端羟基液态丁腈橡胶对室温固化环氧树脂热学和电学性能的影响

Thermal and Electrical Properties of Room Temperature Cured Epoxy Resin Modified by Hydroxyl-terminated Liquid Nitrile Butadiene Rubber

采用液态橡胶对环氧树脂进行增韧在电力设备和电子封装领域都有一定的应用,以往的研究对增韧后热学和电学性能的变化关注较少。该文采用端羟基液态丁腈橡胶(hydroxyl-terminated liquid nitrile rubber,HTBN)对一种室温环氧树脂进行改性,并对其热学性能和电学性能进行测量和分析。HTBN加入后形成的两相界面阻碍了声子运动,使得导热率和热扩散系数下降。采用电模量的形式分析HTBN对环氧树脂松弛过程的影响机理,发现HTBN在基体中引入2个松弛过程,使介电损耗在低温和玻璃化转变温度附近区域陡然增大。低温区域主要是由HTBN分子的a转变引起,而玻璃化转变温度附近主要由界面极化引起。高温电导在电模量形式下对应的松弛峰强度随HTBN含量先减小后增大,弛豫时间符合Arrhenius方程,拟合得到的表观活化能随HTBN含量先增大后减小。该文中对环氧树脂增韧体系热学和介电性能的分析有助于此类配方体系的应用和设计。

Toughening epoxy resin with liquid rubber has been applied in the field of power equipment and electronic packaging. Previous studies paid little attention to the thermal and electrical properties. In this paper, hydroxyl-terminated liquid nitrile rubber(HTBN) was used to toughen a kind of room temperature cured epoxy resin, and the thermal and electrical properties were measured and analyzed. The interface formed between HTBN and epoxy matrix hinders the phonon movement and decreases the thermal conductivity and thermal diffusivity. The influence mechanism of HTBN on the relaxation process of epoxy resin was analyzed in the form of electrical modulus. HTBN introduces two relaxation processes into the matrix, which makes the dielectric loss increase sharply near the low temperature and glass transition temperature. The relaxation peak introduced in the low temperature region is caused by the a transition of HTBN molecules, while the relaxation peak near the glass transition temperature is mainly caused by the interfacial polarization. The relaxation peak intensity of high temperature conductivity in the form of electric modulus increases first and then decreases with the content of HTBN. The relaxation time accords with Arrhenius equation, and the apparent activation energy first increases and then decreases with HTBN content. The analysis of thermal and dielectric properties of epoxy toughening system in this study is helpful to the application and design of this kind of formulation system.