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Acoustic relaxation and infrared spectroscopic measurements of the plasticization of poly(methyl methacrylate) by water
Author(s) -
Gilbert A. S.,
Pethrick R. A.,
Phillips D. W.
Publication year - 1977
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1977.070210202
Subject(s) - methyl methacrylate , poly(methyl methacrylate) , plasticizer , materials science , glass transition , methacrylate , polymer , atmospheric temperature range , relaxation (psychology) , activation energy , analytical chemistry (journal) , infrared spectroscopy , diffusion , attenuation coefficient , attenuation , polymer chemistry , infrared , composite material , chemistry , thermodynamics , organic chemistry , optics , copolymer , psychology , social psychology , physics
Measurements are reported on the acoustic attenuation and velocity of dry and wet samples of poly(methyl methacrylate) over a temperature range of 5° to 70°C and over a frequency range of 5 to 35 MHz. Lowering of the glass transition temperature with increase in water content was reflected in an increase in the acoustic attenuation and a lowering of the velocity at high temperature. Comparison of the infrared spectra of wet and dry thin films indicates that water exhibits spectroscopic characteristics of isolated rather than highly clustered molecules. A study of the temperature dependence of the diffusion coefficient of water into the polymer matrix provided an activation energy for the migration process. The data suggest that water plasticizes poly(methyl methacrylate) via specific local interactions with the backbone.