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Spin probe studies of nonsolvent penetration into polymer particle formed from poly(vinyl acetate) and poly(2‐ethylhexyl methacrylate)
Author(s) -
Pekcan Önder,
Demir Yusuf
Publication year - 1993
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.1993.070491102
Subject(s) - vinyl alcohol , vinyl acetate , methacrylate , polymer chemistry , solvent , polymer , rotational diffusion , analytical chemistry (journal) , hildebrand solubility parameter , particle (ecology) , materials science , colloid , methyl methacrylate , chemistry , molecule , solubility , copolymer , organic chemistry , oceanography , geology
Nonaqueous dispersion (NAD) of poly(vinyl acetate) (PVA c ) particles sterically stabilized by poly(2‐ethylhexyl methacrylate) were examined by ESR spectroscopy after introduction of a trace quantity of a spin probe, 3‐carbomoyl‐2,2,5,5‐tetramethyl 3‐pyrolin‐1‐yloxy. ESR spectra were monitored as a function of temperature from ‐160 to 100°C. In spite of the complex morphology of the particle, it is found that the behavior of the probe in the NAD was essentially identical to that in a pure PVA c matrix. Solvent penetration into (NAD) particles were studied. These colloidal particles were exposed to a dilute solution of the spin probe, and the bimodal distribution of the ESR spectra of this probe molecule were carefully monitored as a function of time. Fickian‐type diffusion of spin probes into the particles was observed and a spherical model was employed to obtain the diffusion coefficients ( D ) in various solvents. D values were found around 10 –15 cm 2 /s and were interpreted as the parameter, inversely proportional to the apparent viscosity of the environment inside the PVA c particle. The maximum amount of diffused solvent molecules ( M ∞ ) into the PVA c particle was found inversely proportional to polymer‐solvent interaction through the solubility parameters. © 1993 John Wiley & Sons, Inc.