以硅树脂为基体材料,多层石墨为导热填料,采用旋转搅拌球磨法制备了多层石墨/硅树脂导热复合材料,研究了填料对多层石墨/硅树脂复合材料热导率、热膨胀系数(CTE)和热稳定性的影响。结果表明,多层石墨在硅树脂中分散性良好。多层石墨/硅树脂复合材料的热导率随多层石墨填充量的增加而增大,填充质量分数为45%时,热导率达到2.26W.(m.K)-1,超过此值之后热导率开始下降。随着填料的增加,多层石墨/硅树脂复合材料热膨胀系数减小。与纯硅树脂相比,多层石墨/硅树脂复合材料热稳定性高。相同填充量下多层石墨/硅树脂比SiC/硅树脂、AlN/硅树脂的热导率高得多,这说明径厚比大的片状填料更易形成有效接触和导热网链。
With silicon resin as the base matrix materials,filled with multilayer graphite,the thermal conductive multilayer graphite/silicon resin composites were prepared by using the method of rotating-mixer.The effect of filler on the thermal conductivity,coefficient of thermal expansion(CTE) and the thermal stability of the composites were investigated.Results show that the multilayer graphite in silicon resin has good dispersibility.The thermal conductivity of the composites increases with the increasing content of multilayer graphite,and it reaches 2.26 W·(m·K)-1 when the mass fraction of the filler is 45%,and it begins to decrease when the mass fraction of the filler higher than 45%.CTE decreases as the filler loading increasing.The thermal stability of the silicone resin can be effectively improved through adding multilayer graphite.With the same filler loading,multilayer graphite filled silicone resin possesses higher thermal conductivity compared to SiC and AlN filled silicone resin.It proves that the flake graphite with big radius-thickness ratio can be more likely to form thermal network and improve the thermal contact.