不同分子量木质素磺酸钠染料分散剂的结构及性能

Structure and performance of dye dispersant sodium lignosulfonate with different molecular weight

采用超滤方法对木质素磺酸钠进行分离得到3种不同分子量级份。采用凝胶渗透色谱、紫外光谱、电位滴定等方法研究各级份的结构特征及其对分散染料性能的影响。结果表明,随着分子量的增加,木质素磺酸钠颜色加深、纯度提高,分子结构中愈创木基含量增多,酚羟基、磺酸基和羧基的含量降低;高分子量木质素磺酸钠对分散染料具有更优的分散性和高温稳定性,染料上染率也随其分子量的增大而增加,且当木质素磺酸钠浓度较高时,分子量增大,对纤维沾污减弱。木质素磺酸钠对染料的还原破坏作用与分子量和酚羟基含量有关,采用截留分子量大于2.5×103的膜提纯的木质素磺酸钠级份对染料还原性最低,还原水解率由未提纯时的26.0%降为6.9%,且该级份木质素磺酸钠具有最优的匀染性能。

Three purified sodium lignosulfonate （SL） samples with various molecular weights were prepared by fractionation using ultrafiltration.The structural characteristics of SL samples and its effect on performance of dye are investigated by means of gel permeation chromatography, ultraviolet spectrophotometry, electrolytic titration and high temperature dying process. The results show that, with increase of molecular weight, the color of SL becomes darker, its purity increases, and the content of guaiacyl increases while phenolic hydroxyl, carboxyl and sulfonic decrease. The SL with high molecular weight is of good dispersibility and high temperature stability for dispersing dyestuff, and the dyeing rate of dyestuff increases also with increase of SL molecular weight. The staining of SL for fiber could be weakened when its molecular weight is larger and its concentration is higher. In addition, the reduction destruction of SL for dyestuff depends on molecular weights and the content of phenolic hydrophilic group. The SL fraction with molecular weight above 2.5×10^3 can make dyestuff the most excellent levelling property and the lowest reduction effect, the reduction and hydrolysis rate reduce from 26.0% of unpurified SL to 6.9%.