Cellulose acetate, a thermoplastic, was developed about the same time as the urea-based resins. Similar in structure to cellulose nitrate, it was found to be safer to process and use. Cellulose acetate was introduced as a molding compound in 1927.
The period 1930-1940 saw the initial commercial development of today’s major thermoplastics: polyvinyl chloride, low density polyethylene, polystyrene, and polymethyl methacrylate. The advent of World War II in 1939 brought plastics into great demand, largely as substitutes for materials in short supply, such as natural rubber. In the United States, the crash program leading to large-scale production of synthetic rubbers resulted in extensive research into the chemistry of polymer formation and, eventually, to the development of more plastic materials.
The first decade after World War II saw the development of polypropylene and high density polyethylene and the growth of the new plastics in many applications. Linear low density polyethylene was introduced in 1978 and made it possible to produce polyethylenes with densities ranging from 0.90 to 0.96. Large-scale production of these materials reduced their cost dramatically. The new materials began to compete with the older plastics and even with the more traditional materials such as wood, paper, metal, glass, and leather. The introduction of alloys and blends of various polymers made it possible to tailor properties to fit certain performance requirements that a single resin could not provide. The demand for plastics has increased steadily; plastics are now accepted by designers and engineers as basic materials along with the more traditional materials. The automotive industry, for instance, relies on plastics to reduce weight and thus increase energy efficiency.
Source : www.plasticsindustry.org/AboutPlastics/content.cfm?ItemNumber=670
The period 1930-1940 saw the initial commercial development of today’s major thermoplastics: polyvinyl chloride, low density polyethylene, polystyrene, and polymethyl methacrylate. The advent of World War II in 1939 brought plastics into great demand, largely as substitutes for materials in short supply, such as natural rubber. In the United States, the crash program leading to large-scale production of synthetic rubbers resulted in extensive research into the chemistry of polymer formation and, eventually, to the development of more plastic materials.
The first decade after World War II saw the development of polypropylene and high density polyethylene and the growth of the new plastics in many applications. Linear low density polyethylene was introduced in 1978 and made it possible to produce polyethylenes with densities ranging from 0.90 to 0.96. Large-scale production of these materials reduced their cost dramatically. The new materials began to compete with the older plastics and even with the more traditional materials such as wood, paper, metal, glass, and leather. The introduction of alloys and blends of various polymers made it possible to tailor properties to fit certain performance requirements that a single resin could not provide. The demand for plastics has increased steadily; plastics are now accepted by designers and engineers as basic materials along with the more traditional materials. The automotive industry, for instance, relies on plastics to reduce weight and thus increase energy efficiency.
Source : www.plasticsindustry.org/AboutPlastics/content.cfm?ItemNumber=670
No comments:
Post a Comment