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Ultrasonic wave attenuation during water sorption in poly(2‐hydroxyethyl methacrylate) hydrogels
Author(s) -
Maffezzoli A.,
Luprano V. A.,
Montagna G.,
Esposito F.,
Nicolais L.
Publication year - 1996
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.10578
Subject(s) - materials science , attenuation , sorption , penetrant (biochemical) , self healing hydrogels , scattering , acoustic attenuation , polymer , reflection (computer programming) , composite material , methacrylate , absorption (acoustics) , ultrasonic sensor , acoustic microscopy , polymer chemistry , optics , microscopy , acoustics , copolymer , organic chemistry , chemistry , physics , adsorption , computer science , programming language
A scanning laser acoustic microscope (SLAM) was used to measure the acoustic attenuation during water sorption in a film of crosslinked poly(2‐hydroxyethyl methacrylate) [poly(HEMA)] hydrogel. The contribution of reflection, scattering, and absorption of acoustic waves to the measured attenuation is evaluated. The analysis of a model accounting only for the possible reflection of the acoustic waves at the swollen/unswollen boundaries indicates that the time dependence of the attenuation during water sorption cannot be explained simply by accounting for the presence of two additional interfaces. A predominant contribution of acoustic wave absorption during the glass transition, occurring at the two swollen/unswollen interfaces, is assumed. Also, microvoids cannot be excluded as contributors to craze growth in the glassy matrix at the penetrant/polymer interface.