Effect of synergistic environmental conditions on thermal properties of a cold curing epoxy resin

This study presents an investigation addressing the effect of environmental conditions on the thermal properties of a cold curing epoxy resin used in repair and strengthening of masonry structures. The exposure conditions consist of laboratory indoor conditions (IC), long-term water immersion (WI), hygrothermal exposure (HG) and outdoor real exposure conditions (OC). The changes in the glass transition temperature, Tg, relaxation enthalpy and enthalpy peak temperature are monitored with Differential Scanning Calorimetry (DSC). Different measurement techniques for obtaining the Tg from DSC curves are also presented and discussed. The results showed a reduction of Tg in WI tests due to plasticization, which reversed at long-term periods. In HG conditions, post-curing of epoxy resin led to an increment of Tg. It was observed that the changes of Tg in OC conditions in the studied environment have a good correlation with the moisture absorption level and the obtained results from WI tests.