含刚性链节和脲端基聚醚增韧剂改性环氧树脂的研究———反应活性及力学性能

STUDY ON PROPERTIES OF EPOXY RESIN TOUGHENED BY A FUNCTIONAL MESOMORPHIC POLYMER ——CURING REACTIVITY AND DYNAMIC MECHANICAL PROPERTIES

合成了一系列既含环氧丙烷聚醚（ＰＰＧ）柔性间隔基、又含刚性介晶结构单元的端脲基活性改性剂（ＬＣＥＵＰＰＧ），并对其改性环氧树脂Ｅ５１／双氰双胺（Ｅ５１／ｄｉｃｙ）体系的固化反应活性、改性剂含量对增韧体系动态力学性能及冲击性能的影响进行了研究．结果表明：ＬＣＥＵＰＰＧ的加入对固化体系具有明显的增韧作用，冲击强度提高了３～７倍；其对Ｅ５１／ｄｉｃｙ固化反应具有明显的促进作用，可使固化反应表观活化能（Ｅａ）降低５０～７０ＫＪ／ｍｏｌ、固化温度降低３０～４０℃；体系的玻璃化转变温度（Ｔｇ）略有下降，但模量基本不降低或略有升高；β转变向低温方向移动．

A series of toughening agents(LCEU PPG ) containing the polypropylene glycol(PPG) flexible space,mesomorphic unit,and reactive urea terminated group were synthesized and used to modify the epoxy resin E 51/dicyandiamine(E 51/dicy) curing system.The curing reactivity,dynamic mechanical behavior,and impact strength of the modified curing systems were investigated.The results show that the addition of LCEU PPG has improved the impact strength for 3～7 times;has accelerated the curing reaction apparently,leading to the reduction of apparent curing reaction energy ( E a) by 50～70KJ/mol and the fall of curing reaction temperature by 30～40℃.Elastic modulus are almost equal to or higher than that of the unmodified system,although T g is slightly decreased and β transition temperature is shifted to a lower temperature.