柔性胺改性剂对环氧树脂力学性能的影响

Influence of Flexible Amine Modifier on Mechanical Properties of Epoxy Resins

以柔性胺D230作为改性剂,用浇铸成型法制备了环氧树脂结构胶,研究了其力学性能与D230加入量的关系,并探讨了该材料的微观断裂形貌与韧性的关系。力学测试结果显示室温断裂延伸率、室温和低温冲击韧性随D230含量的增加而增加,表明D230对环氧树脂产生有效的增韧作用。当D230加入量为21%(质量分数)时,室温拉伸强度和弹性模量最大,分别为85.44MPa和3.22GPa,当继续增加D230的含量时,二者则呈降低的趋势。对拉伸断面形貌进行扫描电子显微(SEM)分析显示,随着D230含量的增加,断口形貌越粗糙,表明抗开裂能力增加,这与高断裂延伸率和高冲击韧性的结果一致。热分析实验结果显示,体系的玻璃化温度(Tg)随着D230含量的增加而降低。

Epoxy resin structural adhesives modified by a flexible amine （D-230） were prepared by casting molding method. Dependence of the mechanical properties of epoxy resins on the flexible amine content was studied. The impact fracture toughness was discussed in terms of fracture surface fractography. The results showed that the fracture elongation at break at RT and the impact toughness at both RT and 77K increased with the increasing D-230 content, which demonstrated that the toughness of epoxy resin could be improved effectively by the addition of D-230. When the D-230 content was 21%（mass fraction）, the epoxy resin at RT exhibited the highest tensile strength and Young＇s modulus, 85.44 MPa and 3.22GPa, respectively; afterwards, both the tensile strength and Young＇s modulus decreased with the increase of D-230 content. SEM analysis of tensile fracture surfaces showed that the fractography tended to be irregular with the addition of flexible amine, indicating that the crack-resisting ability was improved. This result was consistent with the observation of higher fracture elongation and higher impact toughness. Thermal analysis of specimens showed that the glass transition temperature （Tg） decreased with increasing the D-230 content.