含柔性链段环氧树脂的合成与性能

Synthesis and properties of epoxy resin containing flexible segments

采用甲苯二异氰酸酯(TDI)与聚丙二醇(PPG)合成端异氰酸酯基聚醚(ITPs),利用ITPs与环氧树脂反应,合成了含柔性链段环氧树脂。使用FT-IR、DSC、SEM对产物结构及改性后固化物的玻璃化转变温度(T)和断面形貌进行了表征,并探讨了柔性链段对提高环氧树脂g固化物粘接性能和韧性的作用机理。结果表明,ITPs可与环氧树脂链上的仲羟基反应,生成含柔性链段环氧树脂。少量ITPs的引入可阻碍固化物中分子内氢键的产生,使粘接性能提高,同时ITPs的引入可钝化裂纹的失稳扩展,使固化物韧性提高,但拉伸强度略有降低。

The isocyanate-terminated polyethers（ITPs） were synthesized with toluene diisocynate （TDI） and polypropylene glycol（PPG）, and then the epoxy resin（EP） with flexible segments was synthesized from the ITPs and EP. The structure of reaction product, the Tg and fracture surface morphologies of the cured modified-epoxy resin were respectively characterized by FT-IR, DSC and SEM. Moreover, the mechanism of increasing of the bonding properties and toughening for the epoxy resin with the flexible segments was discussed. The results showed that the ITPs was able to react with the secondary hydroxyl groups of EP to produce the epoxy resin containing the flexible segments. Introducing small amount of ITPs could impede intramolecular H-bond formation of the cured modified-epoxy resin, resulting in enhancing the bonding properties. Meanwhile, introducing ITPs could blunte the crack extension and increase the toughness of the cured, but the tensile strength slightly declined.