Bisphenol-A polycarbonate/polydimethylsiloxane multiblock copolymers .1. Synthesis and characterization

Aminopropyl-terminated polydimethylsiloxane (PDMS)-bisphenol-A polycarbonate block copolymers were synthesized by interfacial phosgenation reaction of 2,2-bis (4-hydroxyphenyl) propane (BPA) and aminopropyl-terminated PDMS. A new synthetic procedure shows better conversion yield of PDMS oligomer. IR, H-1, C-13, and Si-29 nuclear magnetic resonance spectra were used to identify the exact chemical structures of the PDMS-PC block copolymers. The conversions of PDMS of these copolymers were similar to 90% and independent of the PDMS content. The intrinsic viscosities, TV, [eta] studied were in the range between 0.23 and 2.25 dL/g in dichloromethane at 25 degrees C with different reaction conditions. The intrinsic viscosity and the glass transition temperature decreased with increasing PDMS content at the same reaction temperature, while the melting flow indices increase with increasing PDMS content. Transparent and colorless films, which showed good oxygen-to-nitrogen permselectivity, could be cast from dichloromethane. (C) 1997 John Wiley & Sons, Inc.