Generally, self-healing research based on commercial rubber is of great significance in sustainable development by extending the lifetime of materials. However, it is still a great challenge so far to prepare recyclable rubber that combine excellent self-healing properties with good mechanical strength and is also recyclable. Herein, we report the use of epoxidized natural rubber (ENR), a reactive polymer presenting dual functional groups (unsaturated double bonds and epoxy sites) available for cross-linking, to prepare a dual cross-linked self-healing ENR based on dynamic disulfide metathesis and thermoreversible hydrogen bonding. Specifically, different structures of aromatic disulfide compounds are introduced into the same system to promote the disulfide metathesis and thus improving the self-healing efficiency of the material. As a result, the dual cross-linked ENR shows high mechanical strength (9.3 ± 0.3 MPa), high self-healing efficiency (up to 98%), and ideal recyclability. In addition, cyclic fatigue tensile test shows that the self-healing properties of the present material are not affected by the damage forms, whether it is complete fracture or cyclic fatigue damage. These outcomes are expected to promote the development of self-healing technology in the sustainable application of cross-linked rubber materials.

There is a trade-off between mechanical and self-healing performance for crosslinked self-healing materials. Herein, we design a polyurethane material containing triple synergy dynamic bonds to address the dilemma. The as-prepared polyurethane exhibits a maximum stress of 27.3 MPa and excellent self-healing performance. Specifically, boric acid is used as a cross-linker and the network cross-linked with boronic ester bonds under alkaline conditions is highly beneficial in terms of mechanical properties. Meanwhile, disulfide bonds and reversible boronic ester bonds located at the cross-linked point and main chain are successively broken upon being damaged, which is conducive to better fluidity of chains and endows the material with superior healing efficiency and multiple cycles of healing. Consequently, the high-performance self-healing material is of great potential in the fields of high-performance coating, aerospace, and load-bearing rubber.

While a great diversity of rubber/plastic damping blends have been reported, the damping trough resulted from phase incompatibility, which usually exists between the glass transition temperatures (T g ) of each component, remains an unsolved problem by separating the effective temperature range of damping blends. Herein, we reported a new and facile way of preparing rubber/plastic binary blends with high damping property by eliminating the inherent damping trough. Specifically, we envisaged that peroxides can trigger free radical reactions both within and between epoxidized natural rubber/diallyl phthalate prepolymer moieties, which serve as the co-vulcanizer to generate interphase reactions thus enhancing phase compatibility. Accordingly, apart from the resulting high damping epoxidized natural rubber40/diallyl phthalate prepolymer binary blends with an effective (tan d min > 0.35) temperature range of 178 8C from 233 to 145 8C, the proposal has also been demonstrated via the support of broadband dielectric spectrometer testing, dynamic mechanical analysis, and differential scanning calorimetry.

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