbonate by replacing some bisphenol A. A lower grade of TBBPA is used to prepare epoxy resins, used in printed circuit boards. Deca (decabromodiphenyl ether) Chemical formula: C12Br10O Density: 3.64g/cm3 Melting point: 294 to 296oC Boiling point: 425oC Decabromodiphenyl ether is a brominated flame retardant which belongs to the group of polybrominated diphenyl ethers. Deca is a flame retardant which is always used in conjunction. Antimony trioxide in polymers. Mainly in high impact polystyrene which is used in the television industry for cabinet backs. Alamark-275(dibutyl tin maleate) Chemical formula: C12H20O4Sn Molecular weight: 346.99 Melting point: 135 to 140oC Specific gravity (water) 1.36 to 1.42 Used as condensation catalyst, stabilizers for PVC resin. Dibutyl maleate has been found to impart both flame retardant synergism and uv stabilization, when used in conjunction with organo bromine flame retardant. 1, 2-Bis (2,4,6-tribromophenoxy)ethane One of the major "novel" brominated flame retardants (NBFRs) from various polymer materials. An environmental pollutant. Simple aromatic halogenated organic compounds, such as 1, 2-Bis (2, 4, 6-tribromophenoxy) ethane, are very unreactive. Reactivity generally decreases with increased degree of substitution of halogen for hydrogen atoms. Materials in this group may be incompatible with strong oxidizing and reducing agents. Also, they are incompatible with many amines, nitrides, azo/diazo compounds, alkali metals, and epoxides.

Page | 32

CHAPTER-3

METHODOLOGY

3.1 Materials

ABSTRON AN450M (injection moulding FR grade) and ABSTRON IM118 (injection moulding,

medium flow, high impact, medium rigidity) ABS were used for this study. They were

supplied by Bhansali Engineering Polymers Limited, in the form of extruded pellets. Typical

ABS properties are summarized in below table 3.1. The manufacturer has the proprietary

right on the ratio of ABS monomer. Based on information given by the manufacturer, ABS

consists of 60% styrene, 25% acrylonitrile and 15% butadiene approximately. Types, trade

name, manufacturer and applications of materials for ABS is presented in table 3.2. Six types

of additives were used in this study. There are EBS (Ethylene bis(stearamide)), calcium

stearate, Silicon oil, TBBA(Tetra bromo bisphinol A) , ATO(Antimony trioxide), OTS(dibutyl

tin maleate) . The trade name, manufacturer and purpose of materials are stated in table

3.3 below.

Table 3.1: Typical properties of ABS (injection moulding grade)

Type Trade Name Manufacturer Applications

Heat resistant ABSTRON HR59 Bhansali Engineering Polymers Limited

Remote Controller Cases, Air Cleaner Parts.

Injection Moluding ABSTRON IM11B Bhansali Engineering Polymers Limited

Printer Parts, Headphone Stereo Body, Key Board.

Flame Retardant ABSTRON AN450M Bhansali Engineering Polymers Limited

Interior Parts of Refrigerator, Exterior Parts of Room Air- Conditioner.

Table 3.2: Types, trade name, manufacturer and purpose of material for ABS

Page | 33

Table 3.3: Types, trade name, manufacturer and purpose of materials for additives

Type Trade name Manufacturer Purpose

EBS HI-LUB CMS Chemical, Indonesia.

Decreasing friction and abrasion of the polymer surface, and to contribute colour stability and polymer degradation.

CS Calcium Stearate Sunshine organic Pvt, Ltd. , India

It can act as an acid scavenger or neutralizer at concentrations up to 1000ppm, a lubricant and a release agent.

Si-Oil FLUID 100 Wacker metroark chemical Pvt. Ltd, India

Primarily used as lubricants.

TBBA FR-1524 ICL industrial Products, Bromine Compounds Ltd, Israel

It is one of the most common flame retardants. TBBA is mainly used as a reactive component of polymers, meaning that it is incorporated into the polymer back bone.

ATO XN Chemico chemical Pvt, Ltd, India

The combination of halides and the antimony being the key to the flame retardant action for polymers, helping to from less flammable chars.

OTS STS 102 SV plastochem pvt Ltd, India

Dibutyl maleate has been found to impart both flame retardant synergism and uv stabilization, when used in conjunction with organo bromine flame retardant.

Page | 34

3.2 Material Formulation

Ingredients Resin in % and additive in Phr recipe

HRG 30-33

SAN-LF 45-48

EBS(Ethylene bis(stearamide)) 0.4-0.8

CS(Calcium stearate) 0.2-0.4

Si-Oil 0.1-0.15

TBBA(Tetra bromo bisphinol A) 20-30

ATO(Antimony Trioxide) 3-7

OTS(dibutyl tin maleate) 0.2-0.6

Table 3.4: Material Formulation

3.3 Preparation of material

3.3.1 Dry blending

The correct proportion of the resin and the additives had to be weighed by using Electronic

Balance.

A Hopper Dryer Type: KET/166120, KABRA EXTRUSION TECHNIK, INDIA was used to dry the

ABS resins since ABS is a hygroscopic material which can absorb moisture up to 0.3% within

24 hours. The duration for dry blending process was 5 minutes.

3.3.2 Extrusion

The standard temperatures of the grade are set on the extruders and the attainment

of temperatures is monitored. Till attaining the temperature the functioning of the

downstream equipment’s are checked. The materials are taken from the premix silo

to the hopper of the extruder. The extruder is operated with the standard operating

guidelines. The mixed materials are extruded as per work instructions. As soon

as the materials comes out of the die holes, it goes through the water in the water

bath for quenching, passes through the air knife blower for drying, enters into the

pelletiser for cutting of the granules, passes through the double decker vibrator for

segregation of pellets as per the sizes.

Page | 35

3.3.3 Injection Moulding

Impact bars were injection moulded by using SP-80 Injection moulding machine. The

mould for injecting the test specimens is shown in Figure. The parameter of the

setting is shown in Table.

Table 3.5: Injection moulding operation condition

Figure 3.1 : Mould for Injection moulding specimen

Page | 36

CHAPTER-4

EXPERIMENTAL WORK

Flame retardants comprise a diverse group of chemicals which are widely used at relatively high concentrations in many applications, including the manufacture of electronic equipment, textiles, and plastic polymers and in the car industry, primarily to protect materials against ignition and to prevent fire-related damage. More than 175 different types of flame retardants exist, which are commonly divided into four major groups: halogenated organic (usually brominated or chlorinated), inorganic, organophosphorus and nitrogen-containing flame retardants. Depending on the mode of action, flame retardants can act at any of the steps involved in the combustion process. Flame retardants are designed to prevent the spread of fire and have thereby helped to save many lives while also dramatically reducing the economic impact of fires.

There is need for fire resistant polymers in the construction of small, enclosed spaces such as skyscrapers, boats, and airplane cabins. In these tight spaces, ability to escape in the event of a fire is compromised, increasing fire risk. In fact, some studies report that about 20% of victims of airplane crashes are killed not by the crash itself but by ensuing fires. So it is very important to test the plastic product before it reaches the market. Testing yields basic information about a Plastic, its properties relative to another material and its quality in reference to a standard. In this study I was conducted eight tests which are:-

Pendulum Izod impact test

Flexural test

Flammability

Heat defection temperature

MFI (Melt Flow Index)

Specific gravity

Tensile strength

Rockwell hardness

4.1 Testing and Analysis Procedure Figure 4.1 : Impact tester

4.1.1 Pendulum Impact Test

The impact test was done according to ASTM D 256A by using Izod impact tester, pendulum type model (the maker is CEAST) as shown in Figure. The test specimen obtained from the injection moulding, was then notched using a notching machine. The notching machine used is made by HEM. The notch depth fixed at 3 ± 0.05 mm. The impact strength is calculated by dividing the indicator reading (energy) by the cross sectional area of the specimen. The results were reported in kJ/m2 of notch for notched specimens. This test was measured at room temperature (25 ± 2°C) and 50 ± 5% relative humidity.

Page | 37

Figure 4.2: Dimension measurement for Izod type test specimen

4.1.2 Flexural test

Flexural test was carried out according to ASTM D 790. The test procedure used is Test Method 1, Procedure A, i.e., three-point loading utilizing center loading. Since the modulus was determined between small initial deflections, to ensure good accuracy, a low force load cell (100N) was used. Flexural test was carried out a simple supported beam. The distance between the spans was 100 mm and the strain rate (compression speed) was 5 mm/min. The flexural properties were measured at room temperature (25 ± 2 oC) on a Universal Testing machine (make: LLOYD instrument, Model: LRX 5K) as shown in Figure. Five samples were tested and average values were recorded.

Figure 4.3: Flexural tester

4.1.3 Flammability test

Test Method : UL-94

Specimen size : 125 x 13 x 3 mm

Conditioning : 23 ± 2ºC and 50 ± 5 R.H., 48 hrs.

Methane gas flow : 105 ml/min. with back pressure

Rate to burner : 10 mm water.

Flame height : 20 ± 1 mm

Flame calibration : 100ºC to 700ºC within 44 ± 2 sec. Figure 4.4: Flammability

Apply flame to the middle of the bottom edge for 10 sec. and remove the burner. Measure after flame time in secs - t1. Again apply the flame for another 10 secs. Measure after flame time - t2 and afterglow time - t3. Check the dripping particle ignited the cotton or not.

Page | 38

4.1.4 Heat Deflection Temperature (HDT)

Heat deflection temperature is defined as the

temperature at which a standard test bar (127 x 12.5 x 3

mm) deflects 0.25 mm. under a stated load of 1820 kPa.

This test can distinguish between those materials that

lose their rigidity over a narrow temperature range and

those that are able to sustain light at high temperature.

HDT test was carried out following ASTM D 648, with HDT

Tester 148HDD machine (Maker: Yasuda Seiki) as

illustrated in Figure 4.5. The apparatus for measuring HDT

consists of an enclose oil bath fitted with a heating

chamber and automatic heating control. A cooling system

is also incorporated. The specimens were supported on

steel supports that are 4 in. apart, with the load applied

on top of the specimen vertically and midway between

the supports. A dial indicator was used to measure

deflection. Figure 4.5: HDT

4.1.5 Melt Flow Index (MFI)

Melt flow index (MFI) of the polymer was determined according to

ASTM D1238 at 220 °C under a load of 10 kg. The equipment used

was Deven port Model: MF110. About 3 g of sample was introduced

into the barrel, at 220°C and was allowed to melt and achieve

thermal equilibrium for 5 minutes. Load of 10 kg was applied on the

melt and material was extruded through the die. The extrudates

were cut at regular interval, usually at 15 secs interval. The cut-off

extrudates were weighed and the value was converted to the unit of

g/10 min. Figure 4.6: MFI

4.1.6 Specific gravity test

Specific gravity is a measure of the ratio of mass of a given volume of material at 23°C to the

same volume of deionized water. There are two basic test procedures- Method A and

Method B. The more common being Method A, can

be used with sheet, rod, tube and molded articles.

For Method A, the specimen is weighed in air then

weighed when immersed in distilled water at 23°C

using a sinker and wire to hold the specimen

completely submerged as required. Density and

Specific Gravity are calculated.

Figure 4.7: Specific Gravity

Page | 39

4.1.7 Tensile test

Tensile strength is a measurement of the ability of a material to

withstand forces that tend to pull it apart and to determine to what

extent the material stretches before breaking. Specimens are

placed in the grips of the universal tester (Make: Instron, Model:

1011) at a specified grip separation and pulled until failure. For

ASTM D 638 the test speed is determined by the material

specification. An extensometer is used to determine elongation and

tensile modulus.

Tensile strength = Force (load)/area

Elongation = Change in length / Original length

Figure 4.8: UTM

4.1.8 Rockwell hardness test

A Rockwell hardness number is a number derived from a net increase in depth impression as

the load on an indenter is increased from a fixed minor load to a major load and then return

to minor load. Hardness test was carried out by ASTM D 785.Choose the correct scale for

the specimen under test. Rockwell hardness values are reported by a letter to indicate the

scale used and a number to indicate the reading. The Rockwell hardness scale used shall be

selected, unless otherwise noted in individual methods or specifications. Discard the first

reading after changing a ball indenter, as the indenter does not properly seat by hand

adjustment in the housing chuck. The full pressure of the major load is required to seat the

indenter shoulder into the chuck.

With the specimen in place on the anvil, turn the capstan

screw until the small pointer is at a zero position and the

large pointer is within ± 5 divisions of B 30 or the "set"

position on red scale. This adjustment applies without

shock a minor load of 10 kg, which is built into the

machine. Final adjustment of the gage to "set" is made by a

knurled ring located on some machines just below the

capstan hand wheel. If the operator should overshoot his

"set" adjustment, another trial shall be made in a different

test position of the specimen; under no circumstances

should a reading be taken when the capstan is turned

backward. Within 10 s after applying the minor load, and

immediately after the "set" position is obtained, apply the

major load by releasing the trip lever. Remove the major

load 15 (+ 1, -0) s after its application. Read the Rockwell

hardness on the red scale to the nearest full scale division

15 s after removing the major load. Record the readings.

Figure 4.9: Hardness tester

Page | 40

CHAPTER-5

RESULT AND DISCUSSION

5.1 Comparison between ABSTRON AN450M (FR) & ABSTRON IM11B

5.1.1 ABSTRON AN450M (FR grade)

Table 5.1: properties of ABSTRON AN450M (FR grade)

Tests Test condition Test method unit Typical value

Rheological Test

Melt Flow Index At 220°C/10Kg ASTM D 1238 gm/10 min 43

Mechanical tests

Izod impact, notched 3.2mm

23±2°C ASTM D 256, Method A

Kgfcm/cm 23

Izod impact notched 6.4mm

23±2°C ASTM D 256, Method A

Kgfcm/cm 19

Tensile strength, Type I, 3.2mm at yield

50mm/min ASTM D 638 K/sq.cm 445

Flexural strength, 6.4mm at yield

5mm/min ASTM D 790 Kg/sq.cm 570

Flexural modulus, 6.4mm at yield

5mm/min ASTM D 790 Kg/sq.cm 20500

Rockwell hardness

ASTM D 785 R-scale 100

Thermal tests

Heat distortion temperature, 6.4mm

At 18.5 Kg/sq.cm( annealed at 75°C/2Hr)

ASTM D 648, Method-A

°C 87

Flame class rating

Flammability, 3.0mm

UL-94 V0

Other tests

Specific gravity ASTM D 792 1.17

Mould shrinkage

ASTM D 955 % 0.40-0.60

Page | 41

5.1.2 ABSTRON IM11B (Normal grade)

Table 5.2: Properties of ABSTRON IM11B (Normal grade)

Tests Test condition Test method unit Typical value

Rheological Test

Melt Flow Index At 220°C/10Kg ASTM D 1238 gm/10 min 32

Mechanical tests

Izod impact, notched 3.2mm

23±2°C ASTM D 256, Method A

Kgfcm/cm 29

Izod impact notched 6.4mm

23±2°C ASTM D 256, Method A

Kgfcm/cm 23

Tensile strength, Type I, 3.2mm at yield

50mm/min ASTM D 638 K/sq.cm 470

Flexural strength, 6.4mm at yield

5mm/min ASTM D 790 Kg/sq.cm 630

Flexural modulus, 6.4mm at yield

5mm/min ASTM D 790 Kg/sq.cm 21500

Rockwell hardness

ASTM D 785 R-scale 106

Thermal tests

Heat distortion temperature, 6.4mm

At 18.5 Kg/sq.cm( annealed at 85°C/2Hr)

ASTM D 648, Method-A

°C 94

Flame class rating

Flammability, 3.2mm

UL-94 HB

Other tests

Specific gravity ASTM D 792 1.045

Mould shrinkage

ASTM D 955 % 0.40-0.60

Page | 42

5.1.3 Table description

The ability of a material to absorb the energy of a high-speed blow without breaking is a

property of great technological importance. Izod impact test is one of the empirical methods

of measuring impact strength in current use in the plastics industry. A pendulum striker hits

the specimen horizontally at a point above the notch. After the specimen has been

fractured, the pendulum continues on its and the energy remaining is measured by the

extent of the excess swing.

In this study I have conducted numerous tests to find out the izod impact strength. I have

done five tests for each. I have noticed that in both cases (notched 3.2mm and 6.4mm) a

lowering of impact strength from 29 to 23 Kgfcm/cm.

Tensile strength (TS) is the maximum stress that a material can withstand while being

stretched or pulled before failing or breaking. Some materials will break sharply, without

plastic deformation, in what is called a brittle failure. Others, which are more ductile,

including most metals, will experience some plastic deformation and possibly necking

before fracture. Tensile strength is defined as a stress, which is measured as force per unit

area. It is expressed in newtons per square metre (N/m²).

I have done five tests for each to find out the tensile value. There is reduction in tensile

strength from 470 to 445Kg/sq.cm

The flexural properties of materials are of considerable technical importance since

deformations involving flexure are most frequent. Usually a molded article must be

designed to maintain its shape under flexure. Therefore, flexural stiffness or modulus of

flexure is a property of considerable technical importance. Flexural strength is the ability of

the material to withstand bending forces applied perpendicular to its longitudinal axis. The

stresses induced by the flexural load are a combination of compressive and tensile stresses.

In this test also I have done five tests for each ABS grade. I came to know that both flexural

strength and flexural modulus are lowering from ABSTRON IM11B to ABSTRON AN450M.

The values are 630 & 21500 and 570 & 20500 respectively.

The Rockwell test determines the hardness by measuring the depth of penetration of an

indenter under a large load compared to the penetration made by a preload. There are

different scales, denoted by a single letter, that use different loads or indenters.

I have done the test on R-scale, I got the values of ABSTRON IM11B and ABSTRON AN450M,

which are 106 and 100 respectively.

Page | 43

The quality of material extruded through a standard orifice under specified temperature and

load, measured for 10 minutes. The test load conditions of MFI measurement is normally

expressed in kilograms rather than any other units. The method is described in the similar

standards ASTM D1238. Melt flow rate is an indirect measure of molecular weight, with high

melt flow rate corresponding to low molecular weight. At the same time, melt flow rate is a

measure of the ability of the material's melt to flow under pressure. Melt flow rate is

inversely proportional to viscosity of the melt at the conditions of the test, though it should

be borne in mind that the viscosity for any such material depends on the applied force.

Ratios between two melt flow rate values for one material at different gravimetric weights

are often used as a measure for the broadness of the molecular weight distribution.

Under 220°C temperature and 10Kg load I got two values of ABSTRON IM11B and ABSTRON

AN450M, which are 32 and 43 respectively.

Heat deflection temperature is defined as the temperature at which a standard test bar

deflects a specified distance under a load of 66psi and 264psi. It is used to determine short-

term heat resistance. It distinguishes between materials that are able to sustain light loads

at high temperatures and those that lose rigidity over a narrow temperature range. The test

specimen is loaded in three-point bending in the edgewise direction. The outer fiber stress

used for testing is either 0.455 MPa or 1.82 MPa, and the temperature is increased at

2°C/min until the specimen deflects 0.25 mm.

The values for heat distortion temperature test was 94 and 87 (under 18.56Kg/sq.cm) for

ABSTRON IM11B and ABSTRON AN450M respectively.

Flammability is the ability of a substance to burn or ignite, causing fire or combustion. The

degree of difficulty required to cause the combustion of a substance is quantified through

fire testing. Thermoplastic materials are more or less easily combustible. Efforts to develop

flame retarding plastic materials have been going along with the increasing use of

thermoplastics. As a result, flame retarding formulations are available today for all

thermoplastics which strongly reduce the probability of their burning in the initiating phase

of fire. The possibility to make plastic flame retardant secures the scope of utilization for

thermoplastics and, in fact increases their range of application.

I have conducted horizontal burning (HB) for ABSTRON IM11B at 3.2mm and vertical

burning (V0) for ABSTRON AN450M at 3.0mm

Specific gravity is the ratio of the density of a substance to the density (mass of the same

unit volume) of a reference substance.

The values for specific gravity of ABSTRON IM11B and ABSTRON AN450M are 1.045 and 1.17

respectively.

Page | 44

CHAPTER-6

CONCLUSIONS AND RECOMMENDATIONS

6.1 Overall conclusion

The main objective of this project is to study the effect of flame retardancy in a flame

retardant grade. For that I have selected two ABS grade which are ABSTRON IM11B (natural)

and ABSTRON AN450M (FR-grade). And I have conducted several tests to find out the

properties of ABS. A synergistic effect in which the impact strength of the ABSTRON IM11B

(natural) is found to be higher than ABSTRON AN450M (FR-grade). The data for ABS was

obtained from this study whereas the impact strength value of ABSTRON AN450M with

increasing content of flame retardants, the impact strength of the grade is decreased.

The HDT analysis shows that the temperature at which the materials loss rigidity decrease

slightly as the loading level of flame retardant into ABS increased. The flame retardancy of

ABS is relatively poor with natural detroite the most rapidly. The polybutadiene in ABS with

the double bond structure is a highly flammable material. From the result obtained, the

effect of flame retardant on ABSTRON AN450M shows the highest increment of flame

retardancy. The most optimum formulation in terms of cost and mechanical properties is

ABSTRON AN450M. From the properties obtained, it is proposed that this material is

suitable to produce suitcase and parts of miscellaneous goods such as computer monitor,

photocopier parts, fax machine parts, and parts of camera and printer.

6.2 Recommendations

The initial work on flammability properties has given interesting results. This method

can be further investigated by developed a correlation between LOI and smoke

density (smoke production). Char determination can also be carried out by using

DTA/TGA technique to record accurately heat and mass change. Incorporation of

flame retardant will reduce the mechanical properties of the material. In order to

minimize the reduction, compatibilizer should be added to study the effect of

coupling agents in flame retarded ABS material. Investigate the effects of

compatibilizer on flame retarded ABS material. Use higher content of flame

retardant. Incorporation of different types of flame retardant (not more than 10 phr)

into ABS such as:

Iron compounds Brominated materials

FeOOH – Bayferrox yellow 3905 (Bayer) Octabromodiphenyl oxide

Fe3O4 – ferrosoferric black iron oxide 1,2 – bistribromophenoxy ethane

FeOCl – iron (III) oxychloride Poly-dibromostyrene

Iron (III0 molybdate decabromodiphenyl ether Table 6.1: Recommended Fire retardants

Page | 45

REFERENCES

1. Adams, M. E., Buckley, D. J., Colborn, R. E., England, W. P., and Schissel, D. N. (1993).

Acrylonitrile-Butadiene-Styrene Polymers. United Kingdom: Rapra Preview Reports.

3-4.

2. Alexander H. T. (2000). Plastics Additives’ Steady Evolution. Business. 78: 21- 31.

3. Bach, H. C. and Knorr, R. S. (1989). Encyclopedia of Polymer Science and Engineering

Volume 1. John Wiley & Sons. 388-423.

4. Bair, H. E., Boyle, D. J. and Kelleher, P. G. (1980). The Effect of Light and Heat on the

Rubber Content and Impact Strength of ABS. Polymer Engineering and Science.

20(15): 995-1001.

5. Billmeyer, F. W. JR. (1984). Textbook of Polymer Science 3rd Edition. Toronto: John

Wiley& Sons. 301-345.

6. Brisimitzakis, A. C. (1994). Styrenic Resins. In Modern Plastic Magazine ed.

Encyclopedia Handbook. United States of America : McGraw-Hill, Inc. 52- 53.

7. Broutman, L. J. and Kobayashi, T. (1971). AMMRC CR 71-14, Army. Material

Mechanical Res. Ctr. Watertown, Massachussetts. In Sridharan, N. S. and Broutman,

L. J. (1982). Fracture Analysis of Acrylonitrile-Butadiene-Styrene Resins. Polymer

Engineering and Science. 22(12): 760-765.

8. Brydson, J. A. (1995). Plastics Materials Sixth Edition. Oxford : Butterworth-

Heinemann Ltd. 77.

9. Bucknall, C. B. (1977). Toughened Plastics. England: Applied Science Publishers Ltd.

90-94.

10. Bucknall, C. B. and Smith, R. R. (1965). Stress-Whitening in High-Impact Polystyrene.

Journal of Polymer. 6. 437-446.

11. Chanda. M., and Roy. S. K. (1993). Plastic Technology Handbook. New York: Marcel

Dekker, Inc. 561-566.

12. Codgell, J. F. and Hardesty, R. M. (1958). SPE Journal. 14. 25. In Norbert, M. B. ed.

(1971). Mechanical Properties of Polymers. New Jersey: Wiley Interscience. 175-222.

13. Frank, L. F. (1991). Combustibility of Plastics. New York: Van Nostrand Reinhold. 122-

179.

Page | 46

14. Freedonia Industry Study. (2002). Engineered Plastics. U.S.A: CEH Marketing

Research Report. 2-3.

15. Fried, J. R. (1995). Polymer Science and Technology. USA: Prentice Hall, Inc. 251-263.

16. GAM Report. (2000). Moulding News. World Plastic Technology 2000. 41.

17. Gao, J. G., Li, D. L., Wang, D. Y. and Yang, L. T. (2000). Rheological behaviour and

Mechanical Properties of Blends of Chlorinated Polyethylene with Poly(Acrylonitrile-

Styrene-Methyl Methacrylate). European Polymer Journal. 36: 2517-2522.

18. Glenn, B., Hilton and Cathleen, A. J. (1985). Acrylonitrile –Butadiene-Styrene. In

James, M. Margolis. ed. Engineering Thermoplastics Properties and Applications.

New York : Marcel Dekker Inc. 335-371.

19. Green, J. (1989). Flame Retardant and Smoke Suppressants. In John T. Lutz, Jr.

Thermoplastic Polymer Additives. New York: Marcel Dekker, Inc. 93-204.

20. Jenkner, H. and Köln. (1983). Flame retardants for Thermoplastics. In Gächter, R and

Müller, H. Plastics Additives Handbook. New York: Hanser Publishers. 537-540.

21. Kuryla, W. C. and Papa, A. J. ed. (1973). Flame Retardancy of Polymeric Materials

Volume 3. New York: Marcel Dekker. In Chanda. M., and Roy. S. K. (1993). Plastic

Technology Handbook. New York: Marcel Dekker, Inc. 61.

22. Landrock, A. H. (1983). Handbook of Plastics Flammability and Combustion

Toxicology. New Jerseyy: Noyes Publications. 18-26, 36-41.

23. Mitsuru, Y, Shinichi, S and Yasuji, K. (1983). Comparison of Poly(styrene,

polystyrene/Acrylonitrile), High Impact Polystyrene and

Poly(acrylonitrile/Butadiene/Styrene) with Respect to Tensile and Impact Properties.

Journal of Applied Polymer Science. 28: 2209-2216.

24. Modern Plastic Magazine. ed. (1994). Encyclopedia Handbook. USA: McGraw- Hill,

Inc. 5-6.

25. Moh Ching Oliver Chang, Benny, D., Trishna Ray-chaudhuri, Liqing L. Sun, and Russell

P. Wong. (1997). Acrylonitrile-Butadiene-Styrene (ABS) Polymers. In Olagoke Olabisi.

Handbook of Thermoplastics. New York: Marcel Dekker, Inc. 135-160.

26. Molinaro, H. ed. (1999a). Lounging Aboard Coextruded Polymers. Society of Plastic

Engineers. 55(7): 6.

Page | 47

27. Moore, E. R. ed. (1989). Encyclopedia of Polymer Science and Engineering. John

Wiley & Sons. 319-321.

28. Nelson, G. L. (1995). Fire and Polymers: An Overview. In Fire and Polymers II.

Materials and Tests for Hazard Prevention. Washington: American Chemical Society.

1-25, 65-75.

29. Owen, S. R. and Harper, J. F. (1998). Mechanical, Microscopical and Fire Retardant

Studies of ABS Polymers. Polymer Degradation and Stability. 64: 449-455.

30. Troitzsch, J. (1980). International Plastics Flammability Handbook. New York: Hanser

Publisher. 17-61.

31. Uhlmann, J. G. Oelberg, J. D., Sikkema, K. D. and Nelb, R. G. (1993). Effect of Flame

Retardant Structure and Properties on ABS Performance. Plastic Compounding. 3:

38-46.

32. U.S. Environmental Protection Agency (2005). Environmental Profiles of Chemical

Flame retardant Alternatives for Low-Density Polyurethane Foam (Report). EPA 742-

R-05-002A. Retrieved 4 April 2013.

33. "Market Study Flame Retardants 3rd ed.". Ceresana Research. Retrieved 2015-02-03.

34. Market Study Flame Retardants 2nd ed., Ceresana, 07/11

35. Hollingbery, LA; Hull TR (2010). "The Thermal Decomposition of Huntite and

Hydromagnesite". Thermochimica Acta 509 (1–2): 1–11.

doi:10.1016/j.tca.2010.06.012.

36. Hollingbery, LA; Hull TR (2010). "The Fire Retardant Behaviour of Huntite and

Hydromagnesite - A Review". Polymer Degradation and Stability 95 (12): 2213–2225.

doi:10.1016/j.polymdegradstab.2010.08.019.

37. Hollingbery, LA; Hull TR (2012). "The Fire Retardant Effects of Huntite in Natural

Mixtures with Hydromagnesite". Polymer Degradation and Stability 97 (4): 504–512.

doi:10.1016/j.polymdegradstab.2012.01.024.

38. Hollingbery, LA; Hull TR (2012). "The Thermal Decomposition of Natural Mixtures of

Huntite and Hydromagnesite". Thermochimica Acta 528: 45–52.

doi:10.1016/j.tca.2011.11.002.

39. Hull, TR; Witkowski A; Hollingbery LA (2011). "Fire Retardant Action of Mineral

Fillers". Polymer Degradation and Stability 96 (8): 1462–1469.

doi:10.1016/j.polymdegradstab.2011.05.006.

Page | 48

40. van der Veen, I; de Boer, J (2012). "Phosphorus flame retardants: Properties,

production, environmental occurrence, toxicity and analysis". Chemosphere 88 (10):

1119–1153. doi:10.1016/j.chemosphere.2012.03.067. PMID 22537891.

41. Weil, ED; Levchik, SV (2009). Flame Retardants for Plastics and Textiles: Practical

Applications. Munich: Carl Hanser Verlag. p. 97. ISBN 978-1-56990-454-1.

42. Shaw, S.; Blum, A.; Weber, R.; Kannan, K.; Rich, D.; Lucas, D.; Koshland, C.; Dobraca,

D.; Hanson, S.; Birnbaum, L. (2010). "Halogenated flame retardants: do the fire

safety benefits justify the risks?". Reviews on Environmental Health 25 (4): 261–305.

doi:10.1515/REVEH.2010.25.4.261. PMID 21268442.

43. California Department of Consumer Affairs, Bureau of Home Furnishings (2000).

Technical Bulletin 117: Requirements, test procedure and apparatus for testing the

flame retardance of resilient filling (PDF) (Report). p. 1-8.

44. "Notice of Proposed New Flammability Standards for Upholstered Furniture/Articles

Exempt from Flammability Standards". Department of Consumer Affairs, Bureau of

Electronic and Appliance Repair, Home Furnishings and Thermal Insulation.

45. "Calif. law change sparks debate over use of flame retardants in furniture". PBS

Newshour. January 1, 2014. Retrieved November 1, 2014.

46. "Low VOC Cal TB 117 Using Bio-Renewable Technologies - Rowlands, J. Polyurethane

Foam Association Conference St Petersburg, Florida USA.- May 2013".

47. "Future-Proof Natural Foams for the USDA BioPreferred Program - Rowlands, J.

Utech Conference and Exhibition, Charlotte USA. June 4th and 5th 2014".

48. Guillame, E.; Chivas, C.; Sainrat, E. (2000). Regulatory issues and flame retardant

usage in upholstered furniture in Europe (PDF) (Report). Fire Behaviour Division. p.

38-48.

49. Greenstreet Berman Ltd., "A statistical report to investigate the effectiveness of the

Furniture and Furnishings (Fire) (Safety) Regulations 1988", (December 2009). The

study was carried out for the UK Department of Business and Innovation skills (BIS).

http://www.bis.gov.uk/files/file54041.pdf

50. Babrauskas, V.; Harris, R.; Gann, R.; Levin, B.; Lee, B.; Peacock, R.; Paabo, M.; Twilley,

W.; Yoklavich, M.; Clark, H. (1988). NBS Special Publication 749: Fire hazard

comparison of fire-retarded and non-fire-retarded products (Report). National

Bureau of Standards, Center for Fire Research, Fire Measurement and Research

Division. p. 1-86.

Page | 49

APPENDIX

The global market for flame retardant chemicals was worth $4.1 billion in 2008 and a

projected $4.3 billion in 2009. It reached $6.1 billion by 2014, for a compound annual

growth rate (CAGR) of 7.0%. The global flame retardant chemicals industry used 3.2 billion

pounds of materials in 2008. This is increased to 3.4 billion pounds in 2009, and 4.3 billion

pounds in 2014, for a CAGR of 5.0%. Studies have shown that a burning room containing

flame retardant products releases 75% less heat and 33% fewer toxic gases than a room that

lacks the products.

In 2006 Pentabromodiphenyl ether and Octabromodiphenyl ether were voluntarily

withdrawn by the last major manufacturer of these chemicals (Great Lakes Chemical

Corporation, now part of Chemtura) and regulated heavily in the US by the Environmental

Protection Agency (EPA), thus ensuring that there would be no new major use of these

chemicals.

In 2012, all brominated diphenyl ethers have been voluntarily withdrawn by the main flame

retardant manufacturers and also placed under EPA regulatory control for phase-out and

banning of import or use in the US. These rules effectively eliminate the use of these flame

retardant additives in any new product sold in the US, but this flame retardant may be

present in many existing products that already contains that flame retardant. HBCD, used

mostly for expanded polystyrene foam insulation, has also been selected for phase out in

the USA and Canada.

In one year, two widely used classes of flame retardants have been voluntarily withdrawn by

the manufacturers and put under regulatory ban. This has had two major effects, one

political, and one technical. It has given companies the impetus to develop viable safer

commercial alternatives and it has emboldened non-governmental organizations (NGO) to

push for further bans.

Figure A1: Global consumption of Flame retardants

Page | 50

Future Trends and Innovation

In recent years, halogen-free flame retardants increasingly replaced conventional

halogenated flame retardants in plastics used in the E&E sector. This was due to a growing

environmental awareness of the population, legal regulations, and an equal ranking of both

types of flame retardants in terms of cost and technology.

Costs of brominated flame retardants have increased drastically, novel phosphorus-organic

flame retardants and particularly mixtures of HFFR have been developed and introduced for

various materials in E&E applications. Three types of phosphorus-organic compounds were

conceived for epoxy resins to be used in printed circuit boards. Additionally, electric cast

resins and coatings were developed to replace the traditional tetrabromobisphenol A, also

when using existing technologies. In glass fibre reinforced polyamides and polyesters of

electric components on the market, decabromodiphenylether was replaced by halogen-free

alternatives based on aluminium phosphinates and melamine salts. New oligomer

phosphoric acid esters were developed and are presently applied for electric enclosures.

Phosphorus-organic flame retardants have been introduced, as the mode of action of these

phosphorus-organic derivatives in both the condensed and the gas phase is increasingly

understood. All these halogen-free

Flame retardants are reactive systems that become part of the polymer network or

represent salts or polymer species in the form of additive flame retardants. By reaction or

by these low volatile additives, migration of the flame retardants and, hence, loss of flame

retardancy are prevented. At the same time, these additives have a sufficient thermal

stability for them to be incorporated easily in the polymers mentioned.

Based on these findings, further development work is being pursued. It is aimed at creating

synergistic systems with these substances and other additives like aluminium and

magnesium hydroxides, nitrogen compounds, silicon or sulfur compounds. Next to the

further improvement of the processability of mineral flame retardants by means of

morphology alteration or surface treatments, the synergistic use of classical mineral FRs in

sub-micron to nano size is examined and commercialized. Such synergistic systems should

require smaller amounts of flame retardants, while the remaining material properties are

hardly affected. Furthermore, major efforts are dedicated to developing halogen-free flame

retardants for polystyrene based plastics. Examples are HIPS, ABS, SAN, PS-foams, and

others.

Figure A2: Future Trends and Innovation

Page | 51

Material Testing data:-

Material Testing

Styrene 1. Purity 99.5 through GC 2. Polymer content through Spectrophotometer 3. TBC through Spectrophotometer

CAN 1. Purity 99.5 through GC 2. moisture content through KF

HRG 1. OHL at 105°C 2. Contamination

EBS Melting Point, OHL

CS Melting Point, OHL

Silicon Oil OHL, Specific gravity

DPTD Acid value & amine value

TDM Make the blend and check performance Make the blend and check performance DECA

TBBA

Sb2O3

ALAMARK

WMO OHL, Specific gravity

STERYL ALCOHOL Acid value, Specific Gravity

SAN OHL, MFR and tensile

Table A1: Material testing data