Common classification of plastic
Are many kinds of plastic, so far put into production in the world there are about more than 300 kinds of plastic. Classification of plastic are more commonly used in two ways:
1, according to the different nature of plastic after heating divided into thermoplastic and thermoset plastics
The molecular structure of thermoplastics are linear structure, soften or melt when heated, plastic made of a certain shape, cooling after hardening. In the heat again to a certain degree of softening, cooling after hardening, this process can be repeated several times. Such as PVC, polyethylene, polystyrene and so on. Thermoplastic molding process is relatively simple to continuous production, and has very high mechanical strength, it has developed rapidly.
The molecular structure of thermosetting plastic body structure, occurs when the heat softening of a certain shape can be made of plastic, but to a certain degree of heat or by adding a small amount of curing agent, after the hardening of stereotypes, and then change the heating does not become soft the shape of the. Thermoset Plastic molding, the heat will not soften, it can not be recycled, such as phenolics, amino plastics, epoxy resin plastics and so on belong to this category. Thermosetting plastics molding process is relatively complicated, so continuous production of certain difficulties, but the heat is good, not easy to deformation, but also relatively inexpensive.
2, according to the use of plastic divided into general-purpose plastics and engineering plastics
GE Plastics is the large output, low price and wide application of plastics, mainly including polyolefins, PVC, polystyrene, phenolics, and amino-five varieties of plastics. People’s daily lives are used in many of the products made by GE Plastics.
Engineering plastics are available as engineering structural materials and parts to replace metal fabrication machinery such as plastic. For example, polyamide, polycarbonate, polyoxymethylene, ABS resin, PTFE, polyester, polysulfone, polyimide, etc.. Engineering Plastics has a low density, high chemical stability, good mechanical properties, electrical insulation is superior, easy molding processing characteristics, are widely used in automobile, electrical appliances, chemicals, machinery, apparatus, instruments and other industries, also used in Astronauts, rocket , missiles and so on.