MWCNTs-NH2/环氧树脂纳米复合材料压缩性能影响机理

采用1,2-环氧环己烷4,5-二甲酸二缩水甘油酯（TDE-85)、对氨基苯酚环氧树脂（AFG-90）及其混合树脂,以二氨基二苯砜（DDS）为固化剂，添加氨基化多壁碳纳米管（MWCNTs-NH₂）制备了纳米复合材料。应用非等温差示扫描量热（DSC），红外光谱（FT-IR）和力学性能测试等方法，分析了添加MWCNTs-NH₂前后，树脂体系固化反应、醚化反应与压缩性能的变化。研究结果表明，碳纳米管/环氧树脂复合材料的压缩性能与固化反应后期羟基和环氧基团之间的醚化作用有密切关系。MWCNTs-NH₂的加入阻碍了TDE-85/DDS体系固化反应后期的醚化作用，与纯树脂体系相比反应热降低了50 J/g，红外光谱中脂肪族醚键与苯环吸收峰面积比值降低了7.7%，复合材料压缩强度降低了3.2%。与之相反的是，MWCNTs-NH₂的加入促进了AFG-90/DDS体系固化反应后期的醚化作用，与纯树脂体系相比，反应热提高了80J/g，红外光谱中脂肪族醚键与苯环的吸收峰面积比值提高了13.8%，复合材料压缩强度提高了17.4%。

Modification mechanisms of compressive mechanical properties of MWCNTs-NH2/epoxy nanocomposites

Three MWCNTs-NH₂ modified epoxy resin systems have been prepared using diaminodiphenyl sulfone (DDS) cured diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate (TDE-85), n,n-diglycidyl-4-glycidyl-oxyaniline (AFG-90) and their mixture. Non-isothermal DSC, FT-IR and mechanical tests were used to analysis the changes in curing behavior, etherification reaction and compressive mechanical properties of epoxy resins with and without MWCNTs-NH₂. The results showed that the changes in compressive strength were closely related to the etherification reaction between the hydroxyl and epoxy groups. For the TDE-85/DDS system, the addition of MWCNTs-NH₂ hindered the etherification reaction, as shown by a reduction in the normalized enthalpy change (ΔH) by about 50J/g and a reduction in the ratio of absorption peak area between the aliphatic ether bond and benzene by 7.7%, resulting in the compressive strength of the composite decreasing by 3.2%. For the AFG-90/DDS system, the addition of MWCNTs-NH₂ promoted the etherification reaction, as shown by an increase of about 80J/g in ΔH and an increase in the ratio of absorption peak area between the aliphatic ether bond and benzene by 13.8%, resulting in the compressive strength of the composite increasing by 17.4%. 