APPLICATION OF A NEW METHOD FOR THE DETER MINATION OF STRUCTURAL PARAMETERS OF WET CRAZES TO GAIN INSIGHT INTO THE MECHANISM OF SOLVENT CRAZING IN POLYMERS

The density of solvent-crazed samples of PET, PC, and PVC was shown to increase linearly with an increase in tensile strain. These observati ons and experimental data obtained by small-angle X-ray scattering all owed one to estimate the density pf and the draw ratio hf of the orien ted polymer in craze fibrils for ''wet'' solvent-crazed polymer sample s. For amorphous and annealed PET samples with different degrees of cr ystallinity, these parameters were found to be quite similar. This evi dence suggested that the polymer transition to fibrillar state in the crazes is associated with dramatic structural rearrangements in superm olecular structure of the initial unoriented polymer material. Some co mplicated features of solvent crazing in PVC containing modifying addi tives were discussed.