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DESCRIPTION
ThermoplasticsTRANSCRIPT
THERMOPLASTICS
Its Properties and Applications
SKMM 2713 Manufacturing Process
By Kenneth Chaw (A13KM0053)
THERMOPLASTICS• A type of polymers
• Branched chain polymer – obtained by addition or condensation polymerization
• Can be heated and formed & reheat and reform repeatedly - Recyclable
• Heating – Softened & Melted
• Cooling – Shape formed & Solidified.
• Shape of polymer molecules :1) Linear 2) Branched
Advantages & Disadvantages of using Thermoplastics
Advantage DisadvantageProcessing is easy to be monitored – only a physical transformation
Temperature rise causes the modulus retention decreases
Do not release gases or water vapour when drying
Creep and relaxation behavior is poorer than thermosetting plastics
The wastes are partially reusable
Start deformation when exposed to organic solvents
General Characteristics• Ductile
• High fracture energy
• More easily repaired than thermosets
• Good environmental resistance
• High melt viscosities
• No chemistry during fabrication
• Potential for recycling
• Indefinite shelf life
• Anisotropic
Partially Crystallin
eNearly linear
polymer structure
Tend to be flexible and folded up to form crystal
areas
High shrinkage : opaque, good
chemical resistance, low
friction good wear resistance
Amorphous
Bulkier molecular polymer structure
Tend to be stiffer, will not fold up to
form crystals
Low shrinkage : good
transparency, high friction, low wear
and chemical resistance
Classifications of Thermoplastics
Properties and Application Table of Thermoplastics
Thermoplastic Properties ApplicationsPolypropylene (PP) Good chemical resistance Packaging, Containers
Polyethylene (PE – LDPE & HDPE)
Good chemical resistance, flexible or semi rigid. Weatherproof, good low temperature performance, non toxic and low cost.
Low Density – Packaging and containersHigh Density – Kitchenware, chemical drums
Nylon/ Polyamide (PA) Rigid, tough, hardwearing Gears, automotive- bonet part, power tool housing.
Acetal (POM) Springlike, good wear, Aerosol valves, clock parts, computer printer components
Polyvinyl Chloride (PVC) Rigid or flexible grades, weatherprooof, non-flammable, good impact strength and electrical insulation
Drainpipes and guttering, cable insulation, flooring, roofing, hosepipes
Crystalline materials
Thermoplastic Properties ApplicationsPolycarbonate (PC) Transparent, Rigid, good
weather resistance and dimensional stability
Crash helmet visors, car head lamp lenses, safety helmets, babies bottles.
Acrylic (PMMA) Rigid, clear, glossy, good weather resistance
Lenses, signs, light diffusers, point of purchase displays
Acrylonitrile Butadiene Styrene (ABS)
Rigid, opaque, tough, good gloss, texture possible, high impact strength
Computer casing, car chasis (automotive industry)
Polystyrene (PS) Brittle, transparent, poor UV stability
Toys, packaging, cosmetic packaging, refrigerator linings
Properties and Application Table of ThermoplasticsAmorphous materials