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Aromatic disulfide based vitrimers show elasticity driven shape-memory and plastic reprocessability via associative rearrangement of dynamic covalent crosslinks. Those processess represent the two sides of a coin: the storage and relaxation of the strain energy caused by a deformation load. The key temperatures that trigger the underlying mechanisms, i.e. phase transition and disulfide exchange reaction, are extremely sensitive to the molecular structure of the polymer and under certain condition overlap. To gain insight on the relationship between the structure, dynamic and shape-changing properties, five aromatic disulfide-based epoxy networks with a range of Tg values (32–142 °C), molecular structure and crosslink densities (2252–462 mol m−3) were synthesized. The epoxy matrices were formulated combining different ratios of rigid bisphenol A diglycidyl ether (DGEBA) and flexible poly(propylene glycol) diglycidic ether (DGEPPG) epoxy monomers crosslinked by 4-aminophenyldisulfide hardener.

Novel rheological features and conductivity results of irradiated PP/MWCNT nanocomposites are presented. Elongational flow measurements reveal a strain hardening behaviour which is compatible with the creation of long chain branched macromolecules provoked by irradiation. However, oscillatory shear flow results suggest that irradiation does not affect interactions of MWCNTs with PP chains. The addition of carbon nanotubes brings about conductivities of the order of 10 −2 S/cm, but its scavenger effect reduces the number of radicals generated by irradiation, lessening the strain hardening effect. The employed mixing method provides a dispersion of MWCNTs in a PP matrix, which followed by an ad hoc irradiation, allows obtaining an electrical conductive polypropylene with a strain hardening behaviour. The obtained results open novel routes to conductive nanocomposites apt to be processed using methods discarded for linear PPs, such extrusion-blowing and others.