Exploring the Influence of Different Types of Toughening Agents on the Thermodynamic Properties of Epoxy Polymers

The physical and chemical properties of epoxy resin cured products prepared with different types of toughening agents show significant differences. In order to study the influence of molecular structure of different toughening agents on the electrical properties of cured epoxy resin, three kinds of epoxy polymers were prepared by the reaction of three commonly used toughening agents dibutyl phthalate (DBP), polypropylenglycol diglycidyl ether (PPGDGE), and phenol-formaldehyde resin F-51 with E-51 epoxy resin. The results show that when the toughening agent is 10wt% PPGDGE, the impact strength of the epoxy polymer is the highest, at 28.02 kJ/m2, which is 41.2% higher than that of unmodified epoxy resin. Based on Materials Studio, the free fraction volume and root mean square displacement of the cured molecules of these three different structures of epoxy resin were analyzed. The study found that when 10wt% PPGDGE was used as the toughening agent, the free volume proportion and mean square displacement displacement of the material were minimized. The simulation results showed that the toughening effect of epoxy resin was PPGDGE > F-51 > DBP, which is consistent with the experimental results.