Search results
Results from the WOW.Com Content Network
The plastic kits and covers are mostly made of synthetic polymers like polythene, and tires are manufactured from polybutadienes. [1] However, due to the environmental issues created by these synthetic polymers which are mostly non-biodegradable and often synthesized from petroleum, alternatives like bioplastics are also being considered.
By 1930, General Motors and Du Pont formed the Kinetic Chemical Company to produce Freon, and by 1935, over 8 million refrigerators utilizing R-12 were sold by Frigidaire and its competitors. In 1932, Carrier began using R-11 in the worlds first self-contained home air conditioning unit known as the "atmospheric cabinet".
One important classification of plastics is the degree to which the chemical processes used to make them are reversible or not. Thermoplastics do not undergo chemical change in their composition when heated and thus can be molded repeatedly. Examples include polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). [13]
The remaining 5% of BPA is used in a wide range of applications, many of which involve plastic. [49] BPA is a main component of several high-performance plastics , the production of these is low compared to other plastics but still equals several thousand tons a year.
Polyethylene was first synthesized by the German chemist Hans von Pechmann, who prepared it by accident in 1898 while investigating diazomethane. [12] [a] [13] [b] When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the white, waxy substance that he had created, they recognized that it contained long −CH 2 − chains and termed it polymethylene.
Kinetic Chemicals patented the new fluorinated plastic (analogous to the already known polyethylene) in 1941, [12] and registered the Teflon trademark in 1945. [ 13 ] [ 14 ] By 1948, DuPont, which founded Kinetic Chemicals in partnership with General Motors , was producing over 910,000 kilograms (2,000,000 lb) of Teflon-brand ...
Polypropylene is commonly used in car bumpers, interior trims, and other components [19] where TiO₂ is added to improve the UV stability of the plastic, ensuring that parts do not degrade or lose color when exposed to sunlight over time. [20] Polyethylene films are widely used in agriculture for greenhouses, mulching, and silage wraps. [21]
MDI finds considerable use in PU foam production. [43] Polyurethanes are used to make flexible foam for mattresses and seating, rigid foam insulation for refrigerators and freezers, elastomeric shoe soles, fibers (e.g. Spandex), coatings, sealants and adhesives. [44] The term polyol is also attributed to other molecules containing hydroxyl groups.