Crack healing and reclaiming of vulcanized rubber by triggering the rearrangement of inherent sulfur crosslinked networks

Abstract

Vulcanized rubber made from an industrial formula can be healed and reclaimed by activating the rearrangement of the inherent sulfur crosslinked networks under the catalysis of CuCl2.

Sunlight driven self-healing, reshaping and recycling of a robust, transparent and yellowing-resistant polymer

“…Recycling of dynamically bonded polymers through heat or water stimulus has been reported elsewhere, 21,22,[35][36][37][38][39][40][41] but the application of light stimulus in this aspect has not yet been reported to our knowledge. The benefit of sunlight triggered disulfide exchange is also reflected by the ability of reshaping of PU-HEDS-400.…”

Autonomic healable waterborne organic-inorganic polyurethane hybrids based on aromatic disulfide moieties

“…Among the different healing alternatives reported in literature, disulfide metathesis was selected as the reaction to provide healing characteristics to our waterborne polyurethane structures. This dynamic reaction is known to provoke the exchange of the side groups of the disulfide bridges in the presence of initiators or catalysts [5][6][7][8]. Once incorporated in the polymer network, these structures are capable of breaking and reforming linkages, and, as a consequence, these materials act as vitrimers, that is, solid polymers during their lifetime that under certain conditions can flow and thereby promote material healing [2,[9][10][11][12].…”

Stress intensification – an abnormal phenomenon observed during stress relaxation of dynamic coordination polymer

“…Nevertheless, it is worth noting that dynamically bonded polymers do not necessarily exhibit similar stress intensification manner. As mentioned in the Introduction, the stress applied to the polymers crosslinked by dynamic reversible bonds (like disulfide, C-ON and aromatic Schiff base bonds) used to relax to zero [3][4][5][6][7][8][9]. It might be attributed to the fact that these polymers lack the mechanism of increasing crosslinks during stress relaxation.…”

“…From the phenomenological point of view, linear polymers can completely relax stress to zero provided time is long enough, while crosslinked polymers can only relax stress to a certain equilibrium value owing to the network confinement. However, if the crosslinked polymers are built up by reversible bonds, as revealed by recent investigation [3][4][5][6][7][8][9], rearrangement of the networks would be allowed when the reversible reaction is triggered. The materials also go to a lower state of energy, leading to complete relaxation of the stress.…”