Engineering plastics are plastics that can be used as engineering materials and to replace metals. It requires excellent mechanical function, heat resistance and dimensional stability. The main ones are polyoxymethylene, polyamide, polycarbonate, ABS plastic and so on. For example, the mechanics and mechanical functions of polyoxymethylene are similar to those of copper and zinc. It is used as a bearing on a car, and its service life is twice as long as that of metal. It can also be used as other spare parts. Another example is polycarbonate, which can not only replace some metals, but also replace glass, wood, and alloys. It can be used to make various instrument shells, bicycle frames, airplane windshields, and furniture.

(1) Polyamide (nylon)

Polyamide is applied thermoplastic engineering plastics. It is a long-chain polymer compound composed of many units with an amide group () structure. For example, nylon-66, which is polycondensed from adipic acid and hexamethylene diamine, has the structural formula

Because polyamide has light weight, excellent mechanical strength, wear resistance and good corrosion resistance, it is widely used to replace copper and other metals in the manufacture of bearings, gears, pump blades and other industries in machinery, chemical, surface, and car industries. Other parts. Polyamide has high strength after melt-spun filament, and it is mainly used as synthetic fiber and can be used as medical suture.