Electrical, Thermal and Mechanical Properties of Epoxy/CNT/Calcium Carbonate Nanocomposites

Epoxy/CNT and epoxy/CNT/calcium carbonate nanocomposites were produced via in situ polymerization assisted by ultrasonication without solvent and electrical, mechanical, thermal and thermomechanical properties of nanocomposites were evaluated. Epoxy/CNT presented very low percolation threshold, near 0.05 wt % and nanocomposites with higher contents of CNT presented further increase in electrical conductivity. The addition of calcium carbonate in epoxy/CNT nanocomposites increased the electrical conductivity, due to volume exclusion phenomena. Regarding thermal properties, due to the low content of the CNT and calcium carbonate no changes in glass transition (Tg) were observed. DMA results showed no significant changes in thermomechanical properties, once the contents of CNT and calcium carbonate are below stiffness threshold, however an increase of flexural modulus by adding CNT and calcium carbonate was observed.

本研究通过无溶剂超声辅助原位聚合法制备了环氧/碳纳米管（CNT）以及环氧/碳纳米管/碳酸钙纳米复合材料，并对该类纳米复合材料的电学、力学、热学及热机械性能开展了表征与评估。环氧/碳纳米管复合材料具备极低的渗流阈值，接近0.05 wt%；碳纳米管添加量更高的该类复合材料，其电导率亦进一步提升。在环氧/碳纳米管复合材料中掺入碳酸钙可提升其电导率，该现象源于体积排斥效应。针对热学性能，由于碳纳米管与碳酸钙的添加量较低，未观测到玻璃化转变温度（glass transition temperature, Tg）出现显著变化。动态力学分析（Dynamic Mechanical Analysis, DMA）结果表明，当碳纳米管与碳酸钙的添加量低于刚度阈值时，该纳米复合材料的热机械性能未出现显著变化；但通过掺入碳纳米管与碳酸钙，可有效提升其弯曲模量。