Synthesis of alpha,omega-hydroxyalkyl telechelic polydimethylsiloxane soft segments and preparation of waterborne polyurethane-polydimethylsiloxane block copolymers

摘要

In this paper, by optimizing synthesis process of alpha,omega-hydroxyalkyl telechelic polydimethylsiloxane, alpha,omega-bis(3-(1-methoxy-2-hydroxypropoxy)propyl)polydimethyl siloxane (PMTS), the yield of hydrosilylation product, 1,3-bis(glycidoxypropyl) tetramethyldisiloxane exceed 86.5%. By tracing the change of methanol (gravimetry) and measuring the change of molecular weights of polydimethylsiloxanes at different reaction time (titration), the optimum reaction time of methoxylation reaction and ring-opening polymerization was determined as 8 and 12h. Using alpha,omega-bis(3-(1-methoxy-2-hydroxypropoxy)propyl)polydimethyl siloxane with different molecular weights, waterborne polyurethane-polydimethylsiloxane block copolymer were prepared. The influences of molecular weights and content of alpha,omega-hydroxyalkyl telechelic polydimethylsiloxane on the waterborne polyurethane-polydimethylsiloxane block copolymers were investigated in detail. The addition of alpha,omega-hydroxyalkyl telechelic polydimethylsiloxane could improve the water-resistance property obviously and increase the elongation at break. However, the mechanical property was reduced with increase of content and molecular weight of alpha,omega-hydroxyalkyl telechelic polydimethylsiloxane.