分子结构中碳碳双键对水性UV聚氨酯分散体的影响

摘要

A UV curable waterborne epoxy modified polyurethane dispersion with 50% solid content was synthesized with isophorone diisocyanate (IPDI) , polyester diol (PBA) as the main raw materials. Reaction of OH groups in hydroxypropyl acrylate (HPA) and pentaerythritoltriacrylate (PETA) and NCO groups in polyurethane prepolymer formed carbon - carbon double bonds, leading photosensitive. The tensile strength, hardness, particle size and other performance of UV curing waterborne polyurethane films were investigated. Additionally, the dynamic mechanical analysis ( DMA) and cross section structure characterization with SEM of the coating films were tested. The results showed that when the double bond content increased, the tensile strength and hardness of UV coating increased with other properties unchanged. DMA tests showed that when the content of double bond decreased, the Tt(s) of soft segment shifted to low temperatures, and the Tg(h) of hard segment shifted to the high temperature, thus the phase separation tended to be completed. SEM tests showed that when the degree of cross - linked resin increased, the degree of resistance to fracture also increased.%采用异佛尔酮二异氰酸酯(IPDI)、聚酯二元醇(聚己二酸-1,4丁二醇酯)(PBA)为主要原料合成了环氧改性的、固体分约为50％的水性紫外光固化聚氨酯分散体(PUD).通过预聚物中聚氨酯分子末端的-NCO基团与丙烯酸羟丙酯(HPA)和季戊四醇三丙烯酸酯(PETA)上的羟基发生反应,从而引入碳碳双键,使PUD具备紫外光固化的性能.研究了水性UV分散体的碳碳双键对水性聚氨酯的拉伸强度、硬度、粒径等性能方面的影响,同时对涂膜进行动态力学性能测试(DMA)和断面结构表征(SEM).结果表明:双键含量增加,UV涂料的拉伸强度和硬度增大,分散体和涂料的其他性能基本不变；DMA测试表明随着双键含量的减小,软段的Tg(s)移向低温,硬段的Tg(h)移向高温,相分离趋于完全；SEM测试表明树脂的交联程度越大,抵抗断裂的程度也越大.