Preparation method of micro-nanometer mixed stuffing/liquid silicon rubber heat-conductive composite material

Abstract

The invention discloses a preparation method of a micro-nanometer mixed stuffing / liquid silicon rubber heat-conductive composite material. The preparation method is characterized in that the solidified two-component liquid silicon rubber is taken as a substrate; micro-scale heating conductive particles are taken as connecting points; under an external electric field action, the nanofiber heat conductive stuffing with high length-diameter ratio is oriented to a connecting line, so that the effective heat conductive chain is formed in the silicon rubber substrate, and the heat conductive silicon rubber composite material with anisotropic heat conduction is prepared. The high heat-conductive composite material is excellent in the heat-conductive performance, low in the heat-conductive stuffing dosage, good in mechanical property, simple in the preparation technology and low in cost.

Description

technical field [0001] The invention relates to a method for preparing a heat-conducting polymer composite material. Specifically, the cured liquid silicone rubber is used as a matrix, and micron-sized heat-conducting particles are used as connection points. line, thereby forming an effective heat conduction chain in the silicone rubber matrix, and preparing a thermally conductive silicone rubber composite material with anisotropic thermal conductivity, which belongs to the technical field of polymer composite materials. Background technique [0002] With the rapid development of microelectronics integration technology, the assembly density has increased rapidly, the operating frequency of electronic components has increased sharply, and the heat generated has also increased; for every 2°C increase in the temperature of electronic components, their reliability will decrease by 10%, 50 The life at ℃ is only one-sixth of that at 25℃ (Macromolecules, 1996, 29 (10): 3376-3383); ...

AI Technical Summary

Problems solved by technology

[0003] Silicone rubber is a special synthetic rubber with silicon-oxygen bonds as the main chain, while ordinary rubber has a structure of carbon-carbon bonds as the main chain. Due to its special structure, it has low temperature resistance, high temperature resistance, and High voltage, radiation resistance, ozone aging resistance, physiological inertness, weather resistance, high air permeability, and excellent chemical inertness to lubricating oil and other media. In addition, the operating temperature range (-50°C~300°C) is wide and the elasticity is good , Good resistance to tracking and electric erosion, especially after its surface is polluted, it still has good hydrophobicity; but the thermal conductivity of unfilled silicone rubber is very poor, and the thermal conductivity is generally only 0.165 W / (m.k), The thermal conductivity can be improved by filling with thermally conductive fillers. The existing solutions to improve the thermal conductivity of silicone rubber are basically to add thermally conductive fillers to the silicone rubber matrix to achieve the purpose of improving thermal conductivity. The existing problems are: (1) The combination of resins used The viscosity of the material is relatively high, and the viscosity is even greater after adding fillers; (2) The fillers are prone to agglomeration and sedimentation, and the amount of thermally conductive filler added is limited, which affects the improvement of the thermal conductivity of the obtained material; (3) In the case of low filling amount of thermally conductive fillers , the thermal conductivity of the composite material is not high, and in the case of high filling amount, although the thermal conductivity is significantly improved, the comprehensive mechanical properties of the material decrease sharply and significantly