Construction of Silica/Polyurethane/Epoxidised Natural Rubber Vitrimer Biobased Elastomers via Octa-Hydrogen Bonding with Interfacial β-Hydroxy Ester Bonding
Lingfeng Cui, Jing Qiao, Guanyue Zeng, Yuzhu Xiong, Gege Huang, Daiqiang Li
Abstract
Developing biobased rubber composites that simultaneously boost tensile strength and elongation at break while integrating self-healing capacity and reprocessability remains a critical challenge in the rubber industry. Inspired by the unique multiple hydrogen bonding structure of spider silk and the dynamic β-hydroxy ester exchange reaction, this study constructed an epoxy polyurethane rubber containing octuple hydrogen bonds and incorporated it into epoxidized natural rubber. Carboxylated silica was utilized as a bridging agent to form β-hydroxy ester reversible covalent bonds at the interface between the filler and the rubber, thereby designing a high-strength, self-repairing, and reprocessable’vitrimer’ biobased elastomer. This design approach endows the material with outstanding mechanical properties (tensile strength of 8.92 MPa, Young’s modulus of 2.71 MPa, toughness of 17.45 MJ/m 3 ), excellent self-healing performance (healing efficiency of 92.1%), and superior processability (tensile strength recovery of 97.6%). These properties are primarily attributed to the presence of reversible noncovalent octet hydrogen bonds and dynamic covalent β-hydroxy ester bonds. Furthermore, this design can be readily implemented across different biobased epoxy polymers and carboxyl-rich nanofillers. The design concepts presented herein can be applied to the development of self-healing and reprocessable’vitrimer’ biobased elastomers, providing valuable insights for the future design of green and sustainable polymers.