双氰胺固化型导电胶性能优化及作用机理研究

Performance Optimization and Interaction Mechanism of Dicyandiamide-cured Electrically Conductive Adhesives

针对双氰胺固化型环氧导电胶体积电阻率大等缺点,调查了不同结构短链有机二元酸对其导电性能的改善效果。发现在所调查的五种短链二元酸中,己二酸不仅可以改善导电胶的导电性能,同时能提高导电胶的力学性能。采用己二酸对银粉进行表面处理,通过热重、XPS、DSC等分析测试发现,己二酸不仅可有效去除银粉表面硬脂酸,同时其中一个羧酸官能团在银粉表面形成己二酸盐,其另一官能团在导电胶加热固化过程中参与固化反应,进而在银粉与环氧树脂之间形成偶联,从而提高导电胶的导电和力学性能。

Five different kinds of binary acid with short-chain were introduced to improve the electrical conductivity of the dicyandiamide-cured electrically conductive adhesives （ECA）. It was found that among the above five kinds of binary acid, adipic acid could improve both the electrical conductivity and the mechanical property of ECA. The details of the action mechanism of the adipie acid on ECA were studied. By means of TGA, XPS and DSC tests, it was found that the adipic acid could remove the stearic acid on the surface of silver powder, and one of its carboxylic acid functional group could form adipate on the surface, and the other functional group would participate the curing reaction during the heat curing process, thereby the coupling formed between silver powder and epoxy resin, thus the electrical conductivity and mechanical performance of ECA was improved.