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Renewable polymers with excellent stretchability and self-healing ability are interesting for a wide range of applications. A novel type of wholly biobased, self-healing, polyamide-based thermoplastic elastomer was synthesized using a fatty dimer acid and a fatty dimer amine, both containing multiple alkyl chains, through facile one-pot condensation polymerization under different polymerization times. The resulting elastomer shows superior stretchability (up to 2286%), high toughness, and excellent shape recovery after being stretched to different strains. This elastomer also displays high room-temperature autonomous self-healing efficiency after fracture and zero water uptake during water immersion. The highly entangled main chain, the multiple dangling chains, the abundant reversible physical bonds, the intermolecular diffusion, and the low ratio of amide to methylene group within the elastomer are responsible for these extraordinary properties. The polymerization time influences the properties of the elastomer. The use of the optimal self-healing thermoplastic elastomer in anticorrosion coating, piezoresistive sensing, and highly stretchable fibers is also demonstrated. The elastomer coating prevents stainless-steel products from corrosion in a salty environment due to its superhydrophobicity. The elastomer serves as a robust flexible substrate for creating self-healing piezoresistive sensors with excellent repeatability and self-healing efficiency. The elastomer fiber yarn can be stretched to 950% of its original length confirming its outstanding stretchability.

Suspensions containing 8 and 10 wt% polyacrylonitrile (PAN) and 1, 2, 3, 5, 7 and 10 wt% graphene oxide (GO) were prepared using a special mixing routine and fibres were generated from these mixtures by pressurised gyration. The combination of pressure and gyration speed was effective in controlling the fibre morphology and fibre diameter which ranged from 1 to 20 μm. Fibres were pyrolysed to remove the polymer and only the 10 wt% PAN fibres survived. The microstructure of the pre- and post-pyrolysis products were characterised by scanning electron microscopy, both with and without focussed ion beam etching, Fourier-transformed infrared and Raman spectroscopies. Pyrolysed fibre electrical conductivities were measured and only those containing 1 and 2 wt% GO were conductive.

A simple and effective process combining pressure and gyration has been developed and used to jet-out composite fibres containing graphene nanoplatelets. Thermoplastic polyurethane and phenolic resin polymers were used as matrices. Processing parameters such as rotation speed, pressure and polymer concentration had a marked influence on the composite fibre diameter. Focussed ion beam milling and etching verified the effective incorporation of the graphene nanoplatelets into the composite fibres. Morphological, rheological, physico-chemical and thermal properties of the composite fibres were evaluated to identify possible applications for them.