Reduction of the shrinkage of thermosets by the cationic curing of mixtures of diglycidyl ether of bisphenol A and 6,6‐dimethyl‐(4,8‐dioxaspiro[2.5]octane‐5,7‐dione)

Ytterbium and lanthanum triflates were used as initiators to cure mixtures of diglycidyl ether of bisphenol A and 6,6-dimethyl-(4,8-dioxaspiro(2.5)oc- tane-5,7-dione) in several proportions. The evolution of the epoxy and 6,6-dimethyl- (4,8-dioxaspiro(2.5)octane-5,7-dione) bands during curing and the linear ester groups in the final materials were evaluated with Fourier transform infrared in the attenu- ated-total-reflection mode. The use of a conventional cationic initiator, boron trifluor- ide monoethylamine, was also studied to test the advantages of lanthanide triflates. The shrinkage after curing and the thermal degradability of the materials with varia- tions in the comonomer ratio and the initiator were evaluated and related to the chemical structure of the final network. V C 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6869-6879, 2006

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