Avtor/Urednik		Kirinčič, Stanislava
Naslov		Transportne lastnosti vodnih raztopin polietilenglikola
Prevedeni naslov		Transport properties of aqueous solutions of poly(ethylene glycol)
Tip		monografija
Kraj izdaje		Ljubljana
Založnik		Biotehniška fakulteta
Leto izdaje		1996
Obseg		str. 76
Jezik		slo
Abstrakt		The densities and viscosities of aqueous solutions of poly(ethylene glycol)s with nominal molecular weights ranging from 300 to 350000 g mol-1 were determined up to concentration of 0.5 or 0.3 g cm-3 respectively, at 298.15 K. From density dta the apparent specific volume of solute and the partial specific volume of solute and solvent were calculated. The specific excess volume of the solutions and the coefficients of the virial expansion of the excess property were evaluated and interpreted in terms of solute-solute and solute-solvent interactions. The partial molar volume of the repeating unit, as well as the excluded volume between the solvent molecules and repeating unit, and the excess excluded volume were evaluated. From these results may be concluded that the systems behave rather non-ideally, that the solvation process as well as the structural changes of the solvent depend primarily on the average molecular weight of the solute and that the effect of the end groups on the molecular weight dependence of volumetric properties is negligible. From viscosity data the intrinsic viscosity was calculated which gradually increases with molecular weight of solute. The viscosity average molecular weight of solute is sistematically higher than the nominal average molecular weight, what could be attributed mostly to the polydisperse nature of poly(ethylene glycol). The viscosity coefficient B was determined and it depends on the average molecular weight of solute. This could be ascribed to the change of the conformation of poly(ethylene glucol) molecule, which is hydrated through hydrogen bonding. From the difference between the partial molar Gibbs free energy of activation for viscous flow of the solute at infinite dilution and of respective molar quantity of pure water, it may be anticipated, that in the systems studied the solute-solvent bonds are stronger than the solvent-solvent bonds in the transition state. (Abstract truncated at 2000 characters.)
Deskriptorji		POLYETHYLENE GLYCOLS SOLUTIONS VISCOSITY TEMPERATURE MOLECULAR WEIGHT WATER