Preparation And Thermophysical Properties Of Epoxy Resin Based Thermal Interface Materials

With the continuous development of electronic integrated circuits and the trend toward the development of electronic products,people have put forward higher requirements for the performance of electronic components in the fields of medicine,aerospace,materials,and machinery.The rapid increase in the integration density of electronic components has led to a high density of heat dissipation problems.In order to ensure the stable and stable operation of the heating element,a large amount of heat must be transferred in a timely and efficient manner,and its operating temperature should be maintained within an appropriate range.Therefore,the development of high thermal conductivity interface composites with excellent overall performance has become a hot topic of research.In this paper,aluminum oxide?Al₂O₃?,multi-walled carbon nano-particles?WCNTs?and silver nanoparticles loaded graphene were used as thermal conductive fillers.Bisphenol A epoxy resin CYD128 was used as matrix to prepare epoxy-based interfacial composites.Thermophysical properties were studied.The main contents are as follows:?1?A two-step modification of alumina using silane coupling agent KH560 and low molecular polyamide PA650 was performed,and the resulting modified alumina particles were used as a thermally conductive filler to prepare an epoxy resin-based composite material.Fourier infrared spectroscopy showed that the epoxy and amino groups were successfully grafted on the surface of alumina particles.At a loading of 20 wt%,the thermal conductivity enhancement effect of the grafted amino functionalized alumina particle composite relative to the unmodified alumina particle composite reached a maximum of 158.5%,whereas the grafted epoxy functionalized alumina The reinforcing effect of the particle composite with respect to the unmodified alumina particle composite also reached a maximum of 121.5%at a loading of 20%by weight.Through 10?m and40?m alumina particles filled with epoxy resin,under the same mass fraction conditions,it is easier to form heat conduction networks that are in contact with each other than small particle size fillers and large particle size fillers.The use of two particle sizes of alumina is better than using a single particle size.When the mass ratio of 40 um to 10 urn alumina particles is 4:1,the thermal conductivity of the resulting composite reaches the highest.?2?Surface modification of carbon nanotubes with surfactant sodium dodecylbenzene sulfonate,and carbon nanotubes modified with SDBS can better improve the dispersion and stability of carbon nanotubes in the matrix.The effect of increasing the loading of carbon nanotubes on the thermal conductivity of composites under different temperature conditions is different.When the temperature is 25°C and 30°C,the addition amount of carbon nanotubes is between 0.5wt%and 2.5wt%.The thermal conductivity of the composite increases linearly with the increase of the content of the thermally conductive filler;when the content of the thermally conductive filler is 2.5 Between wt%and 4.0wt%,the increase in thermal conductivity of the composite material did not increase significantly with the increase of the thermal conductive filler,ie,the thermal conductivity increased the plateau phenomenon.As the thermal conductivity test temperature rises,the appearance of the plateau phenomenon shifts with increasing temperature.?3?Surface-modified carbon nanotubes?5 to 15?m?and alumina particles?10?m?were used as composite thermal conductive fillers.Both can be uniformly dispersed in the resin matrix,and there is no accumulation and aggregation of the thermally conductive filler.The carbon tube and the alumina particles contact each other,and the linear carbon nanotubes act as a bridge between the alumina particles,linking the originally isolated alumina particles together to form an efficient heat conduction network.When 2.5wt%carbon nanotubes were added to epoxy resin matrix,the thermal conductivity of alumina composites with different mass fractions increased with the increase of alumina particles content.The test temperature rose to 40⁶0°C,and the thermal conductivity of the composite material obtained by adding 40wt%alumina particles and carbon nanotubes compounded was 30wt%,and the thermal conductivity of the composite improved by about 17%.The thermal conductivity of the composites prepared from the composites of carbon nanotubes and alumina particles with two kinds of thermal conductive fillers is higher than that of the composites with only alumina particles.The thermal conductivity enhancement effect of adding carbon nanotubes reaches a maximum of 177.8%when the alumina particle content is 5 wt%.?4?A graphene nanosheet loaded with silver nanoparticles was prepared by a"mixed-heated"method.The average size of silver nanoparticles increases with the silver loading.According to the XRD pattern analysis,the Ag-GNS sample was prepared,the conversion of salt and metal was basically completed,and the GNS structure was well preserved.The thermal conductivity values of the epoxy-based interface materials with Ag-GNS as the thermally conductive filler increase higher than the thermal conductivity values using the GNSs as the thermal conductive material.The greater the loading of silver nanoparticles on the GNS surface,the higher the thermal conductivity value of the epoxy-based thermal interface material.Loaded silver nanoparticles can effectively prevent graphene sheet agglomeration.