| The rapid development of technology has put forward higher requirements on the comprehensive performance of materials.Single-performance materials have been unable to meet the application of special fields.It is an effective method to solve the problem by combining the different polymerization mechanism to obtain the performance-controlable hybrid materials.DADGEBA is a special polyfunctional epoxy resin containing both allyl and epoxy groups.The special structure of DADGEBA gives it the ability to dual cure.In this paper,the UV-thermal dual curing system of DADGEBA was designed and prepared.The UV-curing consists of a thiol-ene click reaction,and the thermal curing is composed of the thermal reaction of the epoxy group.The curing behavior of the dual curing system and the thermodynamic and mechanical properties of the cured products were studied.Then,the dual curing system was used in the bonding of styrene butadiene rubber(SBR)and metal,and the bonding effect is very good.Specific research work is as follows:1.The DADGEBA UV-thermal dual curing system was prepared by using PETMP as mercapto compounds,1173 as photo initiator and D230 as thermal curing agent.The reaction process was characterized by RT-FTIR and FT-IR,and the results showed that the system could react according to the mechanism of UV-thermal dual curing.The presence of epoxy thermal-curing system does not affect the efficient UV-curing reaction of thiol-ene,and the epoxy groups do not react during the UV-curing reaction.The conversion of thiol and double bonds can reach more than 90%.2.The mechanical properties and thermodynamic properties of DADGEBA cured materials are also comparatively study.The results show that the Tg of DADGEBA UV-thermal dual curing product is higher than that of pure UV-curing and thermal-curing,and the thermal stability is equivalent to thermal-curing,and the mechanical properties combine the advantages of UV-curing and thermal-curing,with a tensile strength equal to that of the thermal-curing,and the elongation at break is 2.5 times that of the thermal-curing materials.In addition,the effects of different functional thiols on the thermodynamics and mechanical properties of DADGEBA/thiol/1173/D230 UV-thermal dual curing system were investigated.It was found that with the increase of thiol functionality,the crosslink density of the system increased,the Tg of the cured product increased,the thermal stability increased,the tensile strength increased,and the elongation at break decreased.3.DADGEBA/PETMP synergistic photo-thermal dual curing system was prepared by using 1173 as photoinitiator and TEA as thermal accelerator,and compared with D230 system.The network crosslink density of TEA system is extremely large,the segment is packed closely,showing a higher Tg,excellent thermal stability and high tensile strength.The D230 system exhibits better network integrity and better toughness.4.We described here functionalization of surface of SBR via thiol-ene click chemistry using UV-photo grafting methodology and investigation of its adhesion with#45 steel.PETMP and 1173 were used as monomer and initiator,respectively.The surface composition of grafted SBR was examined by infrared attenuated total reflection(FTIR-ATR)and X-ray Photoelectron Spectroscopy(XPS)analyses and the results indicate that PETMP had been successfully grafted on the surface of SBR through the active groups of PETMP(sulfydryl and carbonyl).Water contact angle test proved that the polarity and wettability of the surface were improved as well.The smooth coatings and polymerized PETMP existing on the surface of SBR were characterized by scanning electron micrographs(SEM).Atomic force microscopy(AFM)results showed that many peaks were formed on the SBR surface after grafting.The adhesion strength of grafted SBR and#45 steel were analyzed by tensile-shear test. |
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