Modified polyphenylene oxide general

The above materials are crystalline polymers, and such materials have generally superior frictional, wear and fatigue properties, compared with amorphous polymers. However, amorphous polymers show lower mould shrinkage and where dimensional accuracy is paramount they may be preferred. Suitable engineering types are polycarbonate (PC) and noryl (styrene modified polyphenylene oxide). 

Within 10 years — from 1959 to 1969 — five new generics were introduced. In 1959, Du Pont introduced polyacetal, and Bayer and General Electric commercialized polycarbonate. Polyphenylene oxide was introduced by General Electric in 1962 and one of the first blends — modified polyphenylene oxide — debuted in 1965. Celanese commercialized polybutylene terephthalate (PBT) in 1968. 

During that year ULTEM polyetherimides were added to General Electric Plastics family of polymers which, at the time, included polycarbonates, modified polyphenylene oxides and polybutylene terephthalate. This addition was noteworthy because it occurred at a time when bringing totally new polymers from the research laboratory to the marketplace had become a rare event. 

Because of the Kmitation of temperature resistance, the use of plastic components in ovens has been mostly limited to exterior trim. Plastics however are gradually being used for semi-structural components. Endcaps with a metallic finish are a typical example. General Electric have used a sputter-coated modified Noryl polyphenylene oxide for a shiny metallic appearance for the Tappan oven. The material provides flame resistance, electrical insulation, and resistance to heat, grease, and abrasion. 

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