SYNTHESIS AND CHARACTERIZATION OF ALPHA,OMEGA-BIS(4-HYDROXYBUTYL) POLYDIMETHYLSILOXANES

alpha,omega-Bis(4-hydroxybutyl) polydimethylsiloxane (molecular weight 1500 to 4500) can be prepared with well-controlled molecular weight t hrough the reaction of 1,3-bis(4-hydroxybutyl)tetramethyl disiloxane a nd dimethoxydimethyl silane or diethoxydimethyl silane in the presence of a stoichiometric amount of water and hydrochloric acid. The molecu lar weight of these hydroxybutyl-terminated polysiloxanes can be deter mined fairly consistently by a titration method. These polysiloxanes a re stable toward cyclization. (C) 1995 John Wiley and Sons, Inc.