Preparation And Properties Of Liquid Crystal Epoxy Based Thermal Electronic Packaging Materials

Epoxy resin is one of the most commonly used materials in electronic packaging.However, neat epoxy resin is not suitable for high-performance applications because of its low thermal conductivity, poor thermal stability and low loss modulus. With the rapid development of science and technology, great changes have taken place in electronic industry.The development of electronic appliances with miniaturization high power and integration need the packaging materials with higher performance. Modification of epoxy resin with crystalline polymer, and the mixture of inorganic particles as the heat conductive fillers is one of development directions,which is important and significant for improving thermal stability and mechanical properties of materials and its application in electronic packaging.In this paper, liquid crystalline epoxy resin（EP2） was synthesized by 4-hydroxy-benzoic acid、4,4’-Dihydroxybiphenyl、epichlorohydrin.FTIR and NMR results show that the polymer is target compound.POM analysis results show that the EP2 presents a liquid crystal structure in 145-175℃.This suggests that EP2 is liquid crystalline polymer, which has good liquid crystal structure under a certain temperature.EP2-is used to modify epoxy resin. The results show that the thermal conductivity is0.36w/（m?K）,which is 3 times of neat epoxy resin.Al₂O₃ is one of the most commonly used heat conductive fillers.Al₂O₃ particles have strong self-aggregation tendency for their huge specific surface area and large surface energy,which affects the products in performance directly. In order to solve the problem, KH550 and IPDI are needed to modify Al₂O₃.FTIR results show that the chemical reaction between KH550、IPDI and the Al₂O₃ happened. The dispersibility of modified Al₂O₃ is better than that of the unmodified Al₂O₃,and the dispersibility of KH550 modified Al₂O₃ is better than that of the IPDI modified Al₂O₃.The compatibility of modified Al₂O₃ with matrix is better than that of the unmodified Al₂O₃.This is because the modifying agent work as link bridge,which results that IPDI is better than the KH550.Al₂O₃ 、 KH550-Al₂O₃ 、 IPDI-Al₂O₃ with EP2/epoxy resin was blended to producing Al₂O₃/EP2/epoxy resin、KH550-Al₂O₃/EP2/epoxy resin and IPDI-Al₂O₃/EP2/epoxy resin. The study finds that the storage modulus of the composite with modified Al₂O₃ is higher than that of the unmodified Al₂O₃,and the composite with IPDI modified Al₂O₃ is higher than that composite with KH550 modified Al₂O₃.The glass transition temperature of composites decreases with the increasing of the content of Al₂O₃. Loss modulus, impact strength and tensile strength of composites rise with the increasing of the content of Al₂O₃, whether the filler is modified but with the same mass fraction of Al₂O₃, tensile strength of modified Al₂O₃ composites is higher than the unmodified Al₂O₃ composites. Thermal conductivity of composites rises with the increasing of the content of Al₂O₃,whether the filler is modified,but modified Al₂O₃ composites is higher than the unmodified Al₂O₃ composites, thermal conductivity of IPDI-Al₂O₃/EP2/epoxy resin is higher than KH550-Al₂O₃/EP2/epoxy resin.Thermal conductivity of IPDI-Al₂O₃/EP2/epoxy resin is 1.03W/（m?K）,which is 5.7 times of neat epoxy resin.