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Molecular weight and concentration dependence of the thermal conductivity of polystyrene in benzene

The thermal conductivities of polystyrene in benzene solutions at concentrations of 0.l to 15 weight percent were measured at 25° C and atmospheric pressure. Osmotic pressure measurements and information supplied by the manufacturer indicated number average molecular weights (M̅<sub>N</sub>) of 21,000, 264,000, and 660,000 for the three polystyrene polymers studied. The following equation was obtained by regression analysis of the results and predicts the measured thermal conductivity within ± 2 percent in the range of variables studied.

K = 0.1088 - 0.1311 C + 0.57629 C² - 6.40 x 10⁻⁵ (M̅<sub>N</sub> x 10⁻⁵)² - 4.2 x 10⁻³ C(M̅<sub>N</sub> x 10⁻⁵)
where: K = thermal conductivity of solution, Btu/hr-ft-°F
C = weight fraction polymer
M̅<sub>N</sub> = number average molecular weight

The conductivities were measured in a steady-state concentric cylinder apparatus developed for measuring the thermal conductivity of viscous liquids. The annular gap was 0.052 inches and guard heaters were employed to minimize end losses and distortion of the steady-state temperature distribution at the ends. The apparatus was calibrated with three liquids of known thermal conductivity, water, cyclohexanol and ethylene glycol. The calibration factor was found to be constant to within experimental error (± 3 percent) over the range of measurements. / Master of Science

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/71014
Date January 1968
CreatorsEpps, Lionel Bailey
ContributorsChemical Engineering
PublisherVirginia Polytechnic Institute
Source SetsVirginia Tech Theses and Dissertation
Languageen_US
Detected LanguageEnglish
TypeThesis, Text
Formatvii, 169 leaves, application/pdf, application/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/
RelationOCLC# 9249617

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