Experimental characterization and thermoviscoelastic modeling of strain and stress recoveries of an amorphous polymer network

• Experimental strain and stress recoveries of shape memory polymer.
• Finite strain viscoelasticity coupled with time–temperature superposition model.
• Model parameters based on standard polymer behavior characterization.
• Model predicts strain and stress recoveries for various testing parameters.

An acrylate polymer network was submitted to thermomechanical shape memory cycles. The set of experiments characterized the material stress-free strain recovery and the strain-constrained stress recovery in uniaxial tension. Experimental parameters like temperature of strain fixation, amount of strain and heating rate, were varied in order to provide a relatively complete set of experimental data. A model combining the amorphous polymer viscoelasticity and its time–temperature superposition property was used to predict the shape memory behavior of the acrylate polymer network. All the model parameters were characterized using classical tests for mechanical characterization of polymers, which do not include shape memory tests. Model predictions obtained by finite element simulations compared very well to the experimental data and therefore the model relevance for computer assisted application design was assessed.