Cyclic oligomers obtained by polymerization of 2,2-dimethyltrimethylene carbonate in the presence of ϵ-caprolactam

Expected and unexpected reactions in ring-opening (co)polymerization

“…Reaction of the chain ends results in a homologous series of cyclic oligomers 47 containing one EClam unit and x DTC units. [29] When Bu 2 Mg and Al(OR) 3 are used as initiators, the resulting active PDTC* does not interact with Clam in solution at r. t. However, when a mixture of active PDTC* is heated with e-caprolactam and N-acyl-e-caprolactam to 125 8C an amorphous copolymer is obtained with a T g of -10 8C. According to NMR analysis this copolymer is strictly alternating, i. e. an alternating poly(ester-urethane) is obtained.…”