Finite viscoplasticity of amorphous glassy polymers in the logarithmic strain space

Modeling the viscoelastoplastic behavior of amorphous glassy polymers

Constitutive equations are derived for the viscoelastoplastic response of amorphous glassy polymers at isothermal loading with small strains. A polymer is treated as an ensemble of cooperatively relaxing regions (CRR) which rearrange at random times as they are thermally agitated. Rearrangement of CRRs reflects the viscoelastic response of the bulk medium. At low stresses, CRRs are connected wi...

Diffusion of Small Molecules in Amorphous Glassy Polymers

Viscoplasticity and large-scale chain relaxation in glassy-polymeric strain hardening.

A simple theory for glassy-polymeric mechanical response that accounts for large-scale chain relaxation is presented. It captures the crossover from perfect-plastic response to Gaussian strain hardening as the degree of polymerization N increases, without invoking entanglements. By relating hardening to interactions on the scale of monomers and chain segments, we correctly predict its magnitude...

Finite-size corrections for logarithmic representations in critical dense polymers

Article history: Received 16 December 2011 Received in revised form 16 February 2012 Accepted 17 March 2012 Available online 19 March 2012 Editor: L. Alvarez-Gaumé We study (analytic) finite-size corrections in the dense polymer model on the strip by perturbing the critical Hamiltonian with irrelevant operators belonging to the tower of the identity. We generalize the perturbation expansion to ...

Amorphous-amorphous transition in glassy polymers subjected to cold rolling studied by means of positron annihilation lifetime spectroscopy.

In this study, polycarbonate (PC) and polystyrene (PS) are subjected to plastic deformation by means of cold rolling and the resulting variation of the free volume and its subsequent time evolution after rolling is investigated by means of positron annihilation lifetime spectroscopy (PALS). The value of the long lifetime component that is attributed to the decay of ortho-positronium (tau(o-Ps))...