State Key Laboratory for Modification of Chemical Fibers and Polymer Materials，College of Material Science and Engineering，Donghua University，Shanghai 201620，China
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 selfhealing 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 selfhealing 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 selfhealing 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/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．