Thermoplastics vs. Thermosets
A thermoplastic is a polymeric material or plastic that becomes soft and formable when heated and rigid when cooled. This process may be repeated a number of times without chemically altering the material.
A thermoset is a polymeric material that undergoes irreversible chemical changes when it is cured through heat, catalysts, or ultraviolet light: cross-linking prevents movement of molecular chains after curing. Once cured, the structure cannot be altered.
| THERMOPLASTICS | THERMOSETS |
| Pros | Pros |
| High Impact Strength | Easy to process and laminate |
| Attractive Surface Finish | Does not necessarily need pressure or heat to form |
| Recyclable / Scrap is Reusable | Typically inexpensive |
| No Emissions | Typically stronger than thermoplastics |
| Can bond to other thermoplastics | Better suited to higher temperatures than thermoplastics |
| Can be molded or shaped by reheating | |
| Cons | Cons |
| Typically will soften with heat | Often release emissions known as volatile organic compounds (VOCs) |
| More difficult to prototype | Non-recyclable and cannot be reclaimed easily |
| Short workable pot life, with some exceptions |
| THERMOPLASTIC Materials | ||
| Name | Properties | Applications and Uses |
| Acetal | Extremely rigid, high melting point, high strength, good frictional properties, resistance to fatigue | Gears, bearings, bushings, cams, housings, conveyors, plumbing fixtures, gas tank caps, automotive door handles, seat belt components, and zippers |
| Acrylics | Exceptional resistance to long-term exposure to sunlight and weathering, outstanding clarity, good light transmission | Swimming pools, skylights, sinks, washbasins, room dividers, and the tail lights on automobiles |
| Acrylonitrile-Butadiene-Styrene (ABS) | Outstanding impact strength and high mechanical strength, great as a substrate for metalizing | Appliances, automotive parts, pipe, business machines, telephone components, shower heads, door handles, faucet handles, and automotive front grilles |
| Nylon | Known for their stability and adaptability | Automotive parts, electrical and electronic applications, and packaging |
| Polyamide-Imide | Exceptional mechanical, thermal and chemical resistant properties | Aerospace, heavy equipment, and automotive |
| Polyarylates | Known for its strength, toughness, chemical resistance, and high melting points | Automotive, appliances, electrical and electronic applications, ovenware, and outdoor lighting |
| Polybutylene | Known for high flexibility, resistance to creep, resistance to cracking, and chemical resistance | Pipe and packaging film |
| Polycarbonate | Excellent electrical insulating characteristics, strong, and rigid | Appliances, and electrical and electronic applications |
| Polyethylene | Available in a range of flexibilities and properties, rigid, and moisture resistant | Packaging films, house wares, toys, containers, pipes, drums, gasoline tanks, and coatings |
| Polyketones | Resistant to solvents and has great mechanical properties | Appliances, industrial applications, electrical and electronic applications, automotive applications, bearings, gears, hoses, and tubing |
| Polyphenylene Oxide, Modified | Low moisture absorption levels, good electrical properties over a wide range of humidity and temperature ranges, resistant to most chemicals | Electrical and electronic applications, appliances, automotive parts, business machine parts |
| Polyphenylene Sulfide | Excellent heat resistance, as well as outstanding chemical resistance, high stiffness and good retention of mechanical properties at elevated temperatures | Electrical and electronic applications, and automotive parts |
| Polypropylene | Outstanding physical, chemical, mechanical, thermal and electrical properties, light in weight, excellent resistance to staining, organic solvents, and degreasing agents, resistance to electrolytic attack, low moisture absorption rate | Dishwashing safe food containers, packaging, automotive, and appliances |
| Polystyrene | Light-weight material, about 95% air and has very good insulation properties | Packaging and foodservice products, automotive parts, toys, house wares, appliance parts, wall tiles, radio and TV housings, furniture, floats, and luggage |
| Styrene Acrylonitrile | Good chemical resistance, high heat resistance, great clarity, good dimensional stability, and high rigidity | Automobile instrument panels and interior trim and house wares |
| Sulfone Polymers | heat-resistant, can be molded to tight tolerances, exhibit low creep, excellent oxidation resistance, and compressive strength | Electrical and electronic applications and automotive parts |
| Thermoplastic Polyester (Saturated) | Highly crystalline, hard, strong and extremely tough | X-ray film, magnetic tape (audio, video and computer); packaging; metalized film, strapping and labels |
| Thermoset Materials | ||
| Name | Properties | Applications and Uses |
| Alkyds | Excellent heat resistance, dimensionally stable under components,excellent dielectric strength | Electrical applications like circuit breaker insulation, switchgear, cases, housings, capacitor and resistor encapsulation, automotive parts, and coatings |
| BMC (Bulk Molding Compound) | Highly rigid, impact resistant, exceptional physical and aesthetic properties, high strength-to-weight ratio | Appliance parts, electric and electrical components, HVAC components, industrial light housings, automotive, recessed lighting baffles |
| Diallyl Phthalate (DAP) | Virtually no post-mold shrinkage, high impact resistance, resistant to sudden and extreme jolts and severe stresses, recommended for very high temperatures, chemical resistant, fungus resistant | Cross-linking agent, thermosetting molding powders, casting resins, and laminates, military, electronic components |
| Epoxy | Provide heightened strength, electrical and chemical properties, and heat resistance | Adhesives, protective coatings in appliances, industrial equipment, aircraft components, pipes, tanks, pressure vessels, tooling jigs, and tooling fixtures |
| Melamine-Formaldehyde | Extreme hardness, excellent colorability properties, and arc-resistant non-tracking characteristics. | Rugged dinnerware, household goods, various electrical applications, bonding, adhesives, and coatings |
| Phenolic | Excellent dielectric strength, great mechanical strength and dimensional stability, resistant to high heat, wear resistant, low moisture absorption, can be machined easily | Adhesives, casting resins, laminating resins, electrical and electronic Applications, automotive, appliance handles, frac balls, and knobs |
| Polyimides | Known for thermal stability, good chemical resistance, excellent mechanical properties, exhibit very low creep and high tensile strength, inherently resistant to flame combustion, most carry a UL rating of VTM-0 | Electronics, medical tubing, adhesives, gears, covers, bushings, piston rings, and valve seats |
| SMC (Sheet Molding Compound) | Very high volume production ability, excellent part reproducibility, and it is cost effective. | Electrical applications, corrosion resistant needs, structural components at low cost, automotive, and transit |
| Thermoset Polyester | Low cost, high strength-to-weight ratio, stability, great retention of physical properties at high temperatures | Appliance parts, electric and electrical components, HVAC components, industrial light housings, automotive, recessed lighting baffles |
| Urea-Formaldehyde | Very hard, scratch-resistant material with good chemical resistance, electrical qualities, and heat resistance | Electrical and electronic products, decorative products, laminates, and chemically resistant coatings |