废纸纤维环氧化改性及其反应动力学研究

Study on epoxidation of second fiber and its reaction kinetics

通过废纸纤维环氧基化改性,研究了反应温度和反应时间对改性纤维环氧值和取代度的影响。结果表明,废纸纤维的环氧基取代度随着反应温度的升高和反应时间的延长而增加。红外光谱分析显示改性后废纸纤维中有部分羟基被甲基环氧基团取代,谱图中出现了甲基、亚甲基以及醚键吸收峰的增强变化;X射线衍射分析表明纤维原有的结晶结构受到破坏,相对结晶度明显下降,改性纤维的结晶度为21.04%;TGA分析表明改性后纤维的热稳定性略有下降。确定了废纸纤维环氧基化在不同温度下的反应速率常数分别为k1=0.11(60℃),k2=0.25(70℃)、k3=0.35(80℃)。计算出了环氧基化反应的表观活化能为48.14kJ/mol。

Second fiber was epoxidated by using epichlorohydrin as etherifying agent.Effects of reaction time and reaction temperature on degree of substitution and epoxy value of the modified fiber were studied.It was indicated that they increases with prolonging of reaction time or increment of reaction temperature under 70℃.The characteristic absorption peaks of epoxidated fibers were observed from IR spectrum,which showed a lot of hydroxyls on the fiber surface were replaced by the methyl epoxy group of epichlorohydrin.The calculations based on XRD photo showed the crystallinity was reduced to 21.40%with the increased gap between molecular chains of modified fiber.TGA analysis indicated that thermal stability of fibers decreased slightly after modification.It was concluded in this paper that the rate constant of epoxidation of second fiber was ordered by 0.11,0.25,0.35 under reaction temperature of 60,70 and 80℃,respectively.Activation energy of fiber epoxidation was 48.14kJ/mol.