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Vapor and liquid equilibria in glassy polyblends of polystyrene and poly(2,6‐dimethyl‐1,4‐phenylene oxide) Part I
Author(s) -
Jacques C. H. M.,
Hopfenberg H. B.
Publication year - 1974
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.760140607
Subject(s) - materials science , penetrant (biochemical) , polystyrene , sorption , glass transition , phenylene , differential scanning calorimetry , polymer , oxide , polymer chemistry , chemical engineering , polymer blend , hexane , composite material , thermodynamics , organic chemistry , copolymer , chemistry , physics , adsorption , engineering , metallurgy
The equilibrium sorption of n‐hexane vapor and n‐hexane liquid in solution cast films of polystyrene, poly(phenylene oxide), and blends of these homopolymers was studied over a significant range of penetrant activity and temperature. These equilibrium sorption measurements were supplemented by density determinations, refractive index measurements, differential scanning calorimetry and differential thermal analysis. A seemingly complicated pattern of results emerged when the equilibrium penetrant content was plotted as a function of blend composition. At relatively low activity and temperature the equilibrium concentration of n‐hexane in these films monotonically increased with poly(phenylene oxide) content in the blend. Conversely, at high activities and in unit activity liquid, the equilibrium penetrant concentration exhibited a distinct minimum when plotted as a function of blend composition. At higher activities, solvent induced crazing accompanied the sorption of penetrant. These results were explained consistently by considering the nature of the sorption isotherm over an activity range sufficient to lower the glass transition temperature, of the equilibrated and swollen blend, below the temperature of the sorption experiment. Most importantly, the interpretation and explanation of these data are based upon phenomena common to all glassy polymer‐organic penetrant systems and no special properties of this blend system were included in the analysis. The results, therefore, reflect the apparent homogeneity of polystyrene‐poly (phenylene oxide) blends and are useful in considering the equilibrium of penetrant sorption in glassy polymers as a general class of materials.