New thermosets obtained by the cationic copolymerization of diglycidyl ether of bisphenol A with γ‐caprolactone with an improvement in the shrinkage. I. Study of the chemical processes and physical characteristics

摘要: Diglycidyl ether of bisphenol A was cured with different proportions γ-caprolactone ytterbium triflate as an initiator. The curing studied by means differential scanning calorimetry and Fourier transform infrared in the attenuated total reflection mode. latter used to monitor competitive reactive processes quantify conversions epoxide, lactone, intermediate spiroorthoester groups. partial depolymerization process from material free also identified. formation a stable carbocation coordinative capability were reasons for this unexpected process. thermal dynamic mechanical properties materials determined calorimetry, thermogravimetric analysis, analysis. An increase proportion resulted increased rate, decrease shrinkage after gelation, significant glass transition temperature. introduction ester linkages into three-dimensional structure led more thermally degradable thermosets. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Chem 45: 1968–1979, 2007