三羟基苯甲基氨基均三嗪与双酚A型环氧树脂的固化反应研究

Study on the curing behavior of 2,4,6-tri(hydroxylphenylamine)-s-triazine and diglycidyl ether of bisphenol A

采用等转化率法研究了2,4,6-三(羟基苯甲基氨基)-均三嗪(MFP)与双酚A型环氧树脂(DGEBA)在等温和非等温条件下的固化反应行为,两种条件下MFP/DGEBA固化反应的表观活化能(Eα)均随转化率(α)增加呈先减后增的趋势(α=0.25时取得最小值).由于仲胺基和酚羟基对环氧基反应的不等活性,非等温固化反应时两种反应先后发生,形成Triazine-NCH2-CH(OH)-结构后,再形成ArO-CH2-CH(OH)-结构并产生交联,前后两阶段Eα分别为69.88、6.8 kJ.mol-1.对等温固化反应,由于起始反应温度高,仲胺基和酚羟基几乎同步与环氧基发生反应,两者的相互催化作用使反应前期Eα相对较低(59.1 kJ.mol-1),固化反应速度较快,引起体系粘度迅速增大,扩散控制反应提前,从而造成反应后期Eα(89.7 kJ.mol-1)相对较大.

The curing behavior of 2, 4, 6-tri （hydroxylphenylmethylmino）-s-triazine （MFP） and diglycidyl ether of bisphenol A （DGEBA） was investigated intensively by DSC via isoconversional method. An obvious non-linear relationship of the apparent activation energy （Eα） vs. conversion （α） was found for isothermal and non-isothermal curing process. Eα of both curing process reached to a minimum value when α = 0. 25. For non-isothermal curing process, the occurrence of reaction of triazine-NH with oxirane ring was prior to the reaction of Ar-OH with oxirane ring due to the unequal activity of them, so the structure of Triazine-NCH2-CH （OH）- was formed before the formation of ArO-CH2-CH （OH）-, and the average Eα was 69.8 kJ·mol^-1 when α〈0.25, and 86.8 kJ·mol^-1 when α〉0.25. The formation of local ordered structure during the non-isothermal curing process might be responsible for the relationship of Eα vs. α. For isothermal curing reaction process, three-dimensional chain extension occurred at the beginning of reaction for high curing temperatures. An intermolecular associated catalytic effect of Triazine-NH and Ar-OH on their reactivity towards oxirane group was the main reason for low Eα value in the beginning stage of isothermal curing process. The average Eα was 59.1 kJ·mol^-1 when α〈0.25, and 89.7 kJ·mol^-1 when α〉0.25.