Modified polyphenylene oxide thermal

Modified-polyphenylene oxide (or ether) is a blend of high impact polystyrene (PS) and polyphenylene oxide (PPO), plus thermal stabilizers and a triarylphosphate flame retardant. Studies of the mechanism of the flame retardant in modified-polyphenylene oxide have shown some evidence for both solid phase and vapor phase inhibition (4). Indeed, one is always interested to know whether flame retardant action is on the solid or vapor phase. 

An initial experiment involved determination of Arapahoe Smoke Chamber results for samples with and without the zinc coating present. Data are presented in Table II. Depending upon orientation of the sample, an increase in char occurred for some samples with zinc present, while no change in smoke formation was seen. Initial pyrolysis GC/mass spectroscopy results at 90CPC in helium showed no difference in volatiles formed with or without zinc. These results suggested enhanced char formation as the origin of the Radiant Panel results for zinc on modified-polyphenylene oxide (m-PPO). Zinc oxide is a known, effective thermal stabilizer in the alloy. The next work then focused on DSC/TGA studies. 

Polystyrene modified polyphenylene oxide (PPO) or Noryl can be hot plate welded at 260 to 288°C and 20 to 30 s contact time. Unmodified PPO can be welded at hot plate temperatures of 343°C. Excellent spin welded bonds are possible with modified polyphenylene oxide (PPO), because the low thermal conductivity of the resin prevents heat dissipation from the bonding surfaces. Typical spin welding conditions are rotational speed of 40 to 50 ft/min and a pressure of 300 to 400 psi. Spin time should be sufficient to ensure molten surfaces. 

A modified epoxy matrix for Kevlar FRP composites was produced from ep>oxy/polyphenylene oxide (PPO) blends cured with multifunctional cyanate ester resin [94]. The effects of the PPO content on the cme behavior in the cyanate ester-cmed epoxy were investigated with FTIR. The cme reaction in the ep>oxy/PPO blends was faster than that of the neat epoxy system. FTIR analysis revealed that the cyanate fimctional group reactions were accelerated by adding PPO and that several co-reactions had occurred. Thermal mechanical analysis showed that the thermal stability of the epoxy/PPO matrix is improved by adding PPO. In the respective compursites, the ISS values between Kevlar fiber and the epoxy/PPO blends are almost the same as those between Kevlar fiber and neat epoxy. The ILSS in the respective laminates increases with the PPO content, which was attributed to an increase in the composites ductility. 

Property data for GRTP s are presented in two major breakouts. In the first breakout, the basic resins—styrene acrylonitrile (SAN), polycarbonate, polysulfone, polyacetal, polypropylene, polyphenylene oxide (PPG), nylon, modified PPG, and polyvinyl chloride—are treated as the independent variables and the physical, mechanical, electrical, thermal, chemical, and weathering characteristics are treated as the dependent variables. In the second breakout, the functional relationships are reversed, te., the properties are the independent variable and the resins are the dependent variable. ASTM test methods by which the physical values were determined are listed. The. physical data versus resins are presented in both tabular and graphic form. 

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