柔性环氧树脂的制备及其性能研究

通过在环氧树脂（EP）的侧链接枝柔性的聚丙二醇（PPG）制备了具有较高断裂伸长率的柔性EP。利用异佛尔酮二异氰酸酯（IPDI）中2个异氰酸酯（—NCO）基团的不同活性，首先在二月桂酸二丁基锡的催化作用下将IPDI引入EP，制备出带有NCO侧基的EP；然后再与不同相对分子质量的聚丙二醇（PPG400，PPG1000，PPG2000）进行反应，得到了具有不同长度柔性侧链的改性环氧树脂（PPG-g-EP）；使用聚醚胺（D400）作为固化剂，采用万能试验机测试固化树脂的力学性能。结果表明，柔性侧链的引入可以有效地降低材料的模量，提高其断裂伸长率，其中PPG2000改性EP的断裂伸长率最高可以达到98 %。

Study on Preparation and Properties of Flexible Epoxy Resin

A type of flexible epoxy resin was synthesized by a two-step reaction, in which isophorone diisocyanate was first reacted with the hydroxyl group of epoxy resin to obtain a modified epoxy resin with the —NCO side groups and then polypropylene glycol (PPG) was grafted onto the side chains of the modified epoxy resin through the reaction between the hydroxyl groups of PPG and the —NCO groups on the modified epoxy resin to obtain polyether-grafted epoxy resin (PPG-g-EP) with different molecular weights (PPG400, PPG1000 and PPG2000). The structure of the resultant PPG-g-EP was characterized by titration and FTIR. The thermosetting PPG-g-EP was further prepared by using polyetheramine as a curing agent, and its mechanical properties were measured by a universal testing machine. The results indicated that the thermosetting PPG-g-EP with a longer PPG chain achieved higher elongation at break, and the PPG2000-modified epoxy resin gained the maximum elongation at break of 98 %.