Abstract:
In some extreme environments, polymers are easy to suffer from irreversible damage or degradation, which increases potential safety problems and reduces the service life of the materials. Regarding to the problem of low self-healing rate of the polymer at low temperature, the polymer network with cross-linked multiple hydrogen bonds was prepared by mixing up the polydimethylsiloxanes with amino-terminated flexible molecular chains and malonyl chloride, which were subjected to condensation polymerization at the temperature of −5 ℃ and in Ar atmosphere. The flexible molecular chain effectively reduces the glass transition temperature (
Tg≈−120 ℃), indicating that the molecular chain's ability to move still exists under the low temperature conditions, and it is a prerequisite for polymers to self-heal under low temperature conditions. The results show that the self-healing efficiency of the tensile strength of the polydimethylsiloxane cross-linked polymer at −25 ℃ after 40 min is as high as 97%. Through the reversible fracture and formation of multiple hydrogen bonds between N—H and C=O, the rapid self-healing of polymers at room temperature and high-efficiency self-healing at low temperature can be achieved. This study will provide an insight for further preparation of the autonomous self-healing materials under the extreme environments in the future.