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

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 T-g values (32-142 degrees 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.

Automated summary

Aromatic disulfide-based vitrimers demonstrate elasticity-driven shape-memory and plastic reprocessability through the rearrangement of dynamic covalent crosslinks. The key temperatures for triggering phase transition and disulfide exchange reaction are highly sensitive to the molecular structure of the polymer. The relationship between structure, dynamics, and shape-changing properties was investigated through the synthesis of five networks with varying T-g values, molecular structures, and crosslink densities.