Diffusion of radioactively tagged penetrants through rubbery polymers. I. Penetrants with very low solubility. [/sup 14/C]
The diffusion of radioactively tagged n-hexadecane, 1,7-heptanediol, and ethylene glycol has been studied in one polar and six nonpolar rubbery polymers. The penetrant-polymer pairs included some in which the two components were miscible in all proportions and some in which they were nearly incompatible (solubility of penetrant in polymer of the order of 1 percent). The theory for the thin smear method for measuring the diffusion coefficient was evaluated for incompatible pairs with two cases: case 2, when the rate-limiting step is diffusion through the polymer; and case 3, when the rate-limiting step is entry into the polymer across the penetrant-polymer interface. They are easily distinguished experimentally from each other and from case 1, which refers to completely miscible pairs. The diffusion coefficients, when compared in four hydrocarbon rubbers, of n-hexadecane and 1,7-heptanediol were similar in magnitude even though in each rubber the hexadecane was soluble in all proportions and the diol only very slightly. The diffusion coefficient of ethylene glycol, despite its extreme thermodynamic incompatibility, appeared to be somewhat larger than those of the other penetrants.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 7311396
- Journal Information:
- J. Appl. Polym. Sci.; (United States), Vol. 21:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
GLYCOLS
DIFFUSION
HEXADECANE
RUBBERS
PERMEABILITY
CARBON 14 COMPOUNDS
LABELLED COMPOUNDS
MEASURING METHODS
MEDIUM TEMPERATURE
SOLUBILITY
ALCOHOLS
ALKANES
ELASTOMERS
HYDROCARBONS
HYDROXY COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
POLYMERS
360404* - Materials- Polymers & Plastics- Physical Properties- (-1987)
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)