Polymerization mechanisms and curing kinetics of novel polymercaptan curing system containing epoxy/nitrogen

Abstract

ABSTRACT:The bis[3-(2,3-epoxypropylthio)phenyl]-sulfone (BEPTPhS)/trimercaptothioethylamine (TMTEA) system has a self-catalytic effect and can cure without any other accelerator. The curing kinetics of the BEPTPhS/TMTEA system was studied by means of the dynamic and isothermal differential scanning calorimetry method. The dynamic kinetic parameters were calculated with the aid of the Kissinger and Ozawa methods. The kinetic reaction mechanism in the isothermal reaction of BEPTPhS/TMTEA was shown to follow autocatalytic kinetics. The isothermal kinetic parameters, including k 1 , k 2 , m, and n, from the model proposed by Kamal were determined by fitting the experimental data; a good description of the curing kinetics was obtained, although deviations were observed at low conversions. The Arrhenius kinetic analysis indicated that the activation energy decreased with the increase of the reaction conversion, which indicated a change of the reaction mechanism. The isothermal kinetic analysis and Arrhenius kinetic analysis both demonstrated that the catalytic effect of the nitrogen atom in TMTEA predominated at low conversions and the autocatalytic effect predominated at high conversions.

Comparison of the curing kinetics of a DGEBA/acid anhydride epoxy resin system using differential scanning calorimetry and a microwave‐heated calorimeter

“…Equation (1) can be modified to give Hence during the curing of an epoxy resin, the reaction rate is only a function of temperature at any given conversion and the plot of ln d α/ dt against 1/ T should be a straight line with slope − E / R 18…”

Synthesis of Two Novolac Type Epoxy Resin Curing Agents and their Application

“…The curing reaction kinetic parameters were evaluated with a multiple-heating-rate method by the determination of the exothermic peak temperatures (T p ) at different heating rates. In practice, two convenient multiple-heating-rate methods are common used [14] . One is the maximum reaction rate (dα/dt) method proposed by Kissinger [15] , which is based on the fact that T p varies with the heating rates.…”