High-Pressure Dynamic Light Scattering of Poly(ethylene-co-1-butene) in Ethane, Propane, Butane, and Pentane at 130 °C and Kilobar Pressures

Autor:	Dan Li, Mark A. McHugh, John H. van Zanten, Ozge Guney-Altay, Thomas Kermis, Il-Hyun Park
Rok vydání:	2004
Předmět:	Alkane chemistry.chemical_classification Phase boundary Polymers and Plastics Chemistry Organic Chemistry Analytical chemistry Butane Inorganic Chemistry Pentane chemistry.chemical_compound Higher alkanes Virial coefficient Propane Polymer chemistry Materials Chemistry Bar (unit)
Zdroj:	Macromolecules. 37:9123-9131
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma0487103
Popis:	Poly(ethylene-co-1-butene) diffusion in ethane, propane, butane, and pentane indicates that ethane solutions are remarkably different. For propane, butane, and pentane the dynamic second virial coefficient, kD, is negative near the phase boundary, increases rapidly to positive values within ∼100 to 200 bar of the respective phase boundary, and approaches a constant value at high pressures. For ethane, kD is also negative near the phase boundary; it increases at a slower rate and becomes only slightly greater than zero. kD for all four solvents superpose when plotted against “methyl” molar density, suggesting thermodynamic interactions rather than hydrodynamic forces dominate. For propane, butane, and pentane the hydrodynamic radius, RH, also starts at a low value near the phase boundary and increases to the same value for all three alkanes. For ethane RH is ∼30% smaller than those for the higher alkanes, reflecting the poor quality of ethane even 1000 bar above the phase boundary.
Databáze:	OpenAIRE
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