THERMOSETTING MECHANISM OF POLY[(PHENYLSI LYLENE)ETHYNYLENE-1,3-PHENYLENEETHYNYLENE]

phenylsilylene)ethynylene-1,3-phenyleneethynylene] (MSP) which contain s Si-H and C=C bonds gives a very highly thermally stable polymer by c uration above 150 degrees C. In this study, we determined thermosettin g mechanism of MSP from the C-13 and Si-29 solid-state NMR methods and chemical calculations. From these results, we concluded that the inte rmolecular cross-linking reactions owing to 1) the Diels-Alder reactio n between Ph-C=C and C=C and 2) the hydrosilylation reaction between S i-H and C=C proceeded at 150 similar to 200 degrees C. A very highly t hermally stable structure is formed. Only the hydrosilylation reaction occurs above 300 degrees C.