A series of block-copolymers based on aminopropyl-terminatedpolydimethylsiloxane or polyurea modified polysiloxane oligomers

4

4'-methylenediphenylenediisocyanate and 1

4'-Bis (2-hydroxythyl) piperazine was synthesized．Ionization was accomplished by using iodoethane and γ-propane sultone respectively．All of the samples are transparent and exhibit thermoplastic mechanical properties ina wide range of temperature The morphology of these samples was studied in detailby using FT-IR

DSC and DMTA etc．It Was found that the incorporation of polyurea chain into polydimethylsiloxane soft segments increased the phase mixingand resulted in higher Young’S modules

ultimate tensile strength and elongation thanthe polydimethylsiloxane polyurea-urethane system.