Study On Migration Characteristics Of Elastomer Thermal Interface Materials And Optimum Modification Of Thermal Conductive Filler

With the continuous improvement of science and technology and living standards, the requirements for the performance of thermal interface materials are getting higher and higher. The migration characteristics, which have been mainly focused on the field of aviation and vacuum, are gradually entering into daily life. Migration refers to the phenomenon that the small molecular oil in the thermal interface material of the elastic body escapes from the interior to the outside of the material. The migration of the material directly affects the maintenance of the vacuum and the cleaning of the sensitive surface of the optical component. The worse migration characteristics, the more easily small molecule escapes from material, and optical components are more likely to fail. . In addition to migration characteristics, the thermal properties of thermal interface materials have been the focus of attention. The coefficient of thermal conductivity has been an important index to measure thermal interface material. From two aspects: migration characteristics and thermal conductivity,the following contents are studied:1. After the failure of the elastomeric thermal interface material(ETIM) in optical components, the optical head may be contaminated and affect the normal use of the device. In view of this kind of case, we studied the structure and composition of ETIM, and the failure history of ETIM is studied from the two aspects of oozing and volatilization. The migrated substances were analyzed by FTIR, GPC, the gas chromatographic mass spectrometry(GC-MS), and contate angle analysis. In particular, GC-MS was used to analyze the molecular structure of the collected exudates and volatile condensates, and successfully established a research method of qualitative and quantitative research to explore the species and content of migration by GC-MS.2. Three kinds of spherical alumina with different particle size were selected and filled into the two-component silicone rubber matrix to prepare ETIM. When the total filling amount of the three fillers is constant, the influence of different ratio on the thermal conductivity of the composites is investigated. Orthogonal test method is used to design the experimental scheme and the simulation experiment is as auxiliary explanation. The results show that when the amount of Ax75-125 with an average particle size of 75μm is 55wt%, the amount of Aw45-70 with an average particle size of 45μm is 20wt%,and the amount of Ax3-32 with an average particle size of 5 μm is 25wt%, the thermal conductivity of the silicone rubber thermal interface composites is 4.61W / (m·K).3. The surface modification and interface optimization of conductive filler has been used as a way to improve the thermal properties of composite materials. In this paper, spherical alumina was coated with catechol and tetraethylenepentamine as modifier (Abbreviation: Phenol Amine Modified,PAM), and the modified filler was grafted with silane coupling agent KH570(γ-methacryloyloxytrimethoxysilane) modified. The results show that the optimum reaction condition is: the content of the filler was 10g/100g deionized water, the reaction temperature was 60°C, the Ph value was 9.5, and the reaction time was 6 h. After phenolic modification, KH570 grafting effect is better, are effective to improve the surface properties of alumina powder.