Design And Study Of Epoxy Resin UV-heat Dual Curing Systems

Epoxy resin cationic UV curing reaction has the advantages of anaerobic polymerization inhibition, low curing shrinkage, post curing behavior and strong adhesion to the substrate, which has attracted wide attention. However, the epoxy cationic curing film is brittle due to its high crosslinking density, which limits its applications. In this article, a cationic curing system of epoxy was designed and studied as well as its toughening modification by DADGEBA/Thiol UV-heat dual curing system. The main conclusions are as follows:1. Five kinds of cationic UV-heat dual curing system of epoxy were designed, which were TTA-26, TTA-21, E-44, E-51 and DER332. RT-FTIR tests showed that the conversion of epoxide of alicyclic epoxy resin TTA-26 and TTA-21 was higher than that of DGEBA, E-44, E-51 and DER332; the conversion of epoxide was higher when the monomer molecular chain was longer of the same kind of epoxy resin. The study of post curing of E-51 showed that when the temperature was certain, the conversion of epoxide got higher as the UV irradiation time was longer, and when the UV irradiation time was certain, the conversion of epoxide got higher as the post curing temperature grew. Thermal performance tests showed that the glass temperature and thermal stability of E-44, E-51 and DER332, the DGEBA system, was greater than that of TTA-26 and TTA-21, the alicyclic epoxy resin system. The cationic curing film of TTA-26 and TTA-21, the alicyclic epoxy resin system has better thermal degradation. The glass temperature was lower when the monomer molecular chain was longer of the same kind of epoxy resin. Mechanical properties tests showed that the tensile strength of TTA-26, TTA-21, E-44, E-51 and DER332 were 46MPa,44MPa,56MPa,52MPa and 50MPa respectively, and the breaking elongation of them were 4.8%,4.8%, 2.9%,2.5% and 2.3% respectively, which proved that the epoxy cationic curing film has higher tensile strength and lower breaking elongation.2. Three kinds of UV-heat dual curing system were designed, which were DADGEBA/EGBMP, DADGEBA/TMTP and DADGEBA/PETMP. RT-FTIR tests showed that the thiol and C=C conversion of the systems can reach 96% and 89% when the UV irradiation time was 10 min. After 10min-UV-irradiation, the systems were heated for 6 hours at 120?, and then the epoxide conversion of DADGEBA/EGBMP, DADGEBA/TMTP and DADGEBA/PETMP was 88%,82% and 76% respectively. The DMA tests showed that the glass temperature and storage modulus of UV-heat dual curing films were DADGEBA/EGBMP<DADGEBA/TMTP<DADGEBA/PETMP. The static mechanical test showed that the tensile strength of DADGEBA, DADGEBA/EGBMP, DADGEBA/TMTP and DADGEBA/PETMP UV-heat dual curing films were 51 Mpa,16 MPa,43 MPa and 76 MPa, the breaking elongation of them were 2.6%,6.5%,5.9% and 5.5%. This proved that adding PETMP in DADGEBA can not only increase the material elongation at break but also improve their tensile strength, which realized the toughening of the DADGEBA cationic curing system.