Soften on heating and can be remoulded.
Thermoplastics soften on heating and harden on cooling reversibly, so can be remelted and recycled: PE, PP, PVC, PS, PC, PMMA, nylon, PEEK. Amorphous ones are transparent; semi-crystalline are tougher and chemical resistant. Properties fall with temperature and time (creep).
Acrylic (PMMA) is used instead of glass in windows and lenses.
Thermoplastics can be remelted and reshaped, which allows recycling and fast moulding processes such as injection moulding.
Soften on heating and can be remoulded.
Thermoplastics can be remelted and reshaped, which allows recycling and fast moulding processes such as injection moulding.
It softens and flows when it reaches its melting range or glass transition, and it hardens again on cooling.
They lose stiffness at high temperature and can creep under sustained load, so they are not suitable for very hot parts.
Typical applications include injection-moulding a housing from polypropylene, recycling PET bottles by melting them down and welding two plastic pipes by heating their ends.
Study "Polymerisation" first (topic 39 of 100 in Materials & Chemical). It covers the groundwork this topic builds on.
Melt flow index. HDT. Engineering vs commodity.
Acrylic (PMMA) is used instead of glass in windows and lenses.
The next topic is "Thermosets", which builds directly on this one.
It is classed as Intermediate in Materials & Chemical (topic 40 of 100). It is an intermediate topic. Work through the beginner topics in Materials & Chemical first.
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