Plastic

Plastics (plastic substances, plastic) materials obtained on the basis of natural (casein, horn, oil asphalts and others) and mainly synthetic (polyethylene, polystyrene, polyvinyl chloride, and mn. other) macromolecular compounds (polymers). Under heat and pressure well molded plastic, form the web, film, and after cooling, or hardening steadily maintain the shape imparted to them. Products from plastic, with low density, high mechanical strength, excellent thermal and electrical insulation properties, chemical resistance, and others, have received wide application in engineering, life, medicine and pharmacy. Cm. also high-Molecular compounds.

Plastics (plastic masses, plastics) - artificial materials, produced on the basis of synthetic polymers - high-molecular compounds. Plastics may consist entirely of polymers obtained by the polymerization or polycondensation of low-molecular compounds. So, polyvinyl alcohol is the basis for winola; polyamides - of nylon and nylon; polyvinyl chloride - for chlorine; PTFE - polytetrafluoroethylene; polyethylene, polypropylene, polystyrene, poly (methyl methacrylate) and so on for other plastics. Using the method of structural and chemical modification in obtaining of high-molecular compounds (see), produce plastic, resistant against rotting, abrasion etc.,
More numerous P. complex composition, in which, in addition to the polymer, which is binding substances, introduce fillers (increase the mechanical strength, reduce the consumption of polymers and cost-cutting P.), plasticizers (which increases flexibility, elasticity and frost resistance, etc), stabilizer (increasing resistance to external influences), antiseptics, dyes, porophores, lubricants and other Fillers are powdered (wood and quartz powder, asbestos powder, talc, graphite and other), fiber (asbestos and glass fiber, cotton Linter and other), leaf (paper, cardboard, cotton, glass or asmodai). High-strength plastic, used in machine building and instrument making, get a soaking fabrics phenol-formaldehyde resins (see synthetic Resins). Changing the composition of Petrograd, it is possible to obtain materials with predetermined properties, for example with low specific weight, high strength, elasticity, transparency, thermal and chemical-resistant, able to stretch out in the threads, be molded and so on
Using plastic to replace expensive metals in construction - as finishing materials, and porous and cellular (foams) - as sound and heat insulators. Chemically resistant P. - Teflon, etc. is used in chemical appliances ... and instrument engineering, pharmacy and medicine (surgery). However, chemical resistance does not mean inaction or harmlessness P. for implanting them in a living organism. Here can't Express themselves chemical, physical and physicochemical properties of P. Thus, implantation P. may lead to the formation of tumors. When using plastics in construction as finishing materials necessary to consider the possibility of releasing hazardous to the health of monomers and dimers in the air, electrical insulating properties P. floors of P. may occur electrification, to experience the electric discharges dangerous when working with flammable substances. Besides, electrification can disrupt the correct functioning of many devices, etc.