Experimental verification on upper critical solution temperature (UCST) behavior in blend of poly(2,6-dimethyl p-phenylene oxide) with poly(4-methyl styrene)

• Published in: Polymer (Guilford) Vol. 43; no. 15; pp. 4225 - 4230
• Main Authors: Woo, E.M, Cho, I.-C, Lee, L.-T
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2002; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Poly( p-methyl styrene); Poly(2,6-dimethyl phenylene oxide); Poly(4-methyl styrene); Properties and characterization; Thermal and thermodynamic properties; Poly(4-methyl styrene); Poly(2,6-dimethyl phenylene oxide); Poly( p-methyl styrene); Polymer blends; Styrene(methyl) polymer; Phase diagram; Morphology; Thermodynamic properties; Experimental study; Phenylene oxide(dimethyl) polymer
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/S0032-3861(02)00219-7

Rare upper critical solution temperature (UCST) behavior was found and experimentally demonstrated in the blend comprising poly(2,6-dimethyl p-phenylene oxide) with poly(4-methyl styrene) (PPO/P4MS). Complexity of phase behavior in the PPO/P4MS system has caused puzzling analyses in the past years. This study re-investigated and clarified past mis-interpretations related to this interesting blend system. This study concluded that the PPO/P4MS blend is an immiscible system at ambient, which, however, turns into a miscible phase with UCST behavior at higher temperatures. With the finding of UCST in the PPO/P4MS blend, a critical contribution of this work was to resolve the conflicting arguments that have gone on for a long time in determination and interpretation of the thermodynamic phase behavior of PPO/P4MS. Phase behavior with UCST in the PPO/P4MS blend system and its interpretation were supported with clear experimental evidence.