Thermoplastics – Properties and applications.pptx

7/28/2019 Thermoplastics Properties and applications.pptx

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Thermoplastics Properties and

applicationsHydrocarbon plastics

1. Ployethylene (PE) Polythene

Polymerisaion of ethene CH2=CH2

Petroleum or natural gas

Types Low density PE

High density PE (HDPE)

Characteristics

Resistant to chemicals Tough and flexible

Applications Flexible bottles, toys, packing fils, seals, bowls, buckets etc..


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2. Polypropylene (PP)

Propene CH2=CH-CH3

Similar to HDPE

Characteristics

Stiffer harder stronger

Fatigue resistence

Light weight

Chemical and thermal resistantanceApplications

Houseware, car interiors, bottle caps, extruded pipes,carpet fibres


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Hydrocarbon plastics

3. Ploystyrene(PS) 20% of all thermoplastics in commercial use

Polymerisaion of ethyl-benzene

Types

HIBS

ABS (Acryknitrile-Butadine-Styrene)

SAN (Styrene-Acrylonitrile)

Characteristics

Low cost, brittle, glassy

Easy to process, excellent moldability

Poor chemical and corrosion resistence

Applications

Packaging and insulating foams, lighting panels, egg boxes, wall tiles,battery cases


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chlorocarbon and flurocarbon polymers

4. Ployvinylchloride (PVC)

Polymerisaion of monomer vinayl chloride CH2=CHCl

Mosl widely used plastics

Types UPVC

PPVC

CPVC

Characteristics

Low cost, general purpose materials

Ordinarily rigid, made flexible with plasticizers

Good flame, electrical, chemical, oil, abrasion and weather resistence

Applications

Pipes, valves, fittings, floor tiles, wire insulations, toys


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5. Ploytetrafloro ethelene (PTFE)

Mosl widely used plastics fluorocarbon polymer

Types

PVDF

PVF

PFA

Characteristics

Chemicaly inert

Excellent electrical property

Low coeff of friction

Applications

Anti-corrosive seals, pipes and valves, bearings, non-stick coatings,high temp electronic parts


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Acrylic Materials

6. Polymethyl methacrylate(PMMA) perspex or plexiglass

Polymerisaion of monomer methyl methacrylate

Characteristics Hard rigid high impact strength

Highly transparent to light

Easily formed

Readily colured and decorative properties

Applications Camera lenses, flash lights, safety flasses, drafting equipments,

display signs


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7. Polyacrylonitrile (PAN)

Polymerisaion of monomer acrylonitrile

Characteristics Highly stable

Resistant to oils and greases

Applications Synthetic fibre manufacture


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Ployamids (or Nylons)

Polymides (PA)

Condensation reactions of amine and an organic acid

Characteristics

Good mechanical properties

Very strong and tough

Good abrasion resistence

Flexible and have high impact strength

Good resistent to most solvents and chemicals

Abosrbs water

Applications

Bearings, gears, cams, fatenings, automotive parts, bushings, electricalcomponents, fibres and robes


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Hetrochain polymers

10. Polycarbonate

Condensation of bisphenol A and carbonic acid

Characteristics Good impact resistence and ductility

Transparent and low water absorption

Low fatigue resistence

Applications Safety helmets, shields and goggles, lenses, lighting

fittings, car head lamp mouldings, sterlisable medicalcomponents


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11. Polyethylene teraphthalate (PET) polyester or PETP

Condensation of ethylene glycol and teraphathalic acid

Characteristics

High strength high stiffness thermoplastics Excellent fatique and wear strength

Can be reinforced with glass fibre

Applications

Fibres, photographic fils, recording tapes, boil-in-bag,beverage containers, soft drink bottles, electricalconnectors, parts for domestic goods, automotivecomponents


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12. Polyether ether ketone (PEEK)

13. Polyphenylene oxide (PPO)

14. Polyphenylene sulphide (PPS)15. Ployamides (PI)

16.Polyamide-imide (PAI)


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Thermosetting plastics Properties

and applications

Phenolics (Bakelites)

1.polyformaldehyde (PF)

Phenol+formoldehyde (Phenol formaldehye - PF)

Chracteristics of PFs

Hard rigid stable upto 150oC

Low thermal conductivity, good electrical insulationproperty

Good resistance to oils

Low cost

Applications

Electrical plugs, sockets, switches, telephones, handles,adhesives, coatings and laminates


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Amino

formaldehyde materials

Amino group condensed with aldehydes

1. Urea formaldehyde (UF)

Condensing urea with formaldehyde

Chracteristics of PFs Similar to phenolics

good electrical insulation property

Hard and rigid

Resistant to most chemicals

Applications Electrical devices, circuit breakers, sitches,bottele cups, saucers,

plates


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2. Melamine formaldehyde (MF)

Condensing melamine with formaldehyde

Chracteristics of PFs Similar to UF

Better resistant to heat up to 95oC

Applications Similar to UF


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Other thermosetting plastics

1. polyesters

2.Epoxides (EP)

3. Polyurethanes (PUR)


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Engineering Ceramics engineering

applications

Charateristics

Resistance to abrasive and wera

High strength and high temp

Good chemical stability

Electrical insulation characteristics

Types

Oxides, carbides, sulphides, nitrides,metalloids or intermetaallica


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1. Alumina(Al2O3)

2. Silicon Carbide (SiC)

3. Silicon nitride (Si3N4) 4.partially stabilised zirconia (PSZ)

5.sialons


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1. Alumina(Al2O3)

Aluminium oxide oldest engineering ceramic

Produced from boxite ore of aluminium

Characteristics

Excellent hardness, wear resistance and chemical inert properties

Stiffer than steels

Stronger in compression thant many hardened tool steels

Retain 50% of their room temp strength at elevated temp 1093oC

Environmental resistance

Poor thermal conductors

Low newtron absorption - ??? Alumina is blended with other ceramics such as zirconia to improve its

tensile and toughness properties


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Applications

Spark plug insulators, substrates for thedeposition of electronics micricircuits and metal

cutting tool tips Load bearing applications. Rocket nozzles, pump

impellers, pump liners, check valves,

dental and medical use restoration of teeth,

bone filler, and orthopaedic implants Military armous platings protet against missiles

fired from rifles.

Thermoplastics – Properties and applications.pptx

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