General plastic refers to a kind of plastic products with arge output, low prices, wide end use and extensive influence. Varieties are polyethylene, polypropylene, PVC, PTFE, polystyrene, etc. It is used widely in plenty of applications, such as chemical industry, mechanical appliance, electric power and transportation.
Engineering plastics are a group of plastic materials that have better mechanical and/or thermal properties than the more widely used commodity plastics. Engineering plastics usually has a unique combination of properties that may make it the material of choice for some application. Other properties exhibited by various grades of engineering plastics include heat resistance, mechanical strength, rigidity, chemical stability and fire safety. Engineering plastics have gradually replaced traditional engineering materials such as wood or metal in many applications. Besides equalling or surpassing them in weight/strength and other properties, engineering plastics are much easier to manufacture, especially in complicated shapes.
Thermoplastic elastomers (TPE), sometimes referred to as thermoplastic rubbers, are a class of copolymers or a physical mix of polymers (usually a plastic and a rubber) which consist of materials with both thermoplastic and elastomeric properties. Thermoplastic elastomers show advantages typical of both rubbery materials and plastic materials. They have the potential to be recyclable since they can be molded, extruded and reused like plastics. They also require little or no compounding, with no need to add reinforcing agents, stabilizers or cure systems. These materials find large application in the automotive sector and in household appliances sector.
Thermosetting plastics are polymer materials which are liquid or malleable at low temperatures, but which change irreversibly to become hard at high temperatures. They are prepolymers in a soft solid or viscous state that changes irreversibly into an infusible, insoluble polymer network by curing. Thermosetting plastics are generally stronger than thermoplastic materials due to the three-dimensional network of bonds (cross-linking), and are also better suited to high-temperature applications up to the decomposition temperature.