Radioinduced crosslinking of poly(vinylidene fluoride) (in Japanese)
The radiation-induced crosslinking, chain scission, and oxidation of poly(vinylidene fluoride) (PVdF) have been studied. The irradiation was carried out with gamma rays and electron beams at ambient tempcrature under vacuum and in the presence of oxygen. The gel formation, solution viscosities, and number average molecular weight of the PVdF so treatcd, as well as the evolution of hydrogen fluoride (HF) and other gases were measured. IR and UV spectra were also obtained. When PVdF was irradiated under vacuum, the G value for crosslinking was 0.6 ~ 0.8. This was equal to the G value for chain scission. Double bonds including polyenes were formed as a result of dehydrofluorination. The concentration of polyenes was, however, low and decrcased with increase in the numher of conjugated unsaturation. Polyenes longer than tetraene were hardly observable. The G value for the formation of HF was reduced from 3.5 to 3.0 when HF was removed with dry potassium hydroxide during irradiation. This result suggests the accelerating effect of HF on the radiolytic dehydrofluorination of PVdF. Oxygen accelerated the chain scission and dehydrofluorination of PVdF. Those effects are dependent on dose rate and the thickness of samples. At high dose rate (electron beams), there was little effect, while the remarkable effect was observed at low dose rate; the thinner the sample the more the effect. Carbonyls such as acid fluoride and carboxylic acid were detected as the oxidation products. The reaction mechanism is discussed in connection with the results obtained here and ESR measurement. (auth)
- Research Organization:
- Japan Atomic Energy Research Inst., Takasaki
- NSA Number:
- NSA-29-004901
- OSTI ID:
- 4392841
- Journal Information:
- Nippon Kagaku Kaishi, v. 1973, no. 8, pp. 1574-1581, Journal Name: Nippon Kagaku Kaishi, v. 1973, no. 8, pp. 1574-1581; ISSN NKAKB
- Country of Publication:
- Japan
- Language:
- Japanese
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Related Subjects
*ORGANIC POLYMERS-- CHEMICAL RADIATION EFFECTS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CROSS-LINKING
ELECTRON BEAMS
G VALUE
GAMMA RADIATION
INFRARED SPECTRA
IRRADIATION
MOLECULAR WEIGHT
N40300* --Chemistry--Radiation Chemistry
ORGANIC FLUORINE COMPOUNDS
OXIDATION
OXYGEN
ULTRAVIOLET SPECTRA
VISCOSITY