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Titolo:
Coexistence curves of polystyrene in cyclohexane near the critical double point in composition-pressure space
Autore:
Koizumi, J; Kawashima, Y; Kita, R; Dobashi, T; Hosokawa, H; Nakata, M;
Indirizzi:
Gunma Univ, Fac Engn, Dept Biol & Chem Engn, Kiryu, Gumma 3768515, Japan Gunma Univ Kiryu Gumma Japan 3768515 em Engn, Kiryu, Gumma 3768515, Japan Mitsubishi Rayon Co Ltd, Otake, Hiroshima 7390693, Japan Mitsubishi Rayon Co Ltd Otake Hiroshima Japan 7390693 hima 7390693, Japan Hokkaido Univ, Fac Sci, Dept Polymer Sci, Sapporo, Hokkaido 0600810, JapanHokkaido Univ Sapporo Hokkaido Japan 0600810 oro, Hokkaido 0600810, Japan
Titolo Testata:
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
fascicolo: 8, volume: 69, anno: 2000,
pagine: 2543 - 2548
SICI:
0031-9015(200008)69:8<2543:CCOPIC>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
CRITICAL SOLUTION TEMPERATURES; POLYMER-SOLUTIONS; SYSTEM; METHYLCYCLOHEXANE; EQUILIBRIA; DEPENDENCE; MIXTURES;
Keywords:
critical double point; critical exponent; polymer solution; crossover; composition-pressure spate;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
17
Recensione:
Indirizzi per estratti:
Indirizzo: Dobashi, T Gunma Univ, Fac Engn, Dept Biol & Chem Engn, Kiryu, Gumma 3768515, Japan Gunma Univ Kiryu Gumma Japan 3768515 ryu, Gumma 3768515, Japan
Citazione:
J. Koizumi et al., "Coexistence curves of polystyrene in cyclohexane near the critical double point in composition-pressure space", J PHYS JPN, 69(8), 2000, pp. 2543-2548

Abstract

Phase equilibrium near the critical double point (CDP) was studied in pressure p-temperature T-volume fraction phi space for the system polystyrene(PS) in cyclohexane (CH). The p-T critical lines measured for the molecular weight M-w x 10(-5) = 1.15, 7.19 and 15.6 had a minimum, i.e., CDP at elevated pressures and were used to determine the free energy of the system on the basis of the Flory-Huggins equation. An analysis of the free energy predicted that CDP appeared at atmosphere for M-w = 7.93 x 10(4) and disappearedfor larger molecular weights. For M-w x 10(-4) = 7.5 and 3.7 the coexistence curve in p-phi space were measured by increasing pressure from atmosphere near to 6 MPa and the critical exponent beta(p) for the volume fraction difference phi(+) - phi(-) similar to (p - p(c))(beta P) were determined to be beta(p) = 0.62 +/- 0.03 and 0.39 +/- 0.02, respectively. The farmer value is close to the: doubly enhanced critical exponent at CDP and the latter value is considerably larger than the theoretical value beta = 0.327 at theusual critical point. On light of the molecular weight dependence of beta(p) calculated from the free energy, the observed values of p, was found to reveal the crossover from the usual critical point to CDP.

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Documento generato il 29/03/20 alle ore 14:22:11