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Dissolution and mutual diffusion of poly( N ‐vinyl pyrrolidone) in short‐chain poly(ethylene glycol) as observed by optical wedge microinterferometry
Author(s) -
Bairamov D. F.,
Chalykh A. E.,
Feldstein M. M.,
Siegel R. A.,
Platé N. A.
Publication year - 2002
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.10635
Subject(s) - ethylene glycol , diffusion , peg ratio , polymer chemistry , materials science , activation energy , polymer , arrhenius equation , glass transition , dissolution , optical microscope , polyvinyl alcohol , chemical engineering , analytical chemistry (journal) , chemistry , composite material , thermodynamics , scanning electron microscope , organic chemistry , physics , finance , engineering , economics
Dissolution and mutual diffusion of poly( N ‐vinylpyrrolidone) (PVP) in short‐chain poly(ethylene glycol) PEG400 were studied by wedge microinterferometry over the temperature range of 40–100°C. Successive photographs of interference patterns measured at λ = 546 nm with an optical microscope at 130× magnification were used to determine the PVP/PEG concentration–distance profiles. These profiles were found to be highly asymmetric, exhibiting steep concentration gradients near the surface of the glassy polymer sample. The PVP/PEG system is completely miscible, and interdiffusion kinetics are Fickian with a concentration‐dependent mutual diffusion coefficient, D V . Thermal activation of diffusion was studied in terms of an Arrhenius‐type relation, with concentration dependent activation energy E a . Values of D V and E a are in accord with the compositional behavior of the glass transition temperature in PVP–PEG blends, indicating that PVP plasticized with PEG behaves like an elastomer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1128–1136, 2002