木质素基两性聚电解质的制备与表征

Preparation and Characterization of a Lignin-based Amphoteric Poly-electrolyte

以木质素三甲基季铵盐（QL）和海藻酸钠（SA）为原料,以戊二醛为交联剂,制备木质素三甲基季铵盐-海藻酸钠两性聚电解质（QL-SA）.以含氮量和对酸性黑ATT的絮凝性能作为指标,通过单因素试验得出最佳合成条件为：交联剂用量为4％（占反应体系的质量分数）,反应温度为70℃,QL与SA质量比为2∶1,交联时间为4h,最优条件下测得对酸性黑ATT的脱色率为90.08％.考察了其溶解性以及两性聚合物的特点——等电点,采用FI-IR表征了产物的结构,利用TG和DSC对其热稳定性进行表征.结果表明：QL和SA接枝成功,其含氮量由QL的4.21％减少为3.69％,且反应后的QL-SA热稳定性较两个原料好.QL-SA的等电点为5.76,等电点范围为4～10,具有两性化合物的特征.

In order to improve the molecular weight and application of lignin, trimethyl quaternary ammonium salt of lignin-sodium alginate polyampholyte （QL-SA） was prepared with trimethyl quaternary ammonium salt of lignin （QL） and sodium alginate （SA） by crosslinking, and glutaraldehyde was selected as the cross linker in present study. Based on the nitrogen content and flocculate ability on the acid black ATT, the reaction conditions were optimized. The QL-SA with high quality could be obtained as the QL and SA with mass ratio 2 ： 1 were crosslinked by 4% glutaraldehyde at 70 ℃ for 4 h. For the QL-SA obtained under this optimum condition, the decolorization rate of acid black ATY was 90. 08 %. The solubility and amphoteric polymer characteristics, ie, isoelectric point, was also investigated. Its structure was analyzed by FT - IR, TG and DSC. The results revealed that QL and SA were grafted successfully, the nitrogen content reduced from 4.21% to 3.69 %, and the thermal stability of QL-SA was superior tO that of QL and SA. Its isoelectric point was 5.76, and ranged from 4 to 10. The QL-SA was an amphoterie compound.