多功能甲壳素基高吸水树脂的均相合成及其性能

Chitin is the second most abundant biopolymer (after cellulose) and is the only natural basic polysaccharide widely found on the earth. However, it is perhaps the least exploited biomass source to date. The previous researches using chitin as a raw material for graft copolymerization was restricted, and most of them caught out under heterogeneous conditions. Therefore, the research of graft copolymerization under homogeneous condition is significance affluent in the theoretical of chitin research. The freezing-thawing cyclic (FTC) process was applied to dissolve chitin. A transparent homogeneous alkaline solution was obtained. It was utilized directly for preparing a multifunctional chitin-based acrylate superabsorbent polymers (SAPs) by graft copolymerization under static solution conditions without nitrogen protection. The NaOH was used as a solvent to dissolve chitin, and also used as the reagent to neutralize the acrylic acid. No excess solvent emissions after the synthesis reaction, which is conducive to realize the green synthesis of superabsorbent polymers. The structures were characterized by the means, including nuclear magnetic resonance (NMR) and infrared spectroscopy (IR). The dynamic IR, ultraviolet spectroscopy (Uv), multi-parameter chemiluminescence system and electron spin resonance (ESR) were applied to investigate the formation of chitin macro-radicals and the mechanism of graft copolymerization. It can regulate the synthesize and properties for the materials by changing the content of the free amino groups within the system. Then, the adsorption properties for the materials on the heavy-metal ions were investigated, as well as the mechanism of adsorption and desorption. Therefore, this project not only can enrich the theory and practice of chemical modification of chitin, can also provide a new way for enhancing the added values of chitin resources. It has important scientific significance and application prospects.

甲壳素是仅次于纤维素的第二大生物质资源，也是唯一大量存在的天然碱性多糖，但其开发利用率极低。对其进行接枝共聚改性的研究有限，且多是在异相条件下进行的，开展均相接枝共聚研究对丰富甲壳素理论研究具有重要意义。拟通过冻融循环处理制备碱甲壳素均相溶液，与丙烯酸接枝共聚制备多功能高吸水材料。NaOH不仅作为甲壳素的溶剂，而且作为中和丙烯酸的反应试剂，反应结束后无多余溶剂排放，有利于实现高吸水树脂的绿色合成。利用核磁共振、红外光谱等对材料结构进行表征。利用动态红外、紫外光谱、多参数化学发光系统、电子自旋共振波谱等研究甲壳素大分子自由基的形成规律和接枝共聚机理。通过对体系自由氨基含量的调整调控材料的合成和性能。并研究该吸水材料对重金属离子的吸附功能以及吸附和解吸附的机理。因此，本项目不仅可以丰富甲壳素化学改性理论和实践，也可为甲壳素资源的高值化提供一条新的途径，具有一定科学意义和应用前景。

随着对资源可持续发展的日益重视，以生物质资源为原料的新材料研究日益受到重视。壳聚糖基高吸水树脂更因其独特的性能，在生理卫生、个人护理等领域更有着潜在的应用价值。直接以甲壳素为原料生产出壳聚糖基高吸水树脂，不仅克服甲壳素脱乙酰生产壳聚糖可能带来的碱污染，而且有利于降低成本。. 本项目主要做了以下几个方面的研究：1）采用浓碱冻融循环处理甲壳素，结合均相脱乙酰，直接制备了甲壳素/壳聚糖基高吸水树脂。研究了各种合成条件、甲壳素的脱乙酰度和分子量等对树脂吸水性能的影响。利用现代结构分析手段，初步探明了高吸水树脂的结构，以及均相条件下过硫酸盐引发的甲壳素接枝聚丙烯酸的可能反应机理。尽管，与壳聚糖接枝聚丙烯酸的机理类同，均是发生在氨基葡萄糖单元的C2-NH2上。但提出了一条由甲壳素生产壳聚糖基高吸水树脂的清洁生产工艺，有一定的潜在应用前景。同时，探讨了微波辅助和无交联剂条件下的壳聚糖基高吸水树脂的合成工艺，初步进行了树脂对金属离子和染料的吸附作用研究，对壳聚糖基高吸水树脂的绿色合成及应用有一定借鉴意义。2）分别以玉米、野豌豆、荔枝核、橡子淀粉和水稻、小麦秸秆等生物质材料为原料，成功开发出一系列绿色高吸水树脂。3）以再生甲壳素及高吸水树脂为原料，开发了水包油型乳化剂、负载Cu2O的光降解催化剂及改性吸附剂等材料。4）初步开展了生物质基复合材料的研究工作，合成了尼龙/秸秆纤维和PBS/纤维等可降解塑料。5）尝试建立了针对农药草甘膦的单分子荧光分析方法。. 本研究着眼于甲壳素、淀粉、秸秆纤维等生物质资源，尝试构建以生物质原料为基础的高吸水树脂或复合塑料，对扩大可降解材料的原料来源，以及提高生物质资源的附加值均有较好的借鉴意义。