Thermodynamic miscibility of polystyrene-poly(2,6-dimethyl-1,4-phenylene oxide) blends

• Published in: Canadian journal of chemistry 1985-01, Vol.63 (1), p.223-227
• Main Authors: DiPaola-Baranyi, Giuseppa, Richer, Jocelyn, Prest Jr, William M
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Thermal and thermodynamic properties
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v85-036

Inverse gas chromatography was used to investigate the miscibility behaviour of molten polystyrene-poly(2,6-dimethyl-1,4-phenylene oxide) blends as a function of composition (0, 25, 50, 75, 85, and 100 wt.% PS). Specific retention volumes were measured for various solutes in pure and mixed stationary phases of these polymers at 240 °C. Infinite dilution weight fraction activity coefficients and Flory-Huggins polymer-solute (χ) and polymer-polymer (χ 23 ′) interaction parameters were derived from these data.Negative polymer-polymer interaction parameters were obtained for blends containing more than 60 wt.% PS, suggesting strong intermolecular interactions in the molten state. This is in accord with the well-known compatibility of PS-PPO blends. However, positive χ 23 ′ values were observed for blends containing less than 60 wt.% PS. This suggests weak intermolecular interactions, and perhaps some microheterogeneity in PS-PPO blends with a low PS content. In view of the single, composition dependent T g measured for each of these blends the microheterogeneity or microphase separation must be on a finer scale than that measured by the glass transition.