A novel family of silicone prepolymers

α

ω bis( γ aminopropyl dimethyl ) poly tetramethyl p silphenylene siloxane was synthesized by ring opening copolymerization of octamethylcyclotetrasiloxane (D Me 4)

dodecamethyl cyclotri p silphenylenesiloxane (D Phenylene 3)

and 1

3 bis( γ aminopropyl) tetramethyldisiloxane (M-NH-22) at temperature 160℃ with 95% yield.The prepolymers were characterized by gel permeation chromatography (GPC)

vapor phase osmometer (VPO)

infrared spectroscopy (IR)

nuclear magnetic resonance (NMR)

and thermogravimetric analyses(TGA).The results indicate that the prepolymer has the structure designed.When P-silphenylene siloxane unit contents are over 20%

the temperatures for 20% weight loss in TGA curves are over 540℃

obout 70℃ higher than that of the dimethtl moiety.