Functionalized Poly (tetramethyl-1,4-silphenylenesiloxane) with Pendant Hydroxyl Groups

Novel functionalized poly(tetramethyl-1,4-silphenylenesiloxane) with pendant hydroxyl groups, i.e., poly[2,5-bis(2-hydroxyethoxy)-tetramethyl-1,4-silphenylenesiloxane] (P1), was synthesized and characterized by differential scanning calorimetry (DSC) thermogravimetry (TG), and X-ray diffraction analysis. P1 was obtained via catalytic deprotective- hydrogenation of poly [2,5-bis(2-benzyloxyethoxy)-tetramethyl-1,4-silphenylenesiloxane] (PreP1), which had been obtained by catalytic polycondensation of 2,5-bis(2-benzyloxyethoxy)-1,4-bis(dimethylhydroxysilyl)benzene (M1) in benzene. PI was revealed to be an amorphous polymer as deduced from DSC as well as X-ray diffraction measurement. and soluble in highly polar solvents as ethanol and methanol in which poly(tetramethyl-1,4-silphenylenesiloxane) (1,4-PTMPS) is insoluble. The glass transition temperature (T(g)) of PI was determined to be 73 degrees C from DSC, which was much higher than that of 1,4-PTMPS (-20 degrees C), indicating that the intermolecular and/or intramolecular hydrogen bondings based on hydroxyl groups restricted the mobility of the main chain. The temperature at 5% weight loss (T(d5)) of P1 (290 degrees C) determined by TG was lower than that of 1,4-PTMPS, indicating that the oxyethylene and/or alcoholic-hydroxyl moieties decline the thermostability; however, the obtained PI would promise to be a new reactive-polymer with hydroxyl moieties to develop new functional materials.