查看更多>>摘要：Epoxy resins are cross-linked polymeric materials with typically low thermal conductivity.Currently,the introduction of rigid groups in-to epoxy resins is the main method to improve their intrinsic thermal conductivity.The researchers explored the relationship between the flexi-ble chains of epoxy monomers and the thermal conductivity of the modified epoxy resins(MEP).The effect of flexible chain length on the intro-duction of rigid groups into the cross-linked structure of epoxy is worth investigating,which is of great significance for the improvement of ther-mal conductivity of polymers and related theories.We prepared a small molecule liquid crystal(SMLC)containing a long flexible chain via a sim-ple synthesis reaction,and introduced rigid mesocrystalline units into the epoxy resin via a curing reaction.During high-temperature curing,the introduced mesocrystalline units underwent orientational stacking and were immobilized within the polymer.XRD and TGA tests showed that the ordering within the modified epoxy resin was increased,which improved the thermal conductivity of the epoxy resin.Crucially,during the above process,the flexible chains of SMLC provide space for the biphenyl groups to align and therefore affect the thermal conductivity of the MEP.Specifically,the MEP-Ⅵ cured with SMLC-Ⅵ containing six carbon atoms in the flexible chain has the highest thermal conductivity of 0.40 W·m-1·K-1,which is 125％of the thermal conductivity of SMLC-Ⅳ of 0.32 Wm-1·K-1,111％of the thermal conductivity of SMLC-Ⅷ of 0.36 Wm-1·K-1,and 182％of the thermal conductivity of pure epoxy of 0.22 W·m-1·K-1.The introduction of appropriate length flexible chains for SMLC promotes the stacking of rigid groups within the resin while reducing the occurrence of chain folding.This study will provide new ideas for the enhancement of thermal conductivity of cross-linked polymeric materials.
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维普