硬段结构对含二硫键自修复聚氨酯性能的影响

Effect of Hard Segment Structure on Properties of Self-Healable Polyurethane Containing Disulfide Bonds

硬段结构的研究对指导制备兼顾力学性能与自修复性能的聚氨酯弹性体具有重要的意义。文中分别以4,4'-二苯基甲烷二异氰酸酯(MDI)、4,4'-二环己基甲烷二异氰酸酯(HMDI)、甲苯二异氰酸酯(TDI)、异佛尔酮二异氰酸酯(IPDI)及双(2-羟基乙基)二硫醚(HEDS)为硬段部分,聚己内酯二元醇为软段部分,制备了一系列含脂肪族二硫键的自修复聚氨酯,探究了不同异氰酸酯、硬段含量和扩链剂对其力学性能与自修复性能的影响。结果表明,对于异氰酸酯结构来讲,脂环族异氰酸酯制备的自修复聚氨酯具备更好的力学性能与自修复性能;对于脂环族异氰酸酯体系聚氨酯的硬段含量而言,一定范围越高,二硫键与氢键的含量也越高,越有利于材料的力学性能与自修复性能;对于扩链剂结构来讲,脂肪族二硫键主要是促进较高温度条件下的自修复性能,对于室温自修复性能起到的作用有限。

It is important to study hard segment structure for preparing polyurethane elastomer which simultaneously has optimized mechanical and superior self-healing properties.In this work,methylene diphenyl diisocyanate(MDI),4,4'-methylenebis(cyclohexyl isocyanate)(HMDI),tolylene-2,4-diisocyanate(TDI),isophorone diisocyanate(IPDI),and 2-hydroxyethyl disulfide(HEDS)were chosen as hard segment and polycaprolactone diol was chosen as soft segment to synthesis a series of self-healable polyurethanes containing aliphatic disulfide bonds.The regularity of mechanical and self-healing properties was explored in terms of different isocyanates,hard segment contents and chain extender.These results suggest that the self-healable polyurethane with alicyclic has preferable mechanical and self-healing properties.As the hard segment content of polyurethanes based on alicyclic isocyanate increases under range conditions,the content of disulfide and hydrogen bonds increases,which is favorable to simultaneously promote mechanical and self-healing properties.Aliphatic disulfide bonds mainly promote self-healing properties at higher temperatures,but have a limited effect on self-healing properties at room temperature.