受阻胺类固化剂固化环氧树脂的固化过程研究

Study on Curing Process of Epoxy Resin Cured with Hindered Amine Curing Agent

通过差示扫描量热法(DSC)研究了几种不同基团取代脂肪族二元胺中的一个氢原子所形成的三官能度脂肪胺类固化剂固化环氧树脂的过程。分别使用Kissinger模型和Flynn-Wall-Ozawa模型对三种固化剂固化环氧树脂的动力学参数进行了计算。结果表明,三种固化剂固化环氧树脂的反应活性大小比较为:N-乙基乙二胺≈N-甲基乙二胺>N-苯基乙二胺。这不仅与得到的固化度-时间曲线结果相符,并且可以从结构的角度以电子效应,共轭效应和位阻效应理论给予合理解释。N-苯基乙二胺中,由于苯环的刚性较大,空间位阻效应尤为明显,活化能(E a)在固化度(α)=0.5时为61.99 kJ/mol,而在α=0.9时达到97.63 kJ/mol,随着固化度的增加反应活性迅速下降,因此该类固化剂固化过程中更需要控制工艺。

The curing process of epoxy resin by tri-functional aliphatic amine curing agent formed by several different functional groups replacing one H atom in aliphatic binary amine was studied based on differential scanning calorimetry(DSC)test.Curing kinetic parameters of three curing systems were calculated by measures of Kissinger model and Flynn-Wall-Ozawa model.The results show that the reactivity of three curing agents is N-Ethyl ethylenediamine≈N-Methyl ethylenediamine>N-phenylethylenediamine,which is consistent with the curable degree-time curve,and it can be explained by the theory of electronic effect,conjugate effect and steric hindrance effect.The rigid benzene of N-phenylethylenediamine leads to steric hindrance effect noticeably.When the degree of cure(α)is 0.5,the activation energy(E a)could achieve 61.99 kJ/mol,and whenαis 0.9,E a could reach 97.63 kJ/mol.With the increase of curing degree,the reactivity decreases rapidly,therefore,it is necessary to control the curing process.