Application of the van der Waals equation of state to polymers IV. Correlation and prediction of lower critical solution temperatures for polymer solutions

Saraiva, A; Kontogeorgis, GM; Harismiadis, VI; Fredenslund, A; Tassios, DP

dc.contributor.author	Saraiva, A	en
dc.contributor.author	Kontogeorgis, GM	en
dc.contributor.author	Harismiadis, VI	en
dc.contributor.author	Fredenslund, A	en
dc.contributor.author	Tassios, DP	en
dc.date.accessioned	2014-03-01T01:11:44Z
dc.date.available	2014-03-01T01:11:44Z
dc.date.issued	1996	en
dc.identifier.issn	0378-3812	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/11791
dc.subject	Application	en
dc.subject	Cubic	en
dc.subject	Equation of state	en
dc.subject	Liquid-liquid equilibria	en
dc.subject	Lower critical solution temperature	en
dc.subject	Method of calculation	en
dc.subject	Polymer solutions	en
dc.subject	Theory	en
dc.subject.classification	Thermodynamics	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.other	Binary mixtures	en
dc.subject.other	Calculations	en
dc.subject.other	Mixing	en
dc.subject.other	Molecular dynamics	en
dc.subject.other	Phase diagrams	en
dc.subject.other	Phase equilibria	en
dc.subject.other	Phase separation	en
dc.subject.other	Polymers	en
dc.subject.other	Solutions	en
dc.subject.other	Solvents	en
dc.subject.other	Statistical methods	en
dc.subject.other	Temperature	en
dc.subject.other	Arithmetic means	en
dc.subject.other	Athermal polymer solution	en
dc.subject.other	Bethelot combining rule	en
dc.subject.other	Energy parameter	en
dc.subject.other	Free volume activity coefficient models	en
dc.subject.other	Soave method	en
dc.subject.other	van der Waals equation of state	en
dc.subject.other	Equations of state	en
dc.title	Application of the van der Waals equation of state to polymers IV. Correlation and prediction of lower critical solution temperatures for polymer solutions	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/0378-3812(95)02834-X	en
heal.identifier.secondary	http://dx.doi.org/10.1016/0378-3812(95)02834-X	en
heal.language	English	en
heal.publicationDate	1996	en
heal.abstract	The van der Waals equation of state is used for the correlation and the prediction of the lower critical solution behavior or mixtures including a solvent and a polymer. The equation of state parameters for the polymer are estimated from experimental volumetric data at low pressures. The equation of state parameters for the solvent are estimated via the classical Soave method, i.e. using the critical properties and a generalized equation for the energy parameter. When extended to mixtures, the van der Waals one-fluid mixing rules along with the Berthelot combining rule for the molecular cross energy parameter are used. The arithmetic mean combining rule is used for the cross co-volume parameter. The deviations from the Berthelot combining rule are taken into account via a simple expression which has been previously obtained from vapor-liquid equilibrium data of athermal polymer solutions and has been successfully used for the prediction of upper critical solution temperatures for various binary polymer solutions. In this work, we demonstrate and explain some of the problems which cubic equations of state exhibit in describing the lower critical solution behavior for polymer solutions. These problems are overcome by using a temperature-dependent interaction parameter, even for small temperature ranges, leading to excellent results. Despite the problems, we have developed an empirical methodology in using the van der Waals equation of state with a single interaction parameter for predicting the lower critical solution behavior of polymer/solvent solutions. The results are satisfactory. typically, the difference between the predicted and the experimental lower critical solution temperatures is between 10 and 35 degrees C.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Fluid Phase Equilibria	en
dc.identifier.doi	10.1016/0378-3812(95)02834-X	en
dc.identifier.isi	ISI:A1996UB58200005	en
dc.identifier.volume	115	en
dc.identifier.issue	1-2	en
dc.identifier.spage	73	en
dc.identifier.epage	93	en