Thermoplastics are plastics that are plasticity at a certain temperature, solidify after cool down, and can repeat the process. Its molecular structure is characterized by linear macromolecular compounds, which generally do not have active groups and do not occur linear intermolecular cross-linking when heated. Thermoplastic resin molecular chain is linear or with branched-chain structure, the molecular chain between no chemical bond generation, softening flow when heated. The process of cooling and hardening is a physical change. Common thermoplastics include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyformaldehyde, polycarbonate cheese, polyamide, acrylic plastics, other polyolefins, and its copolymer, poly irony, polyphenyl ether, chlorinated polyether, and so on.
Thermoplastic properties and applications:
| Materials | Characteristics | Application |
| Acrylonitrile-butadiene-styrene (ABS) | Pros:
1. Good mechanical and thermal properties, high hardness, easy to metalize the surface 1. High fatigue resistance, stress cracking resistance, and impact strength 2. Acid and alkali resistance and other chemical corrosion 3. Lower prices5. Easy to process and shape Cons: 1. Poor weather resistance 2. Poor heat resistance |
General structural parts such as machine cover, cover, instrument housing, electric drill housing, fan impeller, radio, telephone and television housing, some electrical parts, auto parts, mechanical and conventional weapons parts |
| polypropylene
(PP) |
Pros:
1. Rigid and ductile, good bending strength, fatigue resistance, and stress-cracking resistance 2. Light 3. Maintain its mechanical properties at high temperature Cons: 1. Easy to brittle under 0 ℃ 2. Poor weather resistance |
General structural parts with poor weather resistance, such as chemical containers, pipes, sheets, pump impellers, flanges, joints, ropes, packing belts, textile equipment, electrical parts, auto parts
|
| Nylon66（PA66） | Pros:
1. Higher strength than any polyamide 2. Higher yield strength and hardness than nylon 6 and nylon 610 3. It still has high strength, toughness, rigidity, and low friction coefficient in a wide temperature range 4. Oil resistance and many chemical reagents and solvents 5. Good wear resistance Cons: 1. High moisture absorption 2. Impact strength decreases in dry environment3. The molding process is not easy to control |
Wear-resistant transmission force parts and self-lubricating parts such as a variety of gear, CAM, worm gear, shaft sleeve, bush, and other wear-resistant parts |
| polyoxymethylene(POM) | Pros:
1. Higher tensile strength than general nylon, fatigue resistance, creep resistance 2. Good dimensional stability 3. Less water absorption than nylonExcellent dielectric and elastic properties 4. Can be used in 120 ℃ is normal 5. Small friction coefficient Cons： 1. No self-extinguishing 2. High molding shrinkage |
Wear-resistant transmission force parts and anti-friction self-lubricating parts such as various gears, bearings, bushing, cage, automobile, agricultural machinery, plumbing parts |
| Polycarbonate (PC)
|
Pros:
1. High impact strength and good creep resistance 2. Good heat resistance, low brittle temperature (130 ℃) can resist sunlight, rain, and the influence of the temperature change 3. Good dimensional stability and chemical properties, high transparency 4. Good dielectric properties Cons: 1. Poor solvent resistance 2. Stress cracking 3. Long-term immersion in boiling water is easy to hydrolyze 4. Poor fatigue strength |
General structural parts such as the use of a wide temperature range of instrument housing, aircraft, automotive, electronic industry parts, textile coils, carburetors, timer parts, helmets, impact-resistant aviation glass, etc. It is also often used in everyday products |
| Polyphenylene ether(PPO) | Pros:
1. Excellent comprehensive performance, excellent water vapor resistance and dimensional stability, and excellent electrical insulation performance 2. The hardness is higher than nylon, polycarbonate, and polyformaldehyde, and the creep is smaller has little effect on acid and base Cons: 1. Poor molding liquidity 2. High price |
Used for wet, load, and electrical insulation of special fields such as electronic instruments, automobiles, mechanical equipment parts |
| Polyphenyl sulfide (PPS) | Pros:
1. Long-term use of temperature above 180 ℃ 2. Good chemical resistance, similar to PTFE 3. Special rigidity 4. Generally, drying is not required during processing Cons: 1. The poor toughness 2. Low impact strength 3. Unstable melt viscosityPros: |
Self-lubricating parts: used for electrical materials, structural materials, anti-corrosion materials. As electrical components, the consumption accounts for about 60% |
| Plastic compound(ABS+PC) | 1. Excellent ultraviolet resistance
2. Good impact strength 3. Excellent molding performance 4. High temperature (80 ~ 120 ℃) Flame retardant |
General structural parts: thin wall and complex shape products such as used in automotive internal and external parts, computer and interface equipment, communication equipment, home appliances |
