Many products involve thermoplastics. It is a smart alternative to metal parts in most industries. However, thermoplastics is also a large field. You may want to know the exact differences when choosing the specific materials in product designing.
First let’s divide thermoplastics into two parts: amorphous and semi-crystalline.
Q: Who are amorphous plastics?
A: ABS, PS, PMMA, PPO/PPE, PETG, PC, PSU, PVC, PPSU, PEI
Q: Who are semi-crystalline plastics?
A: POM, HDPE, LDPE, Nylon, PBT, PEEK, PET, PP, PPS, PTFE, UHMW-PE
General Properties of Thermoplastics
Amorphous thermoplastics are:
✓Infusible, gradually softened, and fluidized in a wide range of heating temperature;
✓Lower in density;
✓Easier to process;
✓Easier to adhere through adhesives or solvent;
✓More ductile and more tenacious;
✓Used in structural parts, rather than bearing parts or wear-resistant parts (e.g. bearings).
Semi-crystalline thermoplastic are:
✓Infused at a certain temperature, instantly fluidized when being heated to the fusion point;
✓Higher in density, tensile strength, and modulus;
✓Higher in the contraction rate of injection molding;
✓Harder to crack under stress;
✓Better at organic-chemical resistance;
✓Better at creep and fatigue resistance;
✓Suitable for not only structural parts but also bearing parts and wear-resistant parts.
Now let’s start comparing these plastic materials in specific properties: