ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The effects of solvent size, temperature, and polymer molecular weight on the swelling of poly(methyl methacrylate) (PMMA) thin films in low molecular weight alcohols were investigated using an in situ ellipsometer. Apparent activation energies were indicative of non-Fickian diffusion, although optical data showed substantial Fickian character for swelling in methanol and moderate Fickian character in ethanol. Penetration rates were strongly dependent on the solvent molar volume for methanol, ethanol, and isopropanol, but 1-butanol and 2-pentanol had rates similar to isopropanol. The effective cross sections of these longer molecules are similar to isopropanol, and this apparently explains the similar penetration rates. The effect of polymer molecular weight (MW) on methanol penetration rates (21-27°C) was investigated with monodisperse PMMA (Mn = 6.4-40.0 × 104 g/mol). A minimum at intermediate MW was observed. Isopropanol swelling rates (45-52°C) were insensitive to MW. The swelling data were also used to determine parameters for transport models that describe the swelling of thin polymer films.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1990.070390404
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