Preparation method of magnetic micro/nano composite filler/silicon rubber heat-conducting composite material

Abstract

The invention belongs to the field of polymer-base heat-conducting composite materials, and relates to a preparation method of a heat-conducting high-polymer composite material, particularly a preparation method of a magnetic micro / nano composite filler / silicon rubber heat-conducting composite material. Magnetic nano metal particles are dispersed and compounded to the micron-sized heat-conducting filler surface to obtain a magnetic composite heat-conducting filler; by using the magnetic response caused by micro / nano compounding, an external magnetic field is utilized to regulate the orientation of the micro / nano composite filler in the silicon rubber base so as to implement orientated arrangement of the composite heat-conducting filler in the silicon rubber base, thereby preparing the heat-conducting anisotropic high-heat-conductivity silicon rubber composite material under the condition of low filling percent of the filler. Besides, the micro / nano composite filler is prepared by coating the magnetic nano metal particles on the heat-conducting filler, thereby avoiding the problems of low dispersion tendency and high aggregation tendency of the nano metal particles in the polymer base, and indirectly implementing uniform dispersion of the micro / nano particles in the polymer base.

Description

technical field [0001] The invention belongs to the field of polymer-based heat-conducting composite materials, and relates to a method for preparing a heat-conducting polymer composite material, in particular to a method for preparing a magnetic micro-nano composite filler / silicone rubber heat-conducting composite material. Background technique [0002] In recent years, with the increasing integration and miniaturization of electronic components, the resulting heat accumulation and heat dissipation have become one of the key factors restricting the reliability and service life of electronic components; Thermally conductive materials have been extensively studied to solve such problems. Polymer materials have the advantages of good electrical insulation, light weight, corrosion resistance, and easy processing, but their thermal conductivity is poor. Fillers are filled into polymer materials to improve their thermal conductivity. [0003] There are many factors that affect t...

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Problems solved by technology

[0002] In recent years, with the increasing integration and miniaturization of electronic components, the resulting heat accumulation and heat dissipation have become one of the key factors restricting the reliability and service life of electronic components; Thermally conductive materials have been extensively studied to solve such problems. Polymer materials have the advantages of good electrical insulation, light weight, corrosion resistance, and easy processing, but their thermal conductivity is poor. Fillers are filled into polymer materials to improve their thermal conductivity

[0003] There are many factors that affect the thermal conductivity of polymer materials, such as different material preparation methods, the quality of filler thermal conductivity and the level of filling, different filler shapes and sizes, different filler component ratios, and physical and chemical properties of the filler surface, etc. Both will significantly affect the thermal conductivity of the material; existing research results have shown that increasing the proportion of high thermal conductivity fillers in the composite material is conducive to the formation of a thermal network, thereby significantly improving the thermal conductivity of the material, but at the same time this method will also affect the mechanical properties of the composite material. It leads to serious problems such as a serious decline in the machinability of materials; as we all know, the key to improving the thermal conductivity of composite materials is to form a heat conduction chain or network parallel to the direction of heat flow in the system. Related studies have found that under the condition of an external magnetic field, the magnetic The filler can form many chains along the direction of the magnetic field under the action of the external magnetic field, and the direction of the chain arrangement is consistent with the magnetic field; the commonly used thermal conductive fillers are mostly ceramic fillers, metal oxides, metal nitrides or carbides. However, these Fillers, especially when added in a low amount, are difficult to form a heat-conducting network chain. The developed heat-conducting rubber generally has the defect of low thermal conductivity. Although silicone rubber, as a special synthetic rubber, exhibits excellent physical and chemical properties, it is the same Conducts heat like most polymer materials, with a very low coefficient of thermal conductivity

[0004] Chinese patent 201210528511.1 discloses a method for preparing a micro-nano hybrid filler liquid silicone rubber heat-conducting composite material. In the patent, micron-sized heat-conducting particles and nano-fibrous heat-conducting fillers are respectively added to the silicone rubber matrix, and the nanometer Fibrous fillers are oriented as connecting lines, thus forming thermal chains; as we all know, the dispersion of nanofillers has always been the central problem of polymer-based nanocomposites, and it is also the bottleneck restricting the performance of composite materials. The fibrous nanofillers added in the patent are relatively For nanoparticles, the dispersion problem is more prominent, and the dispersion problem of nanofibrous fillers is not solved in the patent

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