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(CO 2 + 2‐propanol) mixture as a foaming agent for polystyrene: A simple thermodynamic model for the high pressure VLE‐phase diagrams taking into account the foam vitrification
Author(s) -
Dondero Marco,
Carella José,
Borrajo Julio
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.25658
Subject(s) - polystyrene , thermodynamics , materials science , ternary operation , phase diagram , isopropyl alcohol , phase (matter) , volume (thermodynamics) , polymer , ternary numeral system , triple point , chemical engineering , chemistry , composite material , organic chemistry , physics , computer science , engineering , programming language
The equation of state model developed by Lacombe and Sanchez (J Phys Chem 1976, 80, 2352) is used in the form proposed later by Sanchez and Stone (Polymer Blends, Vol. 1: Formulation, 2000; Chapter 2) to correlate experimental vapor‐liquid equilibrium (VLE) data for the three binaries and the ternary systems. Experimental data from the binary systems carbon dioxide‐isopropyl alcohol (CO 2 ‐IPrOH), isopropyl alcohol‐polystyrene (IPrOH‐PS), and carbon dioxide‐polystyrene (CO 2 ‐PS) are used to calculate VLE properties for the ternary system CO 2 ‐IPrOH‐PS. Two‐dimensional VLE‐phase diagrams were calculated and used to describe from a thermodynamic point of view the pressure, volume, and temperature values that characterize a thermoplastic foam evolution process, from the extruder to the foaming die. For different initial mixture CO 2 + IPrOH concentrations, pressure reduction produces liquid foaming until the vitrification curve arrests the final foam volume expansion. The dependence of the vitreous transition with the system CO 2 + IPrOH concentration while foaming is represented by the Chow (Macromolecules 1980, 13, 362) equation. The calculation procedure is proposed as a design tool to reduce the amount of experimental data usually needed as a requirement previous to the design stage. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2663–2671, 2007