New polymer syntheses, 108 - Controlled degradation and in-situ functionalization of polycarbonates by means of Bu2SnO

It was found that diphenyl carbonate reacts with Bu2SnO above 140 degreesC yielding CO2 and Bu2Sn(OPh)(2). This insertion reaction was also successful ly applied to a polycarbonate prepared from polytetrahydrofuran diol-1000 a nd Bu2SnO containing macrocyclic polyTHF dioxides. Bu2SnO reacted analogous ly with poly(bisphenol A) carbonates yielding tin-containing rapidly crysta llizing cyclic oligocarbonates. Their treatment with 1,2-ethanedithiol gave linear oligocarbonates having two 1,2-ethanedithiol gave linear oligocarbo nates having two OH end groups. Bu2Sn-containing macrocyclic oligocarbonate s reacted in-situ with several carboxylic acid chlorides, forming telecheli c oligocarbonates with functional ester end groups. Bu2Sn-containing macro- cycles also reacted in-situ with terephthaloyl chlorides yielding a poly(es ter carbonate).