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为了提高水性聚氨酯耐水性等性能,以异佛尔酮二异氰酸酯(IPDI)、聚四亚甲基醚二醇(PTMG)、二羟甲基丙酸(DMPA)、1,4-丁二醇(BDO)等为原料,二月桂酸二丁基锡(DBTDL)为催化剂,通过预聚体法合成了单端封闭的聚氨酯预聚体(PPU),然后以一代端羟基树枝状聚合物(PAMAM-OH)为核,通过接枝共聚法制备了树枝状水性聚氨酯(HWPU)。通过单因素分析法优化出PPU的最佳合成条件:反应时间为2 h,反应温度为80℃,n(NCO)∶n(OH)为6∶1。采用FIIR、XRD和纳米粒度表面电位分析仪对产物的结构和性能进行了表征,并对胶膜的耐水性、表面粗糙度和力学性能进行了测试。结果表明:HWPU乳液粒径为43.56 nm,胶膜结晶度为1.59%,胶膜24 h的吸水率为4.8%,拉伸强度为39.2 MPa,断裂伸长率为376.4%,胶膜表面粗糙度降低。与未加PAMAM-OH的水性聚氨酯(WPU)相比,HWPU的吸水率降低了67.1%,拉伸强度提高了74.2%,耐水性和拉伸强度得到明显提高。
In order to improve the water resistance and other properties of water-borne polyurethanes, polybutylene succinate (IPDI), polytetramethylene ether glycol (PTMG), dimethylolpropionic acid (DMPA) BDO) as raw materials, dibutyltin dilaurate (DBTDL) as catalyst, one-terminal closed polyurethane prepolymer (PPU) was synthesized by prepolymer method. As the core, dendritic waterborne polyurethane (HWPU) was prepared by graft copolymerization. The optimum synthesis conditions of PPU were optimized by single factor analysis: the reaction time was 2 h, the reaction temperature was 80 ℃, the n (NCO): n (OH) was 6:1. The structure and properties of the product were characterized by FIIR, XRD and nano-particle surface potential analyzer, and the water resistance, surface roughness and mechanical properties of the film were tested. The results showed that the particle size of HWPU emulsion was 43.56 nm, the crystallinity of the film was 1.59%, the water absorption of the film was 4.8%, the tensile strength was 39.2 MPa, the elongation at break was 376.4%, the surface roughness reduce. Compared with WPU without PAMAM-OH, the water absorption of HWPU decreased by 67.1%, the tensile strength increased by 74.2%, and the water resistance and tensile strength were significantly improved.