synthesis and characterization of polyacrylonitrile

SYNTHESIS AND CHARACTERIZATION OF

POLYACRYLONITRILE (PAN) AND CARBON FIBERS

Department of Polymer Engineering & TechnologyUniversity of the Punjab,

Lahore

Prof. Dr. Tahir JamilChairman

Engr. Shahzad Maqsood KhanPresenter

Polymer

PANCarbon Fiber

PRESENTATION APPROACH

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Polymer

POLYMERTHE SCIENCE AND ENGINEERING OF LARGE MOLECULES

• Long chain molecules

• long molecule made up by the repetition of

small unit called monomers BUILDIGNG BLOCK

POLYMER AT PLAY

Find Polymers in figure

POLYMER CLASSESPolymers

OrganicInorganic

Natural

Proteins, Nucleic acids, Lignins, Polysccharides, Polyisoprene, Melanin

Synthetic

PE, PS, Nylons, PET, PVC, PU, PC, PMMA, PVAC, PP, PTFE

Synthetic

Fibrous glass, Silicon Carbide, Poly(boron nitrid), Poly(sulfur nitride)

Natural

Clays, Sands, Glass, Rock-like, Ceramics, Graphite/Diamond, Silicas

Organic/Inorganic

Siloxane, Polyphosphazenes, Polyphosphate esters, Polysilanes, Sol-gel network

POLYMER-A-A-A-A-A-A-A-A- Homo Polymer

-A-B-B-A-B-A-A-B- Random Copolymer

-A-B-A-B-A-B-A-B- Alternating Copolymer

-A-A-A-A-B-B-B-B- Block Copolymer

-A-A-A-A-A-A-A-A- Graft Copolymer B-B-B-B-B-B-

POLYMER

POLYACRYLONITRILE (PAN)

IMPORTANCE OF PANHomo polymers of Polyacrylonitrile have been used as

• Fibers in hot gas filtration systems

• Outdoor awnings

• Sails for yachts

• Fiber reinforced concrete

Mostly copolymers containing Polyacrylonitrile are

used as

• Fibers to make knitted clothing, like socks and

sweaters

• Outdoor products like tents

POLYACRYLONITRILE (PAN)• In 1893 Acrylonitrile was prepared by

reacting Propylene with Ammonia

(NH3) and oxygen in the presence of

catalysts.

• PAN is a vinyl polymer and a derivative

of the acrylate family of polymers.

• It is made from acrylonitrile monomer

through suspension methods using

free-radical initiators.

POLYACRYLONITRILE (PAN)

PAN LAB SYNTHESIS• Polymerization of acrylonitrile (AN) by

redox method

• Flask or lab reactor

• Nitrogen atmosphere

• Fitted with a condenser

• Reaction medium (Dimethylsulfoxide

(DMSO) solvent or water)

PAN LAB SYNTHESIS• Emulsifier ( e.g Sodium bisulfite (SBS) )

• Initiators ( e.g Potassium Persulfate (KPS),

Azodiisobutyronitrile (AIBN), Itaconic acid (IA) )

• Time 1–3.5 hr

• Precipitation

• Filtration

• Washing ( methanol and deionized water etc)

• Drying under vacuum till a constant weight

PAN CHARACTERIZATION• FTIR (Fourier Transform Infrared Spectrophotometer)

• NMR (Neutron Magnetic Resonance)

• GPC (Gel Permeation Chromatograph)

• DSC (Differential Scanning Calorimeter)

• TGA (Thermo Gravimetric Analyzer)

• TMA (Thermo Mechanical Analyzer)

PAN CHARACTERIZATIONFTIR

R. Setnescu, S. Jipa, T. Setnescu, W. Kappel,S. Kobayashi, Z. Osawa. IR and X-ray characterization of the ferromagnetic phase of

pyrolysed polyacrylonitrile, Carbon 37, (1999) 1–6.

1H-NMR spectrum of the PAN

precursors

13C-NMR spectrum of the PAN

precursors

PAN CHARACTERIZATIONNMR

PAN CHARACTERIZATIONDSC

N. Yusof and A. F. Ismail. Preparation and characterization ofpolyacrylonitrile/acrylamide-based activatedcarbon fibers developed using a solvent-free

coagulation process, International Journal of Chemical and Environmental Engineering. 1, (2010) 79-84.

PAN CHARACTERIZATIONTGA

H. B. Sadeghi, H. A. Panahi, M. Abdouss, B. Esmaiilpour,M. N. Nezhati, E. Moniri, Z. Azizi.

Modification and Characterization of Polyacrylonitrile Fiber by Chelating Ligand for Preconcentration and Determination of Neodymium Ion in Biological and Environmental

Samples. J. APPL. POLYM. SCI. (2013) 1125-1130.

PAN CHARACTERIZATIONTMA

T. V. Sreekumar, T. Liu, B. G. Min, H. Guo, S. Kumar, R. H. Hauge, R. E. Smalley, Polyacrylonitrile Single Walled Carbon Nanotube Composite Fibres. Adv. Mater. 16, (2004)

58-61.

PAN CHARACTERIZATIONDMA

Temperature v/s Storage Modulus of PAN

Temperature v/s Tanδ of PAN

PAN CHARACTERIZATIONDMA

PAN INDUSTRIAL PRODUCTION

POLYMER SYNTHESIS PILOT PLANT DEPARTMENT OF POLYMER ENGG. PU LHR

PAN FIBER & CARBON FIBER

IMPORTANCE OF PAN FIBERPAN-based fibers eventually supplanted most

rayon-based fibers, and they still dominate the

world market. In addition to high modulus fibers,

researchers have also developed a low modulus

fiber from PAN that had extremely high tensile

strength. Used in

• Sporting goods such as golf clubs, tennis rackets,

fishing rods, and skis

• Military

• Commercial aircrafts

IMPORTANCE OF CARBON FIBER

Strength: carbon fibers tensile strength is

un-matched by any metal available

(Titanium alloys, Cr Mo, steel or Aluminum

alloys)

Weight: carbon fiber/epoxy weight per

volume is less than half that of aluminum

almost 4 times lighter than titanium

Fatigue resistance of carbon fiber

surpasses that of any other structural

material


Yield strength: carbon fiber has a very high

yield strength allowing it to flex under extreme

loading and return to its original shape

Corrosion: carbon fiber/epoxy is extremely

resistant to corrosion


Carbon fiber parts will be lighter and

stronger. Because of such properties

you find this technology used in

• Aviation

• Sports

• High-end racing and

• Snowmobiles

CARBON FIBERCarbon fibers are derived from one of the three

precursor materials

• PAN (Polyacrylonitrile fiber)

• PITCH

• Isotropic

• Mesophase

• Rayon

• Melt Spinning

• Dry Spinning

• Wet Spinning

• Wet/Dry Spinning

PAN FIBER INDUSTRIAL PRODUCTION

PAN FIBER FORMATIONPolyacrylonitrile fibers were produced by

wet-spinning.

The coagulation bath is normally

• DMSO/H2O system,

• Bath temperature is 60°C

• Bath concentration is 65% (namely,

DMSO/H2O=65/35(wt/wt))

• Bath minus stretch ratio is –10%

PAN FIBER INDUSTRIAL PRODUCTION

CARBON FIBER FORMATIONFiber changing color. The white

PAN strands at the bottom pass

through the air heated oven and

begin to darken. Quite quickly

they turn to black

CARBON FIBER INDUSTRIAL PRODUCTION

• Oxidization

• Stress graphitization of

Polyacrylonitrile based carbon fiber

• Carbonization (graphitization)

PAN FIBER INDUSTRIAL FORMATION

Oxidization

• This produces an oxidized ladder polymer

structure approximately parallel to the fiber

axis which may be regarded as the template

for the formation of the oriented carbon fiber.

• Oxidation involves heating the fibers to around

300 oC in air. This evolves hydrogen from the

fibers and adds less volatile oxygen.

• The polymer changes from a ladder to a stable

ring structure, and the fiber changes color

from white though brown to black.

PAN FIBER INDUSTRIAL FORMATION


Stress Graphitization of Polyacrylonitrile

Based Carbon Fiber

• Carbon fiber can be made by the

pyrolysis of organic polymer fiber

precursors. The strength of PAN carbon

fiber declines when heated above

1,200° C.

• Therefore increasing strength with

Young's modulus can be obtained if

stress is applied to the fiber at

graphitizing temperatures.

CARBONIZATION (GRAPHITIZATION)

• Involves heating the fibers up to 3000 oC in an inert atmosphere.

• Fibers are now nearly 100 % carbon


When we heat Polyacrylonitrile, the heat causes the cyano repeat units to form

cycles…

CARBON FIBER FORMATION CHEMISTRY

At higher temperature, carbon atoms kick off their hydrogen, and the rings become

aromatic. This polymer is a series of fused pyridine rings. This expels hydrogen gas,

and gives us a ribbon-like fused ring polymer.


When the temperature increases from 600 up to 1300 oC, the ribbons will

themselves join together to form even wider ribbons like this:


More nitrogen is

expelled and the

ribbons are really

wide, and most of

the nitrogen is

gone, leaving us

with ribbons that

are almost pure

carbon in the

graphite form.


FIBER CHARACTERIZATION• XRD (X Ray Diffraction)

• SEM (Scanning Electron Microscopy)

• DSC (Differential Scanning Calorimeter)

• TGA (Thermo Gravimetric Analyzer)

• DMA (Dynamic Mechanical Analyzer)

• UTM (Universal Testing Machine)

PAN TO CARBON FIBER CHARACTERIZATIONXRD

PAN TO CARBON FIBER CHARACTERIZATIONXRD DATA

PAN TO CARBON FIBER CHARACTERIZATIONFTIR

PAN CHARACTERIZATIONYOUNG’S MODULUS & TENSILE STRENGTH

GASES RELEASED DURING PYROLYSIS OF PAN

ELEMENTAL ANALYSIS

PAN FIBER GRADEThe Carbonization temperature will determine the grade of fiber produced:

Carbonization Temperature (oC)

to 1000 1000 - 1500 1500 - 2000 2000 +(Graphitization

)

Grade of Carbon Fiber

Low Modulus

StandardModulus

IntermediateModulus

HighModulus

Modulus of Elasticity (GPa)

to 200 200 - 250 250 - 325 325 +

CARBON FIBER GROUPINGFINAL HEAT TREATMENT TEMPERATURE

Type-I, high-heat-treatment carbon fibers (HTT)

Final heat treatment temperature > 2000C and can be

associated with high-modulus type fiber.

Type-II, intermediate-heat-treatment carbon fibers (IHT)

Final heat treatment temperature should be > = 1500C

and can be associated with high-strength type fiber.

Type-III, low-heat-treatment carbon fibers

Final heat treatment temperatures not greater than

1000C. These are low modulus and low strength materials.

CARBON FIBER FORM PAN FIBER

CARBON FIBER FROM PITCH

MECHANICAL PROPERTIES OF CARBON FIBER

OUR RESEARCH PAPER61 Journal of Pakistan Institute of Chemical Engineers Vol. XXXVII

Synthesis And Characterization of Polyacrylonitrile Copolymers

Waqar Ahmad, Shahzad Maqood Khan, Muhammad Arif Butt and Tahir Jamil*

Abstract

Polyacrylonitrile (PAN) and copolymers of PAN with monomers like MMA, BA, VA, AM,

AA, and S of varying compositions and molecular weights were prepared by emulsion

polymerization in a continuous aqueous phase in the presence of sodium lauryl sulfate

as emulsifier and potassium persulfate/ammonium persulfate as initiator. The molecular

weights were determined from the dilute solution viscosity using Mark-Houwink

equation. The chemical compositions of copolymers were characterized by FT-IR

spectroscopy.

Keywords: Polyacrylonitrile (PAN), Polymer, Emulsion polymerization, FT-IR

CONCLUSIONS OF OUR WORK• The synthesis of homo and copolymers of PAN via emulsion polymerization was

successfully achieved

• Maximum yield of 94.5 % for Polyacrylonitrile (100)

• Maximum yield of 90.2 % for P(AN-co-AM-co- MAA, 96.1:3.2:0.7)

• The highest molecular weight, Mv = 144068, for copolymer P(AN-co-AM-co-

MAA, 96.1:3.2:0.7)

• followed by Mv = 75403.85 for P(AN-MMA, 96:4)

• and Mv = 75403.69 for PAN (100).

• MMA was found to be the best monomer for copolymerization of AN.

CONCLUSIONS OF OUR WORK• As commercially available PAN precursor for carbon fiber have molecular weight

about 150000 and we have achieved 144068 MW for P(AN-co- AM-co-MAA,

96.1:3.2:0.7), this sample of PAN can be a very suitable precursor for carbon

fiber.

ACKNOWLEGMENTWe are grateful to

• Prof. Dr. Arshad Chughtai (Chairman, Department of Textile Engineering & Technology University of

the Punjab Lahore

• Miss. Nafisa Gull (Research Officer, Department of Polymer Engineering & Technology University of

the Punjab Lahore)

• Dr. Misbah Sultan (Assistant Professor, Department of Polymer Engineering & Technology

University of the Punjab Lahore)

• Engr. Muhammad Shafiq, Engr. Aneela Sabir (Lecturer, Department of Polymer Engineering &

Technology University of the Punjab Lahore)

• Miss Saba Bahzad Khan (Lab Supervisor, Department of Polymer Engineering & Technology

University of the Punjab Lahore)

• Engr, Adnan Ahmed, Engr. Muhammad Azeem Munawar, Engr. Khurram Javed, Miss Sidra Waheed

(Research Technician, Department of Polymer Engineering & Technology University of the Punjab

Lahore)

THANKS FOR YOUR ATTENTION !

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synthesis and characterization of polyacrylonitrile

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