【作者】 向育君；

【导师】 徐伟箭；

【作者基本信息】 湖南大学 ， 化学工程与技术， 2013， 博士

【摘要】 木质素磺酸盐是造纸工业最主要的副产物之一，仅我国每年就有数百万吨木质素磺酸盐产生，目前只有很少的一部分得到利用，因此，积极开发木质素磺酸盐产品，不断拓宽其应用范围，既有利于环保，也有利于资源的利用。高分子水凝胶是一类能在水中溶胀，但又不溶于水，具有三维网状分子结构的功能材料，高分子水凝胶在农业、建筑业、医药行业、生物技术等方面都有重要的应用。高分子水凝胶按来源分为合成高分子水凝胶和天然高分子水凝胶，制造合成高分子水凝胶的原料主要来源于石油工业，是不可再生资源，且这类水凝胶的生物可降解性大多较差，在资源匮乏，环境保护迫在眉睫的今天，天然高分子水凝胶的研发工作具有长远战略意义。木质素磺酸盐具有三维网状结构，分子中富含羟基、羧基、磺酸基等亲水基团，理论上是一种较好的制备水凝胶的原材料。本论文着眼于木质素磺酸盐的开发利用，从制造木质素磺酸盐水凝胶入手，对木质素磺酸盐中还原糖的去除，以及木质素磺酸盐水凝胶的制备进行了研究，开发出一种能有效降低木质素磺酸盐中还原糖的方法，并成功制备出一种无需外加交联剂的、溶胀性好的改性木质素磺酸钠水凝胶并利用所制备的改性木质素磺酸钠水凝胶制备了银/改性木质素磺酸钠水凝胶纳米复合材料，此外，还将改性木质素磺酸钠水凝胶应用于药物缓释，研究了改性木质素磺酸钠水凝胶对阿魏酸哌嗪的缓释作用。研究表明通过酸水解-盐析法能有效降低市售的木质素磺酸盐中的还原糖。这种方法的最优操作条件为：所用木质素磺酸钠的质量为溶液质量的2%，所加硫酸的质量为总质量的11.78%，80oC下水解4小时，盐析时加入质量为总质量20%的氯化钠。以经过降糖处理的木质素磺酸钠为原料，通过氧化、磺化改性后制得改性木质素磺酸钠。改性木质素磺酸钠分子中的酚羟基、羧基、磺酸基的含量分别提高了29%、3.4%、9.7%。改性木质素磺酸钠经过酸性条件下的热处理后，再用氢氧化钠溶液处理，抽滤后收集固体，并用去离子水洗涤至中性即制得改性木质素磺酸钠水凝胶。通过对影响改性木质素磺酸钠水凝胶水溶胀性和得率的主要因素进行单因素实验，确定了制备改性木质素磺酸钠水凝胶的优化制备路线即:8克经过酸水解-盐析纯化的木质素磺酸钠，溶于200mL去离子水，加入6毫升浓度为30%的H2O2，氧化温度50℃，氧化时间为40分钟，加入2.5克亚硫酸钠，磺化时间80分钟，烘干温度135℃，烘干时间90分钟，NaOH溶液浓度0.3M，碱处理时间40分钟，碱处理温度为室温25度。通过这种方法制备的改性木质素磺酸钠水凝胶的水溶胀性为30.2克/克干水凝胶，得率为10%左右。通过对制得的的湿水凝胶进行超声分散、扫描电镜观测、超声分散液干燥物的水溶性实验，以及超声分散液的动态光散射实验，证实了所制备的改性木质素磺酸钠水凝胶是由其微凝胶通过物理交联而成。微凝胶是微观尺寸的水凝胶，是一种制备无机纳米材料的优良模板或微反应器，作者将改性木质素磺酸钠水凝胶经过超声分散后制得了改性木质素磺酸钠微凝胶，然后利用微凝胶分子网络的限域作用，通过原位还原法制备了平均粒径为9.6nm的纳米银粒子，将这种纳米银-微凝胶分散液干燥后制得了含纳米银的改性木质素磺酸钠干凝胶。这种复合材料有望在医药和催化等领域得到应用。木质素磺酸钠无毒，具有生物相容性，由其制备的改性木质素磺酸钠水凝胶具有较好的水溶胀性，因此具有成为药物缓释材料的潜力，实验证实了改性木质素磺酸钠水凝胶对阿魏酸哌嗪具有一定的缓释能力，并且这种水凝胶在酸性条件下的溶胀性急剧下降，因此可用来作为一些对胃有刺激药物的缓释载体。总之，作者制备的改性木质素磺酸钠水凝胶是一种新型的，没有外加交联剂的天然高分子水凝胶，它是由其微凝胶物理交联而成，通过超声分散可转变为微凝胶，这种水凝胶因其独特的性质有望在纳米材料制备、药物缓释、重金属离子吸附、生化分离等领域得到应用。更多还原

【Abstract】 Lignosulfonate is one of by-products in paper manufacturing, just in china, thereare millions tons of lignosulfonate are produced each year, but only a very smallamount of them are utilized. Therefore, efforts to develop the lignosulfonate productsand broaden its use are beneficial not only to environmental protection but also toeffective application of resources. Polymeric hydrogel is a type of three-dimensionalnetwork like functional material which is swollen in water but insoluble in water,polymeric hydrogels have important applications in agriculture, construction,pharmaceutical industry, biotechnology, etc. the origin of polymeric hydrogel can beclassified into synthetic polymeric hydrogel and natural polymeric hydrogel, the rawmaterial for the manufacture of synthetic polymer hydrogel mainly come from the oilindustry, is a non-renewable resource with low biodegradability. On the context of thelack of resource and strong sense of environmental protection, the researches on thedevelopment of natural polymeric hydrogel have a long-term strategic significance.Lignosulfonate have a tri-dimensional network like structure containing hydroxyl,carboxyl and sulphonyl groups in their molecules, these structural featurestherotically ensured them to be a good raw material for preparing the hydrogel. Thispaper focuses on the development and utilization of lignosulfonate. Firstly, we studiedthe preparation of lignosulfonate hydrogel, made an investigation into the removal ofreducing sugar in lignosulfonate and preparation of modified lignosulfonatehydrogel.Through this study, we found an effective method to reduce the reducingsugar in lignosulfonate and successfully prepared a type of modified lignosulfonatehydrogel with good water swollen capacity under conditions of no addition ofcross-linking agent. Furthermore, the corresponding studies on the application of thismodified lignosulfonate hydrogel in preparation of nano-material and drug deliverywere also conducted.The research results indicate that the reducing sugar in commercially availablelignosulfonate can be effectively reduced through acid-aided hydrolysis-salting outmethod. The optimal operating conditions are addition of2wt%of sodiumlignosulphate and11.78wt%of sulphonic acid chloride of total solution weight,4hof hydrolysis time at80oC and addition of20wt%of sodium of total weight duringsalting out process. The modified sodium lignosulfonate is prepared by using sodium lignosulfonate after removal of reducing sugar as starting material through oxidationand sulphuration modification procedures. The content of phenol group, carboxylgroup and sulphonyl group in modified sodium lignosulphate is promoted by29%,3.4%and9.7%, respectively. The modified sodium lignosulfonate was thermallytreated under acidic conditions followed by treatment in sodium hydroxide solution;the collected solid by filtration under reduced pressure is modified lignosulfonatehydrogel. The single factor experiment was conducted by varying the level of themajor impact fators that affecting the water swollen capacity and yield of modifiedsodium lignosulfonate, and the optimal preparation route was determined, that is:8gof purified sodium lignosulphate by hydrolysis-salting out method,200mL ofdeionized water and6mL of30%H2O2was mixed, the mixture was heated to50oC,then2.5g of sodium sulfite was added to the mixture and the solution wassulphonated for80min. The solution after sulphonation was dried at135oC for90min, and then the solid was hydrolyzed in0.3M sodium hydroxide for40min at roomtemperature, the yield is about10%based on sodium lignosulfonate. The obtainedmodified sodium lignosulfonate has a water swollen capacity of30.2g/g xerogel.A serial of experiments around the obtained wet hydrogel includes ultrasonicdispersion, scan electron microscope observation; water solubility of dried solid afterultrasonic dispersion and dynamic light scattering, the experiment resultsdemonstrated that the obtained modified sodium lignosulfonate hydrogel is formed byphysical cross-linking. Microgel comprises of particles of micrometer size, it is anexcellent template or micro-reactor for the synthesis of inorganic nano-materials. Weprepared modified sodium lignosulfonate microgel by ultrasonic dispersion, and thenprepared nano silver particles with avarage particle size of9.6nm by reduction in-situbased on the confinement effect of microgel network structure. The dryness of themicrogel-nano silver dispersion leads to nano silver/modified sodium lignosulfonatecomposite microgel. This composite material is expected to be applied in the fields ofmedicine and catalysis. Sodium lignosulfonate is non-toxic and biocompatible, andthe modified sodium lignosulfonate prepared from it has better water swollen capacity,this feature endowed it potential as drug delivery material. The experiment confirmedthat modified sodium lignosulfonate has sustained release property to piperazineferulate. Since the water swollen capacity of this hydrogel can undergo a sharpdeclining under acidic environment, it can be used as sustained release carrier ofdrugs that has stimulation on stomach. In general, modified sodium lignosulfonatehydrogel is a novel type of natural polymeric hydrogel without any addition of cross –linking agent and formed by physical cross-linking of microgel particles. It can bedispersed into microgel by ultrasonic dispersion. Because of its unique properties, thishydrogel is expected to be applied in the fields of nano-material preparation, drugdelivery, and heavy metal ion adsorption and biochemical separation.更多还原