硬段类型和含量对嵌段聚氨酯脲性能的影响

以聚己二酸乙二醇-丙二醇酯二醇(PEPA)为软段,分别采用4种二胺扩链剂和3种二异氰酸酯为硬段,通过预聚体法合成了一系列不同硬段结构和含量的聚氨酯脲弹性体,并采用红外光谱、热失重分析、差示扫描量热和拉伸测试等手段,研究了硬段类型及含量对聚氨酯脲性能的影响。结果表明,在软段结构一致,硬段含量接近的情况下,兼具柔性和刚性的硬段有助于提升聚氨酯脲的力学性能、热学性能和微相分离程度。几种二胺扩链剂和二异氰酸酯中,由二苯基甲烷二异氰酸酯(MDI)和4,4'-二氨基二苯醚(ODA)构成的硬段性能最佳;在软、硬段结构一致的情况下,硬段含量对聚氨酯脲性能影响明显。随着硬段含量增加,聚氨酯脲的拉伸强度、微相分离程度先增大后减小,5%热失重温度和断裂伸长率逐渐下降。当PEPA/MDI/ODA摩尔比为1∶0.5∶0.5(硬段含量31.7%),聚氨酯脲拉伸强度达51.5 MPa,断裂伸长率为709%,5%热失重温度为282.7℃,性能最佳。

Effect of Hard Segment Structure and Content on Properties of Block Polyurethane Ureas

A series of block polyurethane ureas based on different hard segment structures and contents were prepared,using PEPA as soft segment,four diamine chain extenders and three diisocyanates as hard segment.Effect of hard segments on the properties of PUUs were investigated by FT-IR,TG,DSC and stretching test.The results show that hard segments with flexible and rigid structures can improve mechanical properties as well as thermal properties and micro-phase separation of PUUs under conditions of the same soft segment structure and similar hard segment contents.PUU samples with MDI and ODA as hard segment exhibit best properties.Additionally,hard segment contents show obvious effect on properties of PUUs with the same soft and hard segment structures.With the increase of hard segment content,the tensile strength and micro-phase separation increase first and then decrease,while the 5%mass loss temperature and elongation at break decrease.The PUU sample prepared with the mole ratio of PEPA/MDI/ODA 1∶1∶1(the hard segment content of 31.7%),exhibits best properties such as the tensile strength of 51.5 MPa,elongation at bread of 709%and 5%mass loss temperature of 282.7℃.