A self-healing sulfur vulcanized natural rubber (NR) is here reported using the common ingredients in a traditional NR formulation. The dynamic character of the di- and polysulfide bonds naturally present in covalently cross-linked rubbers was found to be responsible for the healing ability and the full recovery of mechanical properties at moderate temperatures provided the material was employed in a nonfully cured starting state. Results show that a compromise between mechanical performance and healing capability can be reached by tailoring the amount of sulfur, the cross-linking density, and the disulfide/polysulfide ratio. The healing efficiency was found to depend on the postcuring storage time, the time between damage creation and re-establishment of mechanical contact, and the actual healing time. Furthermore, a dedicated electron spin resonance (ESR) test allowed establishing the underlying healing principle based on temperature-induced free sulfur radicals. The main observations presented here can serve as the basis for the design and preparation of other self-healing polymers with long-term durability based on di-/polysulfide bridges and other reversible moieties

The rapid utilization of carbon fibre reinforced composite (CFRC) and glass fibre reinforced composite (GFRC) in main sectors, such as automobile, aerospace, wind turbines, boats and sport parts, has gained much attention because of its high strength, light weight and impressive mechanical properties. Currently, the increasing amount and handling of composite waste at their end-of-life (EoL) has a negative impact on resources conservation and the environment. Pyrolysis, a two-step process, appeared as most viable process to recover not only valuable materials but also produce fuel and chemicals. However, the testing facilities and optimized operation of composite waste in pyrolysis processes to produce materials with low energy consumption and acceptable mechanical properties are still under development and discussion before commercialization. The aim of this article is to review the studies on CFRC/GFRC recycling via pyrolysis processes and highlight their technical challenges and re-use possibilities in high performance composites. The forthcoming commercialization challenges and respective market potential to recyclates using the pyrolysis process will be addressed. This study will also introduce the strong connection between recycling and re-usability of fibres which would help to explain the concept of circular economy and cradle-to-cradle approach. Finally, based on updated studies and critical analysis, research gaps in the recycling treatments of fibrous composite waste using pyrolysis processes are discussed with recommendations.

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The dump temperature and mixing interval between rubber, silica and silane coupling agent for silica-filled natural rubber (NR) tire tread compounds using bis-triethoxysilylpropyl tetrasulfide (TESPT) as silane were optimized. The dump temperature turns out to be the key parameter governing the properties of the silica-filled NR compounds. The increase in

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