氢键/二硫键协同的室温修复聚氨酯的制备及性能研究

Preparation of Room-Temperature Healable Polyurethanes Based on Synergistic Hydrogen Bonds/Disulfide Bonds and Study on Their Properties

自修复材料作为一类新兴的智能材料,具有广泛的应用前景,然而此类材料难以兼具良好的力学性能与自修复能力。以聚四氢呋喃(PTMEG)为软段、异佛尔酮二异氰酸酯(IPDI)和双(4-羟苯基)二硫醚(4-HD)为扩链剂共同构成硬段,通过两步扩链反应制备了室温自修复聚氨酯(PUHD),并分别研究了单体配比与扩链剂的分子结构对PUHD的力学与自修复性能的影响。结果表明:当R值(R=[IPDI]/[PTMEG])为1.5时,PUHD的综合性能最佳,拉伸强度、断裂伸长率与韧性分别为7.53 MPa、1447.80%与31.98 MJ/m^(3)。PUHD-1.5具有良好的流变性能,在25与60℃下的特征弛豫时间分别为23.45与7.10 min,在25℃下修复6 h,断裂伸长率与拉伸强度的修复效率分别为95.29%和89.95%。扩链剂的分子结构对PUHD的自修复性能有显著影响,弱氢键作用与松散堆积的硬段有利于提高PUHD的自修复性能。

As a new kind of intelligent material,self-healing materials have a widespread application prospect.However,it is difficult to have both good mechanical properties and self-healing ability.Here,using polytetrahydrofuran(PTMEG)as soft segments,isophorone diisocyanate(IPDI)and bis(4-hydroxyphenyl)disulfide(4-HD)as chain extenders constructing hard segments together,a room-temperature self-healing polyurethane(PUHD)was prepared by two-step chain extension reaction.The effects of monomer ratio and molecular structures of chain extenders on the mechanical and self-healing properties of PUHD were studied.The results showed that PUHD had the best comprehensive performance when the R value(R=[IPDI]/[PTMEG])is 1.5.The tensile strength,elongation at break and toughness reached 7.53 MPa,1447.80%and 31.98 MJ/m^(3),respectively.PUHD-1.5 had good rheological properties with characteristic relaxation time of 23.45 and 7.10 min at 25 and 60℃,respectively.The self-healing efficiency of elongation at break and tensile strength were 95.29%and 89.95%at 25℃for 6 h,respectively.The molecular structures of chain extenders have a significant effect on the self-healing ability of PUHD.Weak interaction of hydrogen bonds and loosely-packed hard segments are beneficial to improve the self-healing properties of PUHD.