Polymers of Carbonic Acid. 20. High Molecular Weight Poly(Decamethylene Carbonate) by Ring-Opening Polymerization Initiated with BuSnCl₃ or SnOct₂

Abstract

Cyclobis(decamethylene carbonate), (DMC)₂, was prepared by polycondensation of 1,10-decane diol and diethylcarbonate followed by thermal depolymerization in vacuo. Two series of polymerizations were conducted in bulk at 120°C with BuSnCl₃ as initiator. Either the reaction time was varied at a constant monomer/initiator (M/I) ratio or the M/I ratio was varied at constant reaction time. Two analogous seires of polymerizations were conducted with Sn(II)-2-ethylhexanoate, SnOct₂. Both initiators showed almost equal reactivities, but the highest yields (up to 98%) and the highest molecular weights (M _w up to 88,000) were obtained with BuSnCl₃. Both initiators yielded polyDMC free of ether groups. DSC measurements revealed that polyDMC is a rapidly crystallizing material with a melting temperature (T _m) of 67 ± 1°C. A comparison with poly(alkylene carbonate)s having fewer CH₂ groups demonstrated that the rate of crystallization increases with an increasing number of CH₂ groups.