Synthetic Resins and Plastics
- PDF / 8,817,514 Bytes
- 64 Pages / 504.6 x 720 pts Page_size
- 93 Downloads / 211 Views
INTRODUCTION
*Professor, Plastics Engineering Department. University of Massachusetts at Lowell. (Sections on Commercial Plastic Materials; Plastics Processing.) **Associate Professor, Plastics Engineering Department, University of Massachusetts at Lowell. (Section on Polymer Chemistry.)
nitrate and molded it into billiard balls, and later into combs, brushes, and other useful articles. Commercial synthetic plastics began in 1908 when Leo Baekeland reacted phenol, formaldehyde, and wood flour and molded them into electrical insulators and a growing variety of other product specialties. During the next 30 years, a variety of plastics appeared as interesting specialties. During World War II the U.S. and German governments met the severe demands of advanced military technology by supporting vast research, development, plant construction, and manufacturing of a number of major polymers for plastics and rubber applications. With the end of the war in 1945, all of this technology and production capacity converted to civilian products, and commodity plastics began their tremendous growth, first polyvinyl chloride and polystyrene, then polyethylenes, polypropylene, polyesters, and polyurethanes, along with a constantly expanding range of more specialized polymers for more demanding applications.
662
Riegel s Handbook of Industrial Chemistry, I Oth Edition Edited by Kent. Kluwer Academic/Plenum Publishers, New York 2003
Definition
Plastic (adj.) is defined by Webster as "capable of being molded or modeled (e.g., clay) ... capable of being deformed continuously and permanently in any direction without rupture." Plastic (n.) in modem industry covers high-molecular-weight organic compounds which can be formed into any desired shape and then solidified into a useful product which can withstand the mechanical stresses normally applied to it. History
Commercial plastics began in 1868 when John and Isaiah Hyatt plasticized cellulose
SYNTHETIC RESINS AND PLASTICS
Advantages of Plastics over Conventional Materials
We have had conventional structural materials-metals, ceramics, glass, wood, leather, textiles, paper-for thousands of years, during which time we have been able to explore and exploit them thoroughly to full maturity. By comparison, plastics are so new that we are still learning to develop and use them. Their exponential growth is due to the fact that they offer many advantages over conventional materials. Processability and Product Design. It is much easier to convert plastic materials into an almost unlimited range of products. Modulus. Plastics cover an extremely broad range from extremely rigid to stiffly flexible to extremely soft and rubbery, sometimes even within a single chemical family. Elasticity. Their recovery from deformation is superior to almost all conventional materials. Impact Strength. Plastics are much less brittle than ceramics, glass, and paper, and some families can be made almost unbreakable. Lubricity and Abrasion Resistance. Specific plastic materials offer outstanding selflubricating
Data Loading...
