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利用酚化方法对木质素进行修饰,使其接入活性基团,考察了不同的酚单体对木质素改性效果的影响,优化了漆酶催化改性碱木质素和对甲苯酚的共聚反应过程,并对共聚产物进行了表征和性能测试。研究表明,邻苯二酚改性后的碱木质素的酚羟基质量摩尔浓度增加最显著,由6.95 mmol/g提高到10.83 mmol/g,提高了55.83%。共聚反应的最佳反应条件为:反应体系的最适质量分数为80%丙酮溶液,反应温度为30℃,pH 3.5,最适碱木质素与对甲酚质量比为0.5/1,最佳酶浓度为300 U/m L,反应时间为16 h。在最适条件下,共聚物产率显著提高,可达93.6%。邻苯二酚改性后的碱木质素和对甲酚聚合后的产物分子质量明显增加,由2 770 g/mol提高到20 481 g/mol,增加了约10倍,热稳定分析表明聚合产物的热学稳定性比改性前有所提高。
Phenol was used to modify the lignin to access the active groups. The effects of different phenolic monomers on the modification of lignin were investigated. The laccase-catalyzed copolymerization of alkali lignin and p-cresol was optimized Reaction process, and the copolymer was characterized and tested. The results showed that the mass concentration of phenolic hydroxyl group of alkali lignin modified by catechol increased the most from 6.95 mmol / g to 10.83 mmol / g, increased by 55.83%. The optimal reaction conditions were as follows: the optimum concentration of the reaction system was 80% acetone solution, the reaction temperature was 30 ℃, pH 3.5, the optimum alkali lignin and p-cresol weight ratio was 0.5 / 1, the best enzyme The concentration of 300 U / m L, the reaction time was 16 h. Under optimum conditions, the yield of copolymer increased significantly, up to 93.6%. The molecular mass of catechol-modified alkali lignin and p-cresol polymerized products increased significantly from 2 770 g / mol to 20 481 g / mol, an increase of about 10-fold. Thermal stability analysis showed that the polymerization products The thermal stability of the modified than before improved.