二氧化硅改性环氧树脂胶黏剂性能研究

Study on the Properties of Epoxy Resins Modified by Nano-Silica

采用聚氨酯增韧环氧树脂,并利用有机化的纳米SiO2为改性剂制备纳米改性环氧树脂胶黏剂.利用扫描电子显微镜(SEM)观察无机纳米粒子在聚合物基体中的分散性及复合材料的断面形貌,结果表明无机纳米粒子在复合材料中分散性良好,而且聚氨酯在环氧树脂基体中形成了"孔洞结构".采用电子拉力机、TGA以及介电谱仪等方法测试了复合材料的力学性能、热稳定性能和介电损耗、介电常数等性能.结果表明,纳米SiO2在一定的掺杂量下有利于力学性能的提高,当质量分数为2%时,材料的剪切强度和弹性模量比掺杂前分别提高173%和95%;热分解温度也有一定程度的提高,当掺杂2wt%时,热分解温度比掺杂前提高8.1℃;介电常数(ε)的变化表现为:随频率增加而下降,随无机组分增加而增大;介电损耗(tanδ)则得到了明显的改善,在频率1kHz时介电损耗相对较好.

Organic precursor of EP/PU was prepared by epoxy resin which was polyurethane toughened,and then modified epoxy resin adhesive was synthesized using nano-silica as modifier.Microstructure of composite materials was observed by scanning electron microscopy（SEM）.The results showed that the inorganic phase had well dispersed in the polymer matrix,and the polyurethane has formed ＂the hole structure＂ in the epoxy resin substrate.The mechanical properties,thermal stability and dielectric loss,dielectric constant of composites were investigated by electronic tensile machine,TGA and dielectric spectrum analyzer.The results indicated that doping of appropriate amount of nano-silica could improve mechanical properties,the shear strength and elastic modulus of 2% SiO2/EP-PU were increased 173% and 95%,respectively,than pre-doping of composite.Thermal decomposition temperature（Td） was increased,Td of 2%SiO2/EP-PU was increased 8.1℃ than pre-doped of material.Dielectric constant（ε） was as follows： decreased with the increase of frequency,but increased with the increase of inorganic component;dielectric loss（tanδ） was improved obviously,and the frequency 1kHz is better.