The effect of matrix on shape properties of aromatic disulfide based epoxy vitrimers

“Stress relaxation via aromatic disulfide exchange reactions is highly dependent on the thermo mechanical properties of the network structure and its extent determines the ultimate shape memory and plastic reprocessability that vitrimers exhibit”. [Display omitted] •Aromatic disulfide based epoxy vitrimers show shape-memory and plastic reprocessability.•Aromatic disulfide based vitrimers with a range of crosslinking density, viscoelastic properties, Tg and Tv temperatures.•Network composition and architecture affect dynamic properties.•The shape recovery of the samples can be tuned by inducing partial stress relaxation. 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.