Structure of Multinetwork Elastomer: Comparison with Hydrogen Bond Cross-Linking Elastomer

Earlier, we developed a multinetwork elastomer (MNE) by using a covalent bond, hydrogen bond, and clay plane bond. By taking advantage of the characteristics of each cross-linking, the thermoplastic elastomer shows excellent compression set resistance (indicators of how much it recovers when the rubber is compressed), good flowability, and high tensile properties. In the previous report, it was thought that the cross-linked part was hydrogen bonded to the end face of the clay. However, it was estimated that the cross-linked part also has ion-dipole interaction with ammonium cations and/or anionic parts on the clay surface by further structural analysis, and a new estimated structure was proposed. In addition, it was found that the addition effect of organic clay was a specific phenomenon in the MNE from the comparison with the hydrogen bond cross-linking elastomer (HBE). In a HBE that expresses physical properties only by the hydrogen bond, the interaction between the clay and the hydrogen bond cross-linkage weakened the hydrogen bond cross-linking between polymers to cause deterioration of the physical properties. However, in the MNE with stable covalent cross-linking, cross-linking does not change, and the hydrogen bond cross-linking site interacts with the clay surface to cause nonlocalization of the cross-linking part. Therefore, the physical properties have been improved.