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采用红外光谱和非等温DSC法研究了羧甲基纤维素(CMC)/E44环氧树脂/4,4′-二氨基二苯基甲烷(DDM)体系的固化过程和动力学。红外光谱研究表明,CMC可促使E44/DDM体系在固化过程中生成更多的聚醚结构。DSC非等温固化反应动力学研究表明,CMC的加入在反应初始阶段降低了E44/DDM体系的反应活化能,促进固化反应的进行。采用等转化率法和自催化模型对固化反应的过程进行研究,建立动力学方程。由Starink等转化率法获得E44/DDM和CMC/E44/DDM体系的活化能随转化率的变化情况。E44/DDM体系的活化能随转化率升高而显著降低;CMC/E44/DDM体系的活化能随转化率升高变化不明显,在相同含量时,相对分子质量高的CMC体系活化能高。采用SB自催化模型研究E44/DDM和CMC/E44/DDM体系的固化过程并获得模型参数。对CMC/E44/DDM体系,SB模型对实验结果拟合较好;对E44/DDM体系,SB模型和实验结果吻合效果较差。由于E44/DDM体系活化能随固化度有显著变化,因此采用改进的变活化能自催化模型描述其实验现象,结果显示该法获得的模型能够较好地描述实验现象。动力学模型的建立能够为工艺参数的选择和工艺窗口优化提供理论依据。
The curing process and kinetics of carboxymethyl cellulose (CMC) / E44 epoxy resin / 4,4’-diaminodiphenylmethane (DDM) system were studied by infrared spectroscopy and non-isothermal DSC. Infrared spectroscopy studies show that CMC can promote the E44 / DDM system to generate more polyether structure during curing. DSC kinetics of non-isothermal curing reaction showed that the addition of CMC in the initial stage of the reaction reduces the E44 / DDM reaction activation energy, and promote the curing reaction. The conversion process and autocatalytic model were used to study the process of curing reaction, and the kinetic equation was established. By Starink conversion rate obtained E44 / DDM and CMC / E44 / DDM system activation energy with the conversion rate changes. The activation energy of E44 / DDM system decreased significantly with the increase of conversion rate. The activation energy of CMC / E44 / DDM system did not change obviously with the increase of conversion rate. At the same content, the activation energy of CMC system with high molecular weight was high. The SB autocatalytic model was used to study the curing process of E44 / DDM and CMC / E44 / DDM systems and the model parameters were obtained. For the CMC / E44 / DDM system, the SB model fits well to the experimental results; for the E44 / DDM system, the SB model is not consistent with the experimental results. Since the activation energy of E44 / DDM system changes significantly with the curing degree, an improved self-catalytic model with variable activation energy is used to describe the experimental phenomena. The results show that the model obtained by this method can describe the experimental phenomena well. The establishment of dynamic model can provide a theoretical basis for the selection of process parameters and optimization of the process window.