Effect of Reactive Diluent on Epoxy Resin for Self-healing

Cracking is one of the most common forms of concrete pavement damage. The self-healing technology of microcapsules is an effective way to inhibit the formation and development of cracks. The existing curing agent has the problems of high-temperature curing, difficult storage and toxicity at present. Based on the curing system of epoxy resin (E-51/polymercaptan), the dilution and curing effects of two active diluents on E-51 were studied to meet the self-healing requirements of micro-cracks under room temperature and without manual intervention. The viscosity of alkyl (C12-C14) glycidyl ether/ethylhexyl glycidyl ether (AGE/EGE) mixed with E-51 was analyzed by viscosity test. Then, the mechanical properties of curing products were tested by tensile shear strength and hardness test. The effects of different diluent types and contents on the mechanical properties of cured products were also explored. Besides, the thermal stability and thermomolecular dynamics characteristics of curing products with varying dosages of two active diluents were analyzed by thermogravimetric and differential scanning calorimetry. Result of viscosity, mechanical properties and thermal dynamics characteristics shows that the dilution effect of EGE on E-51 is better and the curing promotion effect is stronger with the same dosage. Although the energy required in the reaction process is 11% more than the dosage of AGE, the feature of sudden release of energy in the polymercaptan curing system can meet the curing energy requirements of EGE. Therefore, it is suggested to select 20% EGE as the active diluent of the E-51/polymercaptan curing system.