Zero and Off-Zero Critical Concentrations in Systems Containing Polydisperse Polymers † with Very High Molar Masses. 2. The System Water−Poly(vinyl methyl ether)

• Published in: Macromolecules Vol. 30; no. 3; pp. 410 - 416
• Main Authors: Schäfer-Soenen, H, Moerkerke, R, Berghmans, H, Koningsveld, R, Dušek, K, Šolc, K
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 10.02.1997
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Solution and gel properties; Polydispersed polymer; Aqueous solution; Experimental study; Phase diagram; Methyl vinyl ether polymer; Binary system
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma960114o

Cloud-point curves by DSC measurements at different scanning rates on solutions of two samples of poly(vinyl methyl ether) in water show two minima in a temperature−composition plot. The significance of the data was confirmed by static measurements of the coexisting-phase compositions and phase-volume ratios. A thermodynamic analysis in terms of a strongly concentration-dependent interaction parameter leads to the conclusion that the system H2O/PVME exhibits so-called type III behavior. For polymers of infinite molar mass, such behavior is characterized by the occurrence of two off-zero critical concentrations, in addition to the usual zero critical concentration marking the ϑ state.