聚氨酯改性TDE-85/MeTHPA树脂的固化反应机理及动力学研究

Curing kinetics and mechanism of TDE-85/MeTHPA epoxy resin modified by polyurethane

以聚醚二元醇、甲苯二异氰酸酯为原料,合成了聚醚型聚氨酯预聚体(PUP)。采用该预聚体、扩链剂1,4-丁二醇、交联剂三羟甲基丙烷对TDE-85/甲基四氢邻苯二甲酸酐(MeTHPA)环氧树脂体系进行改性,通过示差扫描量热法与红外光谱法分析,探讨了聚氨酯(PU)改性环氧树脂体系固化反应机理及固化反应动力学特征。固化反应机理研究表明,TDE-85与MeTHPA之间的固化反应形成环氧聚合物网络Ⅰ,1,4-丁二醇及三羟甲基丙烷同PUP进行了扩链、交联反应形成了PU聚合物Ⅱ。异氰酸酯基同环氧基反应,使得聚合物Ⅰ与聚合物Ⅱ形成了接枝化学键。固化反应动力学研究表明,PU的加入可明显降低环氧树脂固化反应的表观活化能,活化能由TDE-85/MeTHPA树脂体系时的83.14 kJ/mol降至PU改性后的67.91 kJ/mol。

The TDE-85/MeTHPA epoxy resin modified by polyurethane was prepared with polyurethane prepolymer （PUP, formulated by PPG and TDI）, chain-extended reagent（1,4-BDO） and crosslink agent （TMP）. The curing reaction mechanism and kinetics characters of the modified resin were discussed by DSC and infrared spectrum analysis. The investigation on curing reaction mechanism indicates that polymer network Ⅰ was obtained by the curing reaction between TDE-85 and MeTHPA, and polymer network Ⅱ was obtained by the chain-extended and crosslinking reaction of 1,4-BDO, TMP, and PUP, meanwhile, the graft chemical bond is formed between polymer network Ⅰ and polymer network Ⅱ. The investigation on kinetics shows that the apparent activation energy of curing reaction decreased obviously with PU addition, and the activation energy of the resin dropped from 83, 14 kJ/mol to 67.91 kJ/mol with PU modification.