生物基氢化香豆素增韧环氧树脂的制备及性能

通过生物基原料氢化香豆素(DHC), 在铬(Ⅲ)络合物和氯化铵复合物协同催化作用下, 与环氧醚类物质交替共聚, 获得一类三维网状聚合物, 进而与环氧树脂(EP)单体在固化过程中构建双网络结构, 实现有效的应力传递和外部能量吸收, 达到对环氧树脂增韧增强的效果. 凝胶渗透色谱结果表明, DHC基网络(DHC-net)分子量随反应时间延长而增加. ¹H NMR证实了合成的DHC-net分子结构. 同时, 考察了环氧树脂的热力学及力学性能, 发现DHC-net与环氧树脂基体具有良好的相容性; 改性后的环氧树脂断裂伸长率比纯环氧树脂有大幅提高; 拉伸与冲击测试显示, DHC-net含量小于30%时, 改性后环氧树脂的拉伸强度和抗冲击强度均比纯环氧树脂有大幅提高.

Preparation and Properties Characterization of Biobased Dihydrocoumarin Toughened Epoxy Resin†

A kind of 3D polymeric network, obtained through alternating copolymerization of dihydrocoumarin(DHC) and epoxides with the aid of chromium(Ⅲ) complexes and bis(triphenylphosp-hosphoranylidene) ammonium chloride(PPNCl) catalysts, was introduced into the diglycidyl ether of bisphenol A(DGEBA) matrix to build a double network structure. This structure can achieve an effective stress transfer and energy absorption for the DGEBA toughness. The gel permeation chromatography(GPC) results showed that the molecular weight of DHC-net increased with the react time. DHC-based network(DHC-net) structure was confirmed via the ¹H NMR spectrum. Moreover, the chemical structures of epoxy resin(EP), DHC-net and EP/DHC-net double networks were confirmed via the FTIR spectra. DMA, DSC and TGA tests indicated that a good compability between the DHC-based network and the DGEBA matrix. Mechanical test showed that an obvious increase in the elongation at break was achieved after the DHC-based network was introduced into the DGEBA matrix. Furthermore, compared to the neat DGEGA resin, remarkable improvements in tensile and impact strength were found after the introduction of DHC-based network with content no higher than 30%(mass fraction) into the DGEBA matrix.