酶解木质素染料分散剂的构建及其作用机理解析

Enzymatic hydrolysis lignin from biorefinery industry is prolific and and renewable, but has poor chemical reactivity. Lignin based dye dispersants have the characteristics of good high temperature stability, nontoxicity, but have destitute dispersibility due to its low sulfonation efficiency. However, the phenolic hydroxyl groups of lignin are oxidized to quinone structure lightly, which cause the deep color of lignin, so result in fiber stain and dye reduction efficiently when lignin was used as dye dispersant. More importantly, the inconclusive mechanisms of action of sulfonated lignin dispersant application on disperse dye and the interactions with fiber have seriously hindered the application of biorefinery lignin in areas such as dye dispersant and composite functional materials. In this project, a new dye dispersant is synthesized based on enzymatic hydrolysis lignin to resolve the key technical issues of low sulfonate degree, fiber stain and dye reduction by high-efficiency grafted sulfonation on phenolic hydroxyl, and then etherification with epichlorohydrin to block the rest phenolic hydroxyl crosslink lignin molecules. The enzymatic hydrolysis lignin here is pretreated first to enrich phenolic hydroxyl group by enzymolysis and ball milling. The dispersibility performance of modified lignin dispersant was affected by molecular weight and functional groups were investigated. The action mechanism such as adsorption characteristics, interaction force of lignin dispersant between dye and fiber will be systematically studied to provide the theoretical basis and technical instruction for optimizing the preparation technology of lignin dispersant and its further application. The lignin-based nano disperse dye was will be prepared with much lower dosage of lignin dispersant by self-assembly to decrease the textile wastewater pollution based on the mechanism of action of lignin dispersant. The implement of this project will open up high-valued applications of methods and technology for enzymatic hydrolysis lignin in areas such as printing and dyeing and composite nano functional materials.

生物炼制中的酶解木质素量大、可再生，但反应活性低，磺化木质素具有优良的高温稳定性，无毒，但磺化效率低,导致分散性能差。高活性的木质素酚羟基，极易转化成深色的醌，而对纤维沾污及对偶氮染料还原。更重要的是木质素分散剂与染料和纤维之间作用机制的不清晰，严重阻碍木质素分散剂在印染及功能复合材料领域的应用。本项目拟通过以酶解、球磨预处理技术增加酶解木质素活性位点，在酚羟基上进行高效的接枝磺化，再通过醚化交联封闭剩余酚羟基、增加木质素分子量制备染料分散剂，解决磺化木质素磺化效率低、分散性差、色深及对偶氮染料还原的关键技术难题；揭示分子量、官能团与分散性能间的规律；阐明木质素分散剂和染料及纤维之间的作用机理，如吸附特征、作用力，为木质素分散剂的优化和应用提供理论基础；并进一步通过自组装制备低分散剂用量的木质素复合纳米分散染料。本项目的实施为酶解木质素在印染及复合纳米材料等领域应用的方法与技术开辟新途径。

生物炼制及制浆造纸中的酶解木质素和碱木质素等量大、可再生，但反应活性低。磺化木质素及木质素磺酸盐具有优良的高温稳定性，且绿色无毒，无公害。但传统酶解木质素及碱木质素磺化效率低，磺甲基化接枝改性技术单一，阻碍其高值化利用。高活性木质素中的酚羟基极易转化成深色的醌，从而对纤维沾污及对偶氮染料还原加重，且木质素分散剂与染料和纤维之间作用机制的不清晰，严重阻碍木质素分散剂在印染及功能复合材料领域的应用。本项目研究成果如下：1、木质素活化、接枝磺化等工艺及封闭酚羟基制备了羟丙基磺化缩合木质素两亲聚合物，并通过核磁等手段进行了结构表征；2、羟丙基磺化缩合木质素改性两亲聚合物作为染料分散剂，具有显著的分散性能和较低的还原性能；3、重点探索了木质素分散剂和分散染料吸附特征及其相互作用机制；4、利用木质素染料分散剂制备木质素复合纳米分散染料及性能研究；5、木质素交联接枝改性制备水凝胶吸附染料及等其他拓展改性利用研究。本项目的实施为木质素在印染及复合纳米材料、高值改性利用等领域奠定应用基础。