LINEAR DIACETYLENE POLYMERS CONTAINING BIS(DIMETHYLSILYL) PHENYL AND OR BIS(TETRAMETHYLDISILOXANE)CARBORANE RESIDUES - THEIR SYNTHESIS, CHARACTERIZATION AND THERMAL AND OXIDATIVE PROPERTIES/

A series of inorganic-organic linear diacetylenic hybrid polymers (5a- e) were prepared by the polycondensation reaction of 1,4-dilithiobutad iyne with 1,4-bis(dimethylchlorosilyl)benzene and/or 1,7-bis(tetrameth ylchlorodisiloxane)-m-carborane. Their structures were characterized u sing FTIR, and C-13 and H-1 NMR spectroscopies, and their thermal and oxidative properties were evaluated by DSC and TGA analyses. The hybri d polymers exhibited solubility in common organic solvents and were vi scous liquids or low melting solids at room temperature. Broad promine nt exotherms, attributed to reaction of the diacetylenic units, were o bserved by DSC in the 306 degrees C to 354 degrees C temperature range . When 5a-e were analyzed by TGA to 1000 degrees C under nitrogen, wei ght retention between 79 and 86% were obtained. Ageing studies, perfor med at elevated temperatures in air on a thermoset and a ceramic obtai ned from polymer 5b, showed this system to have excellent thermal and oxidative stability. (C) 1997 John Wiley & Sons, Inc.