IRRADIATION OF POLYETHYLENE OXIDE AND POLYPROPYLENE

Journal Article · Sat Jun 01 04:00:00 EDT 1963 · J. Polymer Sci., Pt. A

DOI:https://doi.org/10.1002/pol.1963.100010634· OSTI ID:4695977

Salovey, R; Dammont, F R

The solubility behavior of electron-irradiated (in vacuo) polyethylene oxide indicates a ratio of main-chain scission density to the density of crosslinked units of 0.6, independent of molecular weight. This value, derived from measurements at high doses, correlates well with the observed increase in intrinsic viscosity and invariance of numberaverage molecular weight at low irradiation doses. Analogous measurements on polypropylene indicate a linear dependence of S + S/sup 1/2/ (where S is the sol fraction of the irradiated polymer) on the reciprocal irradiation dose. This treatment leads to a ratio of scission-to-crosslinking of 0.8. Increased scission in polypropylene as compared to polyethylene oxide is evidenced by a gradual decrease in the intrinsic viscosity as a function of dose. This decrease is not indicative of an initial irradiation degradation of the polymer, because the number-average molecular weight is relatively unaffected by irradiation until quite close to the gel point. The intrinsic viscosity of the progressively crosslinked polymer is apparently depressed by branching, Direct comparison of the results on polypropylene with theory is uncertain because of a nonrandom initial molecular weight distribution. It is reemphasized that the intrinsic viscosity is not a simple indication of molecular weight changes in crosslinking polymers. (auth)

• Research Organization: Bell Telephone Labs., Inc., Murray Hill, N.J.
• NSA Number: NSA-17-027914
• OSTI ID: 4695977
• Journal Information: J. Polymer Sci., Pt. A, Journal Name: J. Polymer Sci., Pt. A Vol. Vol: 1
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CROSS-LINKING
DECOMPOSITION
DENSITY
DISTRIBUTION
ELECTRONS
IRRADIATION
METALS, CERAMICS, AND OTHER MATERIALS
MOLECULES
OXIDES
POLYETHYLENES
POLYMERIZATION
POLYMERS
POLYPROPYLENE
PROPYLENE
RADIATION DOSES
RADIATION EFFECTS
VISCOSITY
WEIGHT