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-freq uency Raman scattering (LFRS). As previously observed for poly(methyl methacrylate) (PMMA), an excess appears in the low-frequency part of L FRS spectra after plastic deformation. The excess is stronger in the c ase of PC than in the case of PMMA, and its light polarization, relati ve to the molecular orientation, is different. In the frame of a non-c ontinuous glassy polymer network, the experimental results are interpr eted by an orientation of macromolecular strands in the less cohesive zones of the polymer matrix, between the more cohesive regions. When t he deformation is carried out at a temperature lower than the glass tr ansition temperature, the more cohesive regions are not affected by th e plastic deformation. It is no more the case when the polymer is defo rmed at a temperature higher than T-g.