Influence of network density on the strain hardening of PMMA copolymers

Introduction The intrinsic toughness of glassy polymers depends on the post-yield behavior, on strain softening and strain hardening. Dependent on the loading condition, the macroscopic response to deformation might be brittle, e.g. for poly(methyl methacrylate) (PMMA) and polystyrene (PS) (Fig. 1). Polycarbonate (PC) is ductile, since it necks in tensile testing. Commercial PMMA always contains some copolymer to reduce unzipping and facilitate processing, e.g. ethyl acrylate (EA). Network density and strain hardening can be influenced by addition of EA.