olyethylene, the smaller the index is, the larger the molecular weight and the higher the mechanical strength, although the fluidity is lower The low heat resistance and the inactive chemical property of polyethylene result in bad nd bondin The substance can be used to manufacture all kinds of bottles, fishnet, ropes, cables, telephone wire stringing, chopping boards as well as dustbins etc 6. Polypropylene(PP) Polypropylene is closely connected with polyethylene with respect to raw materials, manufacturing technique as well as properties. The raw materials, i. e. propylene and ethylene, are both contained in a large amount in the decomposing gas of petroleum. Above all, polypropylene and polyethylene are manufactured with the same industrial method, namely, through polymerization with catalyzer under low pressure. Polypropylene is an equilibrious polymer, with regular molecular structure and orderly arrangement, and which is provided with high crystallinity and superior heat resistance and intensity. Its relative density is 0.90-0.92 and thus is the lightest plastic. It can burn like polyethylene after being ignited, with rather stinky smoke, which can be differentiated from polyethylene. The softening point of polypropylene, far higher than polyethylene of high density, can reach 170C. It is of sound transparency and high tensile resistance and surface hardness Polypropylene is of low impact resistance under low temperature Foodstuff containers made of such substance can crack easily if falling off during their being taken in or out of the refrigerator. moreover, it cannot resist against ultraviolet radiation Polypropylene can be used to make shells of electric appliances, water buckets, foodstuff containers, pipes and tubes, filter cloth, fishnet and ropes etc 7. Flurocarbon Resins Flurocarbon resin is a kind of engineering plastic with excellent performance. Its chemical sistance and electric insulation is the best among plastics and its property will not change whether under high temperature or low temperature. The price, however, is a bit too high Flurocarbon resin contains various types of polymers, though in industry only four types are available: quadri-fluorinated-resin, tri-fluorinated-resin, polyvinylidene fluoride and FEP resin. It is basically made through the polymerization of dichlorodifluoro-methane monomer. The advantage of Flurocarbon resin over other plastics is that it is against erosion from chemicals and is sound in such electric properties as heat resistance and high frequency resistance. Quadri-fluorinated-resin, tri-fluorinated-resin and polyvinylidene fluoride are stable respectively ithin the range of-200℃-250℃,-200℃~250℃and-60℃-150℃. Since it does not absorb moisture. the substance can serve as the ideal electric insulation or anti-erosion material. It can be improved in performance and can be miniaturized respect to the field of wireless communication equipment such as electric instruments, radars, televisions as well as microwave relay devices etc. Polyvinylidene fluoride can fight against ultraviolet radiation and its performance remains unchanged all the year round. Endowed with such attributes, it can be applied in building material 8. Polyamide Resins(Nylon, PA)
polyethylene; the smaller the index is, the larger the molecular weight and the higher the mechanical strength, although the fluidity is lower. The low heat resistance and the inactive chemical property of polyethylene result in bad printing and bonding. The substance can be used to manufacture all kinds of bottles, fishnet, ropes, cables, telephone wire stringing, chopping boards as well as dustbins etc. 6. Polypropylene (PP) Polypropylene is closely connected with polyethylene with respect to raw materials, manufacturing technique as well as properties. The raw materials, i.e. propylene and ethylene, are both contained in a large amount in the decomposing gas of petroleum. Above all, polypropylene and polyethylene are manufactured with the same industrial method, namely, through polymerization with catalyzer under low pressure. Polypropylene is an equilibrious polymer, with regular molecular structure and orderly arrangement, and which is provided with high crystallinity and superior heat resistance and intensity. Its relative density is 0.90~0.92 and thus is the lightest plastic. It can burn like polyethylene after being ignited, with rather stinky smoke, which can be differentiated from polyethylene. The softening point of polypropylene, far higher than polyethylene of high density, can reach 170 . It ℃ is of sound transparency and high tensile resistance and surface hardness. Polypropylene is of low impact resistance under low temperature. Foodstuff containers made of such substance can crack easily if falling off during their being taken in or out of the refrigerator. Moreover, it cannot resist against ultraviolet radiation. Polypropylene can be used to make shells of electric appliances, water buckets, foodstuff containers, pipes and tubes, filter cloth, fishnet and ropes etc. 7. Flurocarbon Resins Flurocarbon resin is a kind of engineering plastic with excellent performance. Its chemical resistance and electric insulation is the best among plastics and its property will not change whether under high temperature or low temperature. The price, however, is a bit too high. Flurocarbon resin contains various types of polymers, though in industry only four types are available: quadri-fluorinated-resin, tri-fluorinated-resin, polyvinylidene fluoride and FEP resin. It is basically made through the polymerization of dichlorodifluoro-methane monomer. The advantage of Flurocarbon resin over other plastics is that it is against erosion from chemicals and is sound in such electric properties as heat resistance and high frequency resistance. Quadri-fluorinated-resin, tri-fluorinated-resin and polyvinylidene fluoride are stable respectively within the range of -200℃~250 , ℃ -200℃~250 and ℃ -60℃~150℃. Since it does not absorb moisture, the substance can serve as the ideal electric insulation or anti-erosion material. It can be improved in performance and can be miniaturized with respect to the field of wireless communication equipment such as electric instruments, radars, televisions as well as microwave relay devices etc. Polyvinylidene fluoride can fight against ultraviolet radiation and its performance remains unchanged all the year round. Endowed with such attributes, it can be applied in building materials. 8. Polyamide Resins (Nylon, PA)
Nylons are generally tough and strong and boast high oil resistance and chemical resistance They can be in stable use whether under high temperature or low temperature and hence possess excellent qualification for being used as engineering plastics. The friction coefficient of nylons is small, which indicates that it is high in abrasion resistance. Their friction coefficient against steel is 0. 15, whereas that of polyamide against polyamide is 0. 1. Therefore, nylons or polyamide resins are specially used to manufacture mechanical parts and pulleys such as the small gears, cam and axletrees of recorders, duplicating machines as well as computers. Nylons can absorb moistures easily, whereby their dimension and strength will change with the absorption. Hence, special attention should be paid when it requires high precision and the materials must be fully dried during molding The substance can be used to make such products as gears, connector of electric appliances, lamp shells, engine fan blades, mirrors, crusts, electronic parts, axletrees, computers, TV modules, roller skates soles, ball cases, zippers, fishing threads, brush hair, combs, high pressure tubes and 9. Acetal Resins(POM) POM is a tough and strong material with sound heat resistance and solvent resistance. The property of POM is similar to nylon and PC, which is pretty strong and requires high thermal deformation temperature. In addition, the substance is superior in abrasion resistance and will not easily get deformed even under long-time loading. Moreover, its property hardly changes after repeated bending, and thus it is also called plastic spring. Its low friction coefficient against steel almost equals that of nylon and its dimension change attributed to moisture absorption is also far ower than that of nylon camera parts, internal parts of clocks and watches, zippers as well as computer parts ef os, cams, The substance can be used to make vehicle parts, gears, electronic parts, water ta 10. Polycarbonate Resin(PC) PC is a kind of colorless or primrose material, with high tensile strength, bending intensity, elasticity and impact resistance. These physical properties, almost equal to metallic materials, will not change dramatically with different temperature and the intensity can be retained under 140C Its brittle temperature is as low as-100C-140C and the impact resistance is pretty high mounting to the top among plastics. It can be made into rubber helmets and safety helmets. It is also provided with strong resistance against ultraviolet radiation; a weather resistance test wherein the substance is exposed outdoors for ten years proves that its mechanical property remains tota unchanged. In addition, it is sound in electric property. The chemical resistance is against acid rather than alkali. Only when temperature reaches 220 C-230C will PC begin to be softened and fused. Due to its high viscosity, the substance, during molding and processing, requires high temperature and pressure higher than that of polystyrene or propylene resins PC can be manufactured into safety helmets, various mechanical parts and shells as well as components of electric mechanic appliances which require high electric insulation, intensity, heat resistance, transparency, vibration endurance and stable dimension. 11. Cellulose plastics The cellulose plastic is provided with high transparency and pliability as well as sound
Nylons are generally tough and strong and boast high oil resistance and chemical resistance. They can be in stable use whether under high temperature or low temperature and hence possess excellent qualification for being used as engineering plastics. The friction coefficient of nylons is small, which indicates that it is high in abrasion resistance. Their friction coefficient against steel is 0.15, whereas that of polyamide against polyamide is 0.1. Therefore, nylons or polyamide resins are specially used to manufacture mechanical parts and pulleys such as the small gears, cam and axletrees of recorders, duplicating machines as well as computers. Nylons can absorb moistures easily, whereby their dimension and strength will change with the absorption. Hence, special attention should be paid when it requires high precision and the materials must be fully dried during molding. The substance can be used to make such products as gears, connector of electric appliances, lamp shells, engine fan blades, mirrors, crusts, electronic parts, axletrees, computers, TV modules, roller skates soles, ball cases, zippers, fishing threads, brush hair, combs, high pressure tubes and gunstock etc. 9. Acetal Resins (POM) POM is a tough and strong material with sound heat resistance and solvent resistance. The property of POM is similar to nylon and PC, which is pretty strong and requires high thermal deformation temperature. In addition, the substance is superior in abrasion resistance and will not easily get deformed even under long-time loading. Moreover, its property hardly changes after repeated bending, and thus it is also called plastic spring. Its low friction coefficient against steel almost equals that of nylon and its dimension change attributed to moisture absorption is also far lower than that of nylon. The substance can be used to make vehicle parts, gears, electronic parts, water taps, cams, camera parts, internal parts of clocks and watches, zippers as well as computer parts etc. 10. Polycarbonate Resin (PC) PC is a kind of colorless or primrose material, with high tensile strength, bending intensity, elasticity and impact resistance. These physical properties, almost equal to metallic materials, will not change dramatically with different temperature and the intensity can be retained under 140 . ℃ Its brittle temperature is as low as -100℃~140℃ and the impact resistance is pretty high, amounting to the top among plastics. It can be made into rubber helmets and safety helmets. It is also provided with strong resistance against ultraviolet radiation; a weather resistance test wherein the substance is exposed outdoors for ten years proves that its mechanical property remains totally unchanged. In addition, it is sound in electric property. The chemical resistance is against acid rather than alkali. Only when temperature reaches 220℃~230℃ will PC begin to be softened and fused. Due to its high viscosity, the substance, during molding and processing, requires high temperature and pressure higher than that of polystyrene or propylene resins. PC can be manufactured into safety helmets, various mechanical parts and shells as well as components of electric mechanic appliances which require high electric insulation, intensity, heat resistance, transparency, vibration endurance and stable dimension. 11. Cellulose Plastics The cellulose plastic is provided with high transparency and pliability as well as sound