Polyphenylene oxide filler

Between 250 and 450°F (121 and 232°C), plastics used include glass or mineral-filled phenolics, melamines, alkyds, silicones, nylons, polyphenylene oxides, polysulfones, polycarbonates, methylpentenes, fluorocarbons, polypropylenes, and diallyl phthalates. The addition of glass fillers to the thermoplastics can raise the useful temperature range as much as 100°F and at the same time shortens the molding cycle. 

Dimensional stability There is plastics with very good dimensional stability, and they are suitable where some age and environmental dimensional changes are permissible. These materials include polyphenylene oxide, polysulfone, phenoxy, mineral-filled phenolic, diallyl phthalate, epoxy, rigid vinyl, styrene, and various RPs. Such products will gain from an after-bake for dimensional stabilization. Glass fillers will improve the dimensional stability of all plastics. 

Phenolic glass and a diallyl phthalate glass material are available with very low shrinkage. Glass and other mineral fillers minimize the thermal expansion differential problem. Phenoxy and polyphenylene oxides are examples of being low in shrinkage and thermal expansion. 

Many other reports have demonstrated the smoke suppressing tendencies of hydrated fillers in various polymers including ethylene-propylene-diene elastomers,43 PP,38 polystyrene,49 modified polyphenylene oxide, polybutylene terephthalate, and ABS.37 In addition to suppressing smoke generation, a delay in the onset of smoke evolution is also achievable.25 Figure 7.5 illustrates smoke reductions obtained in PP. 

Plastics that are readily bonded with induction methods include all grades of acrylonitrile butadiene styrene (ABS), nylon, polyester, polyethylene, polypropylene, and polystyrene, as well as those materials often considered more difficult to bond such as acetals, modified polyphenylene oxide, and polycarbonate. Reinforced thermoplastics with filler levels up to 65 pCTcent have been joined successfully. Many combinations of dissimilar materials can be bonded with induction welding processes. 

Nelson [136] has reported studies of zinc, zinc oxide, and zinc borate in coatings on or as a filler in modified polyphenylene oxide (m-PPO). Zinc arc spray, or zinc, zinc borate, and zinc/zinc borate in epoxy coatings showed a substantial reduction of flame spread index (ASTM E-162) (I,) for m-PPO. Zinc oxide in epoxy, however, showed a dramatic increase in I, on m-PPO. Zinc arc spray on m-PPO led to enhanced stability in the 500-600°C range in both isothermal and GC/MS experiments. It was speculated that since zinc melts at 420OC, just at the early stage of decomposition of m-PPO, this could allow intimate contact with the charring substrate. As in pure polystyrene, char formation is enhanced in air in m-PPO, and this was thought to be enhanced further by the presence of zinc. Indeed it was observed that volatilization of small molecules is reduced for m-PPO with zinc present at temperatures under 700°C, with preference for volatilization of the triaryl phosphate flame retardant, styrene trimer, and PPO dimers. 

Polyphenylene oxides (modified) (20-30 percent glass filler) 1.22... 

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