Dual-Responsive Self-Healable Carboxylated Acrylonitrile Butadiene Rubber Based on Dynamic Diels-Alder "Click Chemistry" and Disulfide Metathesis Reaction

Introduction of the self-healing property in the commercially available elastomers promotes the development of high-end elastomeric products with an extended lifespan. Herein, a smart functionalized carboxylated nitrile rubber (XNBR) is prepared based on dynamic phototriggered disulfide metathesis and thermoreversible Diels-Alder (DA) "click chemistry." In this case, the XNBR is functionalized with furfuryl amine (FA) followed by crosslinking with a dual functional crosslinker having a maleimide as well as a disulfide functionality for participating in the DA reaction and to induce the UV-triggered disulfide metathesis reaction, respectively. The self-healing properties are studied by thermal, mechanical, and microscopy analyses. The crosslinked materials present an impressive self-healing efficiency of approximate to 88% and a tensile strength of approximate to 10 MPa without affecting its oil-resistance property whereas pristine XNBR and furfuryl-functionalized XNBR (FXNBR) show tensile strengths only 0.4 and 0.6 MPa, respectively. Furthermore, the crosslinked rubber is demonstrated to be recyclable, without much loss of its mechanical properties. In a nutshell, the use of this smart dual pathway of self-healing can pave a new direction in sustainable development in NBR elastomers.