EFFECTS OF GAMMA RADIATION ON POLYMER IN SOLUTION. IV. CROSSLINKING AND DEGRADATION OF POLY(ACRYLIC ACID) IN AQUEOUS SOLUTION

Journal Article · Fri Mar 01 04:00:00 EST 1963 · Bulletin of the Institute for Chemical Research, Kyoto University (Japan)

OSTI ID:4703894

Sakurada, I; Ikada, Y

Dilute aqueous solutions of poly(acrylic acid) in acid form and in sodium-salt form were irradiated with gamma rays from a Co/sup 60/ source both in the presence and in the absence of air. Changes in gelation dose and viscosity were measured. On irradiation in the absence of air, gel formation was observed, and both the gelation dose and the critical concentration for gel-formation increased as the degree of neutralization of polymers increased. The critical concentrations were 0.25, 0.30, 0.56, and 1.0 wt%, for polymers with degrees of neutralization of 0, 5, 10, and 20%, respectively. When NaCl was added to the solution for irradiation so as to diminish the ionization of carboxyl groups, gelation occurred more readily with increasing NaCl concentration, if the NaCl concentration was relatively low. However, as the concentration of NaCl became higher than 0.01N, gel formation was increasingly suppressed with increasing NaCl concentration. This fact demonstrates that there is an optimum expansion of polyion for crosslinking in aqueous solution. On irradiation in the presence of air, the polymer appeared to degrade exclusively. The higher the degree of neutralization, the higher the degree of degradation. If, however, NaCl was present sufficiently in the solution for irradiation, degradation did not occur practically. (auth)

• Research Organization: Kyoto Univ.
• NSA Number: NSA-17-027902
• OSTI ID: 4703894
• Journal Information: Bulletin of the Institute for Chemical Research, Kyoto University (Japan), Journal Name: Bulletin of the Institute for Chemical Research, Kyoto University (Japan) Vol. Vol: 41; ISSN BICRA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACRYLIC ACID
AIR
COBALT 60
CROSS-LINKING
DECOMPOSITION
GAMMA SOURCES
IRRADIATION
METALS, CERAMICS, AND OTHER MATERIALS
POLYMERIZATION
POLYMERS
QUANTITY RATIO
RADIATION EFFECTS
SODIUM CHLORIDES
SODIUM COMPOUNDS
SOLUTIONS
VISCOSITY