Design And Research Of Uv-thermal Dual Cured Cycloaliphatic Epoxy Resin System

Using UV-thermal dual curing technology,cycloaliphatic epoxy resin（CAE）can be cured rapidly in the photopolymerization stage,and then cured by heating to improve the quality of products.The epoxy resin materials with high mechanical properties,good electrical insulation properties and good bonding properties can be obtained.However,the cycloaliphatic epoxy resin polymer usually exhibits poor toughness due to their highly cross-linked three-dimensional network structure,as well as low thermal conductivity defects in the resin matrix itself.Both of these two aspects have attracted the attention of researchers.According to brittleness and low thermal conductivity of cycloaliphatic epoxy resin,nano cellulose and boron nitride nano sheets were used for its modification in this paper.The main research contents are as follows:（1）The cycloaliphatic epoxy matrix toughness composites were prepared by UV-thermal dual-curing technology and nanocrystalline cellulose（NCC）which has the characteristics of green degradable and excellent mechanical properties as reinforcing agent.The results show that the addition of NCC is beneficial to improve the conversion of epoxy resin and the impact toughness of the composites.The study opens up the possibility of large scale use of active hydroxyl fillers for UV-thermal dual cured modified cycloaliphatic epoxy composites.（2）A novel nano-modified filler（NCC-Ca）was prepared by ion coordination effect between Ca²⁺and nanocrystalline cellulose（NCC）,and the NCC-Ca nano-modified fillers were applied to the cycloaliphatic epoxy composites.The results show that the polymer network is formed through dynamic metal ion coordination between Ca²⁺and the active hydroxyl groups on the surface of nanocrystalline cellulose.The impact strength and bending strength of NCC-Ca/CAE composites were improved.In this study,the cycloaliphatic epoxy matrix toughness composites were obtained by covalent and metal ion coordination double cross-linking network design.（3）A new kind of nano hybrid heat conduction filler（BNNS/NCC-Ca）was prepared by self-assembly of modified nanocrystalline cellulose（NCC-Ca）and boron nitride nano sheet（BNNS）which were stripped by alkaline ultrasonic.The composite material was prepared by filling BNNS/NCC-Ca into CAE matrix.The results showed that NCC-Ca was successfully attached to the surface of BNNS.The thermal conductivity of BNNS/NCC-Ca/CAE composite that was supported by aerogel is up to 0.47 W/m K,which is 2.83 times of pure epoxy and 1.71times of BNNS/NCC-Ca/CAE composite that prepared by disordered mixing under the same mass.In this study,by constructing three-dimensional BNNS/NCC-Ca network,the composites with good thermal conductivity were obtained.