Synthesis and Characterization of Aromatic Polyester and Polysiloxane ContainingBlock Copolymers: Multiphase Transparent Atomic Oxygen Resistant Damping Materials, Liquid Crystal Films, and Toughening Components of Sol/Gel Glasses

摘要

AFOSR sponsored research on multifunctional polymers which has been conducted inour laboratories over the past three years covers three main areas. Each of the three areas is summarized below and described more completely in some depth in the three sections of this report. The first area includes the synthesis of siloxane modified silicate ceramics produced by sol-gel chemistry followed by ultrastructure processing. Using techniques such as acid free hydrolysis condensation reaction systems, it has been possible to incorporate at least 30% of siloxane oligomers via cohydrolysis of suitably terminated materials in the presence of TMOS. In different but somewhat related work based upon polyimides, extensive studies have been conducted with linear thermoplastic polyimide siloxane copolymers. The polyimide siloxane copolymers prepared to date have been based largely upon aliphatic terminated polydimethyl-siloxanes which have adequate thermal stability for most purposes. The third area of investigation on multifunctional polymers was the synthesis and characterization of isotropic polyarylene sulfone, anisotropic aromatic polyester liquid crystal copolymers. We have demonstrated that with as little as 10 or 15 weight % of the liquid crystal segment, organic solvents which would easily dissolve or stress crack the amorphous engineering homopolymers like polysulfones, are no longer able to do so. Multifunctional polymers; Sol-gel; Polysiloxane modified silicates; Polyimide-siloxane copolymers; Isotropic-anisotropic copolymers; Electronic materials; Ceramic materials. (jg)