Effect of a plastic deformation on the nanostructure of polycarbonate: Study by low-frequency Raman scattering

The effect of a plastic deformation, induced by a simple shear, on the nanostructure of amorphous polycarbonate (PC), is studied by low-frequency Raman scattering (LFRS). As previously observed for poly(methyl methacrylate) (PMMA), an excess appears in the low-frequency part of LFRS spectra after plastic deformation. The excess is stronger in the case of PC than in the case of PMMA, and its light polarization, relative to the molecular orientation, is different. In the frame of a non-continuous glassy polymer network, the experimental results are interpreted by an orientation of macromolecular strands in the less cohesive zones of the polymer matrix, between the more cohesive regions. When the deformation is carried out at a temperature lower than the glass transition temperature, the more cohesive regions are not affected by the plastic deformation. It is no more the case when the polymer is deformed at a temperature higher than T-g.