单宁-糠醇树脂胶黏剂基元反应竞争机制及其结构调控研究

As a biomass resource, the utilization of tannin is rather limited. The tannin-based enterprises are hard to survive. To utilize tannin, the structure characteristics of wattle and bayberry tannin will be studied. Some model compounds based on the tannin structure will be used to react with raw materials or oligomers of furfuralcohol to study their reaction mechanism. By the calculation based on the theory of quantum chemistry, some informations on the reaction conditions and its happening between them, the micro reaction process, performances of the reaction products and the competition between reactive groups will be given. .By the analysis of the chemical structure of the reaction products, the formation of their structure will be studied. Therefore, the key scientific problem on the competition reaction in the tannin/ furfuralcohol reaction system and the reaction mechanism with tannin-furfuralcohol resin will be explored. The study will be a guide on the preparation of tannin-furfuralcohol resin. By the optimization of the preparation procedures, the tannin-furfuralcohol resin could be used on wood constructions. .In tannin-based adhesives, formaldehyde is normally used as a crosslinker. However, all of the materials for the preparation of tannin-furfuralcohol are environment-friendly. Therefore, the objective of this work is to breakthrough the bottleneck of the past studies on the utilization of tannin especially in the field of wood industry and then to be useful for the application of tannin.

单宁是一类重要的生物质资源，但用途单一，资源利用率不高。本研究依托我国单宁资源优势，以我国工业化单宁原料为研究对象，在研究单宁基本结构特征基础上，选取单宁分子模型化合物，利用量子化学理论计算，提供单宁分子与糠醇分子及其低聚物之间的反应条件、微观反应历程、产物性质、反应竞争性等信息；利用化学结构分析方法，明确改性产物结构特征，揭示产物结构形成过程；综合两种分析方法结果，重点突破单宁-糠醇树脂基元反应竞争机制关键科学问题，解析单宁-糠醇树脂反应机理，指导树脂分子结构调控和分子设计，通过合成工艺优化，实现室外级木结构建筑用单宁-糠醇树脂胶黏剂的定向制备。较之常规单宁基胶黏剂，单宁-糠醇树脂胶黏剂更具天然环保性优势。通过本项目的实施，进一步完善单宁-糠醇树脂合成基础理论，并为单宁基胶黏剂的实际应用提供新思路。

单宁是一类重要的生物质资源，用于木材胶黏剂时，普遍存在胶接强度不高、耐水性差等问题。为此，本项目从单宁原料预处理和交联固化剂的选择两方面着手，分别开展了单宁-羟甲基化糠醇、羟甲基化单宁-糠醇、单宁-酚醛树脂、羟甲基化单宁-酚醛树脂、单宁-乙二醛、单宁-己二胺等树脂胶黏剂反应机理与性能研究，提出了以单宁为原料制备耐水型胶黏剂的可行途径。通过对间苯二酚-羟甲基糠醛、羟甲基酚-糠醇等模型化合物反应产物及树脂胶黏剂化学结构分析，明确了改性产物结构特征，探讨了单宁与糠醇之间的共缩聚与自缩聚竞争反应机制，研究了单宁-糠醇树脂及单宁改性树脂反应机理。研究了反应条件对单宁基胶黏剂性能的影响，优化了单宁胶黏剂改性方法。研究结果表明，高耐水性单宁-糠醇树脂胶黏剂的制备可通过单宁羟甲基化或糠醇羟甲基化实现，原料的羟甲基化程度直接影响树脂性能，缩聚反应宜在弱酸性条件下进行。在酚醛树脂中，预处理单宁可替代10%及以上酚醛树脂用于人造板制备。乙二醛改性单宁可有效改善脲醛树脂的耐水性，以己二胺作为交联剂可制备具有交联网络结构的单宁基胶黏剂，其具有良好的耐水性。本项目研究结果为解决单宁基胶黏剂及其改性树脂如脲醛树脂和酚醛树脂的力学强度性能和耐水性问题提供了新思路，将有利于生物质原料单宁在木材胶黏剂中的实际应用。