Preparation and Characterization of Thermally Reversible Self-healing Polyurethane Elastomer

Abstract

In order to investigate the structure and property relationships of intrinsic self-healing polyurethane and balance the seemly contradictory forces between its self-healing efficiency and mechanical strength, the reversible disulfide bonds were introduced into polyester-polyurethane by taking hexamethylene diisocyanate (HDI) trimers as the cross-linker and 4,4-diamino diphenyl disulfide as the chain-extender. The results show that the optimal self-healing elastomer exhibits a tensile strength of 7.7MPa and a maximum self-healing efficiency of 97.4% at 60℃after 24 hours, whereas the common elastomer synthesized without disulfide bonds (via H-bonding interactions) only exhibits a tensile strength of 9.3MPa and a maximum self-healing efficiency of 58.0% under the same condition, indicating that the existence of disulfide bonds helps to increase the self-healing efficiency by 67.9%. The prepared elastomer is found to have multi time self-healing capabilities and the second time self-healing efficiency is 62.3%.

Keywords

• 4,4-diamino diphenyl disulfide
• hexamethylene diisocyanate trimer
• polyurethane
• intrinsic self-healing
• tensile strength
• thermally reversible