Multi-Network Elastomer Coexisting between Thermoplasticity and Creep Resistance

In general, since rubber has a weak interaction between molecular chains, if it is not crosslinked, it will flow and cannot withstand actual use. Covalent crosslinked rubber has high mechanical strength properties due to the strong bonding force of crosslinking, but it is difficult to reshape and recycle because of the difficulty to cleave the crosslink. Meanwhile, thermoplastic elastomers use physical interactions between molecular chains to suppress fluidity and express physical properties. Although it can be reshaped by disconnecting the physical crosslink due to heat, it lacks heat resistance. Earlier, by crosslinking with strong hydrogen bonds, we developed a thermoreversible crosslinked rubber with physical properties similar to vulcanized rubber. However, the creep resistance was not at a satisfactory level because the hydrogen bond was recombined. Therefore, we developed a multi-network elastomer that introduces three types of cross-linking: covalent bonding, and clay-plane bonding, in addition to hydrogen bonding. This elastomer showed high strength and high creep resistance while being thermoplastic.