酚化酶解木质素-环氧树脂/环氧树脂复合材料的合成及性能

以酶解木质素(EHL)为原料,采用苯酚-硫酸法对其进行酚化改性,所得酚化木质素(PL)在碱性条件下,与环氧氯丙烷(ECH)合成木质素-环氧树脂(L-EP),利用FT-IR对产物进行表征。探讨单因素反应条件对酚化工艺的影响。结果表明:反应时间3.0h、反应温度95℃、2mol/L H_2SO_4用量为4mL/g时,木质素的酚化效果最佳,其酚羟基含量达到4.632mmol/g,较EHL提高42%。研究了不同L-EP添加量对L-EP/环氧E-51复合材料力学性能和热性能的影响。结果显示:L-EP的添加量为5%时,L-EP/环氧E-51复合材料的拉伸强度最好,较纯E-51提高26%;随着L-EP添加量的增加,L-EP/环氧E-51复合材料的热稳定性增强。采用非等温法分析环氧E-51和L-EP/环氧E-51复合材料的固化动力学,结果证明:L-EP对复合材料固化有一定的促进作用。

Synthesis and properties of phenolic modified enzymatic hydrolysis lignin-epoxy resin/epoxy resin composites

With the enzymatic hydrolysis lignin (EHL)as the raw materials,and the phenol-sulfuric acid method was used to modify EHL.Under alkaline conditions,the lignin-epoxy resin (L-EP)was synthesized by phenolated lignin (PL)reacted with epichlorohydrin (ECH).The structure of EHL and its modification and the synthetic resin were analyzed by FT-IR.The effects of single factor reaction conditions on the process of phenolation were dis-cussed.The results indicate that the effect of modification is the best under the condition of 3.0 h,95℃ and 4 mL/g H 2 SO4 (2 mol/L),and the content of phenolic hydroxyl group reaches 4.632 mmol/g,which increases by 42%compared with EHL.The effects of different L-EP adding amount on the mechanical properties and thermal proper-ties of L-EP/epoxy E-51 composites were investigated.The results show that the tensile strength of L-EP/epoxy E-51 composites is the best when the amount of L-EP is 5%,which increases by 26% compared with that of the pure E-51 epoxy resin.With the increase in the amount of L-EP,the thermal stability of L-EP/E-51 composites is en-hanced.The non-isothermal method was used to analyze the curing kinetics of epoxy E-51 and L-EP/E-51 compos-ites.The results reveal that L-EP has a certain effect on the curing of L-EP/epoxy resin composites.