New polymer syntheses. 105. Syntheses of aliphatic poly(thioester)s by ring-opening polycondensation of 2,2-dibutyl-2-stanna-1,3-dithiolane

2,2-Dibutyl-2-stanna-1,3-dithiolane was reacted with various aliphatic dicarboxylic acid dichlorides. In an exothermic reaction, the corresponding polyesters of 1,2-dimercapto ethane were obtained in high yields. These polythioesters were found to be rapidly crystallizing materials with melting temperatures in the range of 125-195 degreesC. The DSC measurements of the polythioester derived from suberic acid suggest that this polymer undergoes a reversible first order transition resulting from a change of the crystal modification. The MALDI-TOF mass spectra indicated the formation of large amounts of cyclic oligo- and polyesters in all cases. The polythioesters proved to be useful reagents for the exchange of Bu2Sn groups in cyclic tin-containing alkylene bisoxides, so that tin- and sulfur-free oligo or polyesters were obtained.