三聚氰胺树脂π-π堆积超分子自组装增韧机理研究

Melamine formaldehyde resins possess several advantages, such as good flame retardancy, thermal stability, water resistance and mechanical properties, and also have been widely used in manufacturing products of industry. However, the cured resins have poor toughness and impact resistance, which limits the using range of products to a large extent and affects its quality. The traditional modification methods to improve toughness of melamine formaldehyde resins are not fundamentally considering its cause of brittleness. The idea is just limited to add modification, such as introducing the flexible material, increasing the network chain length and reducing the crosslinking degree of the resin molecules, which cannot tangibly improve the toughness of melamine formaldehyde resins. Beginning with molecular spatial structure, supramolecular assemblies of triazine rings π-π stacking was built to improve the toughness of melamine formaldehyde resins in this project. The conditions of formation, control mechanism and control methods of triazine rings π-π stacking and the mechanism of improving the toughness of melamine formaldehyde resins by π-π stacking were studied by the theory of quantum chemistry calculation, chemical derivation and experimental verification. The purpose of this study was to achieve the orientation preparation of the flexible melamine formaldehyde resins.

三聚氰胺树脂具有优异的阻燃性、热稳定性、防水性及良好的机械性能等优点，被广泛应用于工业生产的各个方面。但三聚氰胺树脂固化层脆性较大和耐冲击性能力较差，这在很大程度上限制了产品的使用范围，并且影响其使用质量。传统的三聚氰胺树脂增韧改性方法未从根本上考虑其脆性产生的原因所在，其基本出发点仅限于添加改性，引进柔性物质、增加分子内网络链长、降低树脂分子的交联度等，对三聚氰胺树脂的韧性提高幅度有限。本研究从分子空间结构着手，主要通过构筑三嗪环π-π超分子在树脂中的堆积来实现对三聚氰胺树脂的增韧。研究中结合量子化学计算、化学理论推导和试验验证，掌握三嗪环π-π堆积在三聚氰胺树脂体系的构筑条件、调控机制和控制方法，解析三嗪环π-π堆积增韧三聚氰胺树脂的机理，实现柔韧型三聚氰胺树脂的定向制备。

本研究针对三聚氰胺树脂固化层脆性较大和耐冲击性能较差的问题，从分子空间结构着手，主要通过构筑三嗪环π-π超分子堆积来实现对三聚氰胺树脂的增韧改性。项目从组成三聚氰胺树脂基本结构单元间的基元反应出发，结合量子化学计算、化学理论推导和试验验证，从微观层面揭示三嗪环π-π堆积的宏观构筑条件和控制方法。本项目的执行，明确了甲醛浓度、碱催化、聚合度、初始碱性阶段摩尔比及终摩尔比对三嗪环π-π堆积的积极作用，并以此指导三嗪环π-π堆积型三聚氰胺树脂的合成。在此基础上，联合聚乙二醇、聚酰胺、无机材料、生物质材料及固化技术优化对三聚氰胺树脂进一步增强增韧。改性后的三聚氰胺树脂具有较高的力学性能和耐热性能、较低的游离甲醛，且具有显著的韧性断裂特征，韧性最大提高幅度达500%。项目的研究成果可为强韧型三聚氰胺树脂的制备提供理论指导。. 自项目实施以来，已正式发表相关研究论文10 篇。申请发明专利3项，已授权1项，另2项已进入实审。培养硕士研究生4人，2人晋升上一级职称，2人入选省级人才项目。