Preparation, Cross-Linking and Characterization of Novel Benzocyclobutene-Siloxane Polymers with Polysiloxane Mainchain and Silylbenzocyclobutene Pendant Groups

A series of BCB-siloxane polymers with benzocyclobutene (BCB) pendant groups and polysiloxane mainchain was prepared by the hydrosilylation reaction between 4-(1,1-di-methyl-1-vinyl) silylbenzocyclobutene (4-DMVSBCB) and poly (methylhydrosiloxane) (PHMS) employing Pt/C as catalyst. Upon heating the BCB-siloxane polymers, the cross-linking occurred via ring-opening of benzocyclobutene as evidenced by on-line FT-IR, 1H NMR and 13C NMR. TGA examination indicates that the thermal stability was enhanced with increasing the incorporation ratio of BCB. Most importantly, the initial decomposition temperature of crosslinked BCB-siloxane resins is as high as 429 oC, showing a superior thermal resistance over most other BCB resins.