ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
An osmometer is described which is applicable to highly viscous concentrated polymer solutions. Results are presented for polyisobutylene (MW = 90,000) in cyclohexane at 30 and at 8°, and in benzene at 24.5° (the theta point) and at 50°. Concentrations ranging up to 20% (w/v) and 29%, respectively, were used. The results are compared with the semiempirical formulation of the chemical potential: \documentclass{article}\pagestyle{empty}\begin{document}$$ {{\left( {\mu _1 - \mu _1^0 } \right)} \mathord{\left/ {\vphantom {{\left( {\mu _1 - \mu _1^0 } \right)} {RT}}} \right. \kern-\nulldelimiterspace} {RT}} = \ln \left( {1 - v_2 } \right) + \left( {{{1 - 1} \mathord{\left/ {\vphantom {{1 - 1} x}} \right. \kern-\nulldelimiterspace} x}} \right)v_2 + \chi _1 v_2^2 + \chi _2 v_2^3 + \ldots $$\end{document} In cyclohexane χ1 = 0.429 at 30°, and 0.434 at 8°; higher parameters may be neglected. These observations stand in excellent agreement with results of vapor pressure measurements on more concentrated solutions, with parameters derived from intrinsic viscosities, and with the second virial coefficient observed at higher dilutions. The results in benzene at 24.5° lead to χ1 = 0.500 and x2 = 0.31; at 50°, χ1 = 0.485 and x2 = 0.29. The values of χ1 are compared with deductions from instrinsic viscosities and from second virial coefficients. The fact that the critical miscibility point for M = ∞ occurs at v2 = 0 for this system requires x2 〈 1/3.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1957.1202511104
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