RADIATION EFFECTS OF POLY(VINYLIDENE FLUORIDE) (PVDF) (I) - MECHANISMOF ACCELERATING DAMAGE OF CRYSTAL IN HIGH-DOSE ZONE

The relationship between the crystallinity of poly( vinylidene fluorid e) (PVDF) and electron radiation effects is studied with differential scanning calorimeter and X-ray diffraction. The form of crystal of PVD F is not changed. In the low dose tone (lower than 400 kGy), the cryst allinity of PVDF increases slightly with the increase of absorbed dose , and then decreases slowly, whereas the decrease of the crystallinity is accelerated with the increase of the absorbed dose in high dose zo ne. Gel and Sol properties of irradiated samples of PVDF are also stud ied with extraction of N, N-dimethyl formamide, In a low dose range, i t fits Charlesby-Pinner formula very well; however, with the increase of the dose, it begins to deviate from this formula because of the obs truction of the crystalline region of PVDF.