The influence of elementary reactions (linear polymerization and crosslinking) on the development of the glass transition temperature (T~) of diglycidyl ether of bisphenol A/diaminodiphenylsulfone (DGEBA/DDS) epoxy resin system has been analysed quantitatively according to a proposed model. The model was derived on the basis of the reaction mechanisms observed in the curing system and the assumption that the Tg has individual linear relationships with the degree of conversion of the two reactions. The conversions of elementary reactions during the cure were obtained experimentally by measuring the changes in the concentrations of epoxy, primary and secondary amine groups with time by near-infra-red spectroscopy. The Tg values were measured by differential scanning calorimetry (d.s.c.). In addition, and for the purpose of comparison, the overall conversion of the system was also obtained from d.s.c, in a dynamic scanning mode. The conversion-time data from the two different techniques were consistent. The proposed model successfully predicted the separate increases in T s due to the linear polymerization and due to the crosslinking reactions. The Di Benedetto equation and the viscoelastic model of Gan et al. are also discussed
Посилання на статтю:
Cure kinetics of elementary reactions of a DGEBA/DDS epoxy resin: 1. Glass transition temperature versus conversion / B.-G. Min and Z. H. Stachurski // Polymer. – 1993. – Vol 34. – P. 4908-4912.