Strain hardening of polycarbonate in the glassy state: influence of temperature and molecular weight

This study is concerned with the temperature and molecular weight dependenceof the strain-hardening behavior of polycarbonate. It is shown that the strain-hardening modulus reduces with increasing temperature and decreasing molecularweight. This result is interpreted in terms of temperature accelerated relaxationof the entanglement network. Moreover, it is shown that frozen-in orientations, in-duced by homogeneous deformations above the glass transition temperature, leadto anisotropic yield behavior that can be fully rationalized (and modelled) in termsof a superimposed stress contribution of the pre-strained network.