Preparation of Room-Temperature Healable Polyurethanes Based on Synergistic Hydrogen Bonds/Disulfide Bonds and Study on Their Properties
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 re-action.The effects of monomer ratio and molecular structures of chain extenders on the mechanical and self-healing proper-ties 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/m3,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.
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