纤维素基多巴仿生胶黏剂的分子设计、合成与性能研究

Adhesives are widely used in the field of wood processing, biomedicine, electronics, building, mechanics, and food packaging. Because the synthesis and application of commonly used adhesive are harmful to human health and environment, synthesis of novel environmentally friendly adhesives with ideal properties under dry and water conditions has attracted much attention. In this proposal, inspired by the adhesive proteins secreted by marine sessile organisms such as mussels, we aim to explore the cellulose-based catechol-containing adhesives prepared using cellulose, which is the most abundant environmentally friendly materials on Earth. The cellulose macroimitator with various degree of substitution will be prepared by reacting cellulose with 2-bromoisobutyryl bromide. Using atom transfer radical polymerization, various functional monomers with catechol, acylamino, hydroxyl and amino groups will be grafted from cellulose to form cellulose-based adhesives. The adhesive strength of cellulose-based materials in the dry and underwater state will be studied. The influence of chemical structures such as composition, sequence, and concentration on the properties of adhesives will be demonstrated. The unique advantage of cellulose as the stating material to fabricate adhesives will be clarified. Our proposal for cellulose-based adhesives inspired by nature will provide a fundamental and theory insight into the preparation and application of controllable adhesives with ideal properties.

胶黏剂在木材加工、生物医疗、电子、建筑、机械、食品包装等行业有广泛的应用。常用胶黏剂因在生产和使用过程中对人体健康和环境造成危害，研究开发新型环境友好的耐水胶黏剂备受关注。本项目拟采用自然界丰富的环境友好材料──纤维素为基本原料，制备理想胶合性能的纤维素基多巴仿生胶黏剂，对自然界中贻贝等海洋生物所分泌蛋白粘液进行仿生制备和性能研究。纤维素与酰卤试剂反应制得不同取代度的纤维素基大分子引发剂。采用原子转移自由基法，实现含邻苯二酚、酰胺基、羟基、氨基等功能性基团的不同单体在纤维素上接枝聚合。研究胶黏剂在干态和水下的胶合性能，阐明接枝物的基团组成、序列、含量等化学结构对胶合性能的影响机制，探明纤维素作为基底材料制备仿生胶黏剂的独特优势，为纤维素基多巴仿生胶黏剂的制备和应用提供理论基础。

本项目针对常用胶黏剂环境不友好、耐水性差、难以重复使用等问题，以纤维素为原料，将含有邻苯二酚、季铵阳离子、酰胺基团等功能性基团引入到纤维素中，仿生制备了TEMPO氧化纤维素基多巴胶黏剂、接枝共聚纤维素基多巴胶黏剂、多巴阳离子共聚物P(DOPMAm-co-MPTC)胶黏剂、纳米纤维素/没食子酸/聚乙烯吡咯烷酮（CNC/GA/PVP）复合胶黏剂等胶黏剂。通过酰胺化法制备的TEMPO氧化纤维素基多巴胶黏剂绿色环保，有利于细胞附着和增殖，具有优异的生物相容性和高强的胶黏强度。其粘接强度远大于商用纤维蛋白胶（12 kPa）。通过原子转移自由基聚合，将N-（3,4-二羟苯基乙基）甲基丙烯酰胺和甲基丙烯酸甲酯等单体接枝到纤维素基上，合成了一元、二元和多元接枝共聚的纤维素基多巴胶黏剂。接枝共聚的胶黏剂具有良好的耐水性和高强的水下胶黏性能，其对木材、铝片和铁片的水下粘接强度分别为0.25、0.38和0.45MPa，远大于商用“Krazy Glue”以及环氧树脂、聚醋酸乙烯酯和氰基丙烯酸酯等胶黏剂。同时探明了二元接枝的纤维素基多巴胶黏剂在水下胶接时与基板的相互作用机理。将CNC/PVP溶液和GA溶液混合，通过物理氢键交联制备了CNC/GA/PVP复合胶黏剂。CNC/GA/PVP胶黏剂具有优异的可重复使用粘接性能。通过多巴甲基丙烯酰胺单体DOPMAm和阳离子单体MPTC进行自由基共聚反应，制得P(DOPMAm-co-MPTC)多巴阳离子共聚物仿生胶黏剂。将烯丙基纤维素和多巴阳离子共聚物P(DOPMAm-co-MPTC)快速固化，制备了具有优异的湿粘附力、抗菌和快速止血能力的多功能纤维素基仿生水凝胶。本项目详细研究了胶黏剂的化学结构与胶合性能的关系，阐明了引入基团类型和含量等对胶黏性能的影响机制，为纤维素基多巴仿生胶黏剂在能源、环境和生物医疗等领域中的应用提供了理论与技术支撑。