PLASTIC MATERIALS USED AND PROPERTIES Plastic materials are used in various application areas for different purposes. Polyethylene (PE): It is the most used and cheapest plastic type. It has high resistance to impact at normal and low temperatures. They are not affected by acids, alkalis and organic solvents. It is transparent and lighter than water. It is generally used in thin film packaging, packaging and covering works, irrigation and sprinkler pipes and in the production of various cheap kitchenware. It catches fire easily, it continues to burn spontaneously outside of the flame. It has good electrical insulation. It can be used underground as it is not affected by salt and bacteria. It has high electrical resistance. Therefore, it is an important insulation material. Since its thermal expansion coefficient is high (160 * 10-6), it is affected by sunlight. Polyvinylchloride (PVC): It is the most used plastic type after polyethylene and it is very cheap. It is resistant to high chemical effects and abrasion. There are two types, hard and soft. Pressurized water pipes, sewage pipes, roof rain gutters and downpipes, irrigation and sprinkler pipes, plastic joinery roofing sheets are produced from the hard ones. Soft ones are used as floor tiles in buildings. They are resistant to burning with flame and emit toxic gas with it. It has also been used frequently in door and window construction in recent years. PVC pipes are not used in hot water installations as they soften at 80ºC. Polypropylene (PP): Its strength and softening temperature is quite high and it is lighter than water. Like polyethylene, its smell is sharper and more caustic. It has properties similar to PE. Gas is used in the air filters of vehicles, reinforced with asbestos fibers, and is also used in packaging and sack works. ABS (acronitrile-butadiene-styrene): It is a triple copolymer and has high strength and toughness. It is resistant to external and chemical effects. Tensile strength is 42-50Mpa, specific gravity is 1.05-1.07 Mg / m3, they have no elasticity module and they can withstand temperatures up to 75? C. They are used in the production of pipes, auto parts, electronic device cabinets and refrigerator parts. Polystyrene (PS): Glass clear, easy to color, bright hard surface, solid and crisp, tasteless and odorless, very good electrical properties, weldable, brittle, easy to process and cheap. It is easily flammable and continues to burn brightly outside of the flame. It has a sweet scent that does the job strongly. It is a good insulating foil for building elements used in electronics. Foamed (styropor) is used in heat and sound insulation, shaped foamed PS is used in packaging, mold model casting and steel concrete structures, toys, kitchenware. Nylon: Nylon, which is included in the polyamides group, has high strength, rigidity and toughness and is resistant to abrasion. As the crystallization rate increases, its mechanical properties and softening temperature increase. Nylon is copolymer and classified according to the number of C atoms in different types of mers. They can catch fire and continue to burn spontaneously outside of the flame. Although nylon is easy to manufacture, it is a bit expensive. They are used in processes such as gears, bearings and similar machine parts, sliding elements, pulleys, connections. Polycarbonate (PC): It is hardly flammable, goes out when pulled from the flame and has an exiting flame. It is glass clear, easy to color, resistant to climate change, can be used at temperatures up to 120? C, does not take water, therefore conducts electricity well, has a very high strength and toughness, and its dimensions are stable. They are also affected by strong acids and bases, and there is a risk of stress rupture and pain. They are used in fine work and electronic building elements, insulation screws, lighting devices, car taillights that are affected by heat, and tableware. Polytetrafluoro ethylene (Teflon): Teflon with a symmetrical and homogeneous molecular structure is largely crystallized. For this reason, it is considered to be the polymer with the highest specific gravity (2,3gr / cm3), its resistance to abrasion is high, its friction coefficient is very low. It is suitable to be used between 200? C and 260? C. It is very resistant to chemical effects. It is resistant to high temperatures and does not stick, so it is used in kitchen utensils. It is used in bridge supports and in coating the inner parts of pipes carrying solid materials. Polymethyl Methacrylate (PMMA): It belongs to the group of Akriks. It is transparent, hard, rigid and resistant to external influences. It catches fire easily, it continues to burn spontaneously outside of the flame. It is used in all kinds of glass coverings, lampshades, showcase glasses, painting devices, art objects. It is known as Plexiglass in the market. Phenolics: Bakelite, considered one of the most important industrial plastics, is the first synthetic phenolic polymers developed. It is a plastic type with high strength and hardness, resistant to temperature and chemical effects, easy to apply and very cheap. Pine Its strength can be increased by reinforcing the fiber with cotton and wood shavings. It is used in the production, coating and bonding of various parts in the electrical and auto industry.

Epoxies: High strength and hardness, resistant to external chemical effects and stable dimensions. It is used in protective and decorative works. They easily adhere to other materials, so they are widely used. Epoxy resins are used in adhesion works in buildings, to cover cracks, to protect surfaces against external influences. Although it is convenient to be useful in aircraft and spacecraft bodies, sports equipment, it is very expensive.

Polyesters: Although unsaturated covalently bonded polyesters are low viscosity linear polymers, they form cross-linked by processing together with additives and convert it into thermoset plastic. It is well resistant to external influences.

Silicones: Silicones are formed by attaching organic side groups to an inorganic chain consisting of silicon and oxygen. The inorganic component makes silicones resistant to temperature, while the organic component gives them flexibility. Therefore, they have the ability to polymerize. However, it is difficult for Si atoms to form a space network structure among themselves. Chains will be unstable. Instead, they polymerize by easily forming bonds with oxygen atoms. For this reason, they are called Silicon. Depending on the molecular structure and degree of polymerization, they are available as silicone rubber, silicone grease and silicone oil.