以木质素磺酸钠(SL)为原料,通过亲电取代反应将聚乙二醇(PEG600)接枝到SL分子中制得木质素磺酸钠聚氧乙烯醚(SL-PEG).对SL-PEG进行结构表征,发现SL-PEG分子中含有较多的聚氧乙烯醚结构单元,重均分子量最大达到32900;接枝反应主要发生在SL的酚羟基上,其酚羟基含量由1.17 mmol·g^-1下降至最小0.30 mmol·g^-1.将SL-PEG与十六烷基三甲基溴化铵(CTAB)通过静电自组装方法制备木质素基阴-阳离子表面活性剂CA-SL.分别研究CA-SL的表面活性和溶液行为,发现CA-SL可使水溶液的表面张力降低至38.75 m N·m^-1,其在水溶液中的临界聚集浓度可达0.0050~0.0065 g·L^-1,远低于SL.将CA-SL作为分散剂制备吡虫啉和烯酰吗啉水悬浮剂,考察其分散稳定性能.结果表明,CA-SL具有良好的砂磨及分散效果,在热贮过程中能有效遏制2种悬浮剂的膏化和颗粒粗化现象,悬浮剂的稳定性良好.
The sodium lignosulphonate polyethenoxy ether (SL-PEG) was prepared by electrophilic substitution reaction using sodium lignosulphonate (SL) and polyethylene glycol (PEG600). The chemical structure of SL-PEG was characterized and the weight-average molecular weight of SL-PEG was up to 32900, because of the grafting of many polyethenoxy ether units. The grafting reaction was found to occur at phenolic hydroxy of SL, thus the phenolic hydroxy contents of SL-PEG reduced from 1.17 to 0. 30 mmol · g^-1 Subsequently, the lignin-based cationic-anionic surfactant (CA-SL) was prepared via electrostatic self- assembled method combining SL-PEG with cetyl trimethyl ammonium bromide ( CTAB). The surface activity and aqueous solution behaviour of CA-SL was studied, the result showed that the CA-SL aqueous solution presents far lower surface tension (minimum to 38.75 mN·m^-1) and critical aggregation concentration (0. 0050 - 0.0065 g· L^- 1 ) than SL. In order to investigate the dispersing and stabilizing properties of CA-SL, the CA-SL was used as dispersants to prepare imidacloprid and dimethomorph suspension concentrates. The results indicated that the CA-SL has good grinding and dispersion effect, and these two suspension concentrates exhibit good stability during the heat storage process, owing to its excellent ability to restrain the creaming and particle coarsening effectively.