木质素热塑性酚醛塑料的固相缩聚研究

Research on solid-phase condensation of thermoplastic lignin phenol-formaldehyde plastics

木质素储量丰富,是森林资源生物质资源中最丰富的可更新芳香族化合物。木质素的利用是木质素研究领域中一个重要方向。本研究使用木质素为原料制备木质素酚醛树脂,研究了固相缩聚下木质素树脂的物理化学变化,讨论了3种固化温度(1 h、2 h、3 h)对树脂的影响,采用FTIR、TG、DSC等方法对材料性能进行表征。通过探讨不同温度下固相缩聚对树脂性能、热性能、表面形貌等指标影响规律,研究木质素酚醛纤维的固相缩聚行为。结果表明酚醛树脂经过固相缩聚内部材料继续交联反应,反应后树脂残碳率最高达25.3%。适当延长干燥时间有利于酚醛树脂的分子量提高,分子量分布变窄。从而使得聚合物的稳定性和分子链的规则性得到提升。综合分析得出干燥2 h的酚醛树脂具有较优秀的热稳定性,和较高的热固化温度且苯环邻位取代程度高。

Lignin,with abundant reserves,is the most abundant renewable aromatic compound in forest biomass resources.The utilization of lignin is an important direction in the field of lignin research.In this study,lignin was used as a raw material to prepare lignin phenol-formaldehyde resin.The physical and chemical changes of lignin resin under solid-phase condensation were investigated,and the effects of three curing temperatures(1 h,2 h,3 h)on the resin were discussed.The material properties were characterized by FTIR,TG,DSC,and other methods.By exploring the impact of solid-phase condensation at different temperatures on resin properties,thermal properties,and surface morphology,the solid-phase condensation behavior of lignin phenol-formaldehyde fibers was studied.The results showed that the phenol-formaldehyde resin underwent further cross-linking reaction inside the material during solid-phase condensation,and the residual carbon yield of the resin reached a maximum of 25.3%.Properly extending the drying time helped increase the molecular weight and narrow the molecular weight distribution of the phenol-formaldehyde resin,thereby improving the stability of the polymer and the regularity of the molecular chains.Comprehensive analysis indicated that the phenol-formaldehyde resin dried for 2 hours exhibited excellent thermal stability,a high curing temperature,and a high degree of substitution in the phenyl rings.