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Design and development of self‐repairable and recyclable crosslinked poly(thiourethane‐urethane) via enhanced aliphatic disulfide chemistry
Author(s) -
Liu Qing,
Liu Yibin,
Zheng Hua,
Li Chunmei,
Zhang Yi,
Zhang Qiuyu
Publication year - 2020
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20190186
Subject(s) - polysulfide , thermosetting polymer , elastomer , materials science , polymer , toughness , monomer , disulfide bond , curing (chemistry) , polymer chemistry , stress relaxation , thermal stability , composite material , chemical engineering , chemistry , organic chemistry , biochemistry , creep , electrode , engineering , electrolyte
Thermoset polymer elastomers that are capable of autonomous repairability upon physical damage at ambient temperature are highly desirable because of their thermal and environmental resistance, outstanding mechanical toughness and stability. To aim at this goal, we demonstrated that tris(diethylamino)phosphine was initially proven as an efficient catalyst for the aliphatic disulfide exchange at mild condition. By making use of the aliphatic disulfide bond reshuffling and elasticity of polyurethane elastomers, the inherently cross‐linked polysulfide‐based poly(thiourethane‐urethane) elastomers were prepared and exhibited the ability to mend without extrinsic stimuli in the presence of phosphorus catalyst at room temperature after artificially damaged. The self‐healing efficiency via the mechanical recovery approach was investigated to be mainly dependent upon the cross‐linking density of polysulfide and hard segments chemistry, which in turns determined the molecular chain diffusion and reshuffling that was corroborated by the stress‐relaxation study. The thermoset elastomer based on asymmetric diisocynate showed a maximum self‐healing efficiency of 85.6% compared to 71.6% for the elastomer with symmetric monomer building blocks. The self‐healable polymer was confirmed to be recyclable and reprocessable through a cut‐compression processing cycle under a quite mild pressure and temperature thanks to the disulfide bond reshuffling. Meanwhile, the recycled thermoset elastomer well maintained the mechanical properties to its original material.