New High Performance Windshield/Canopy Materials,
ALLIED CHEMICAL CORP MORRISTOWN NJ
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This paper covers a three year program to develop new, thermally stable, transparent plastics for use high performance aircraft windshields andor canopies. Forty-seven new materials were prepared during this period, each with a glass transition temperature exceeding those of currently used acrylic and polycarbonate plastics, and possessing varying degrees of transparency, color and impact strength. Substitution of thermally stable, aromatic diols and diacids by appropriate techniques for bisphenol-A in modified preparatory procedures for polycarbonates and bisphenol-A in modified preparatory procedures for polycarbonates and polyesters has resulted in more thermally stable materials. Depending upon the reactants involved, new polyesters, polycarbonates, polyester-carbonates, copolyesters and copolyester-carbonates were prepared. Concepts governing the choice of monomers and their effects on final polymer properties is presented along with a brief discussion on the importance of molecular chain entanglement in the glassy state.