Alena Randová

Low-density polyethylene in mixtures of hexane and benzene derivates

Preferential sorption, equilibrium swelling degree, and volume of the swollen membrane in systems low-density polyethylene + hexane + aromatic compound (benzene, methylbenzene, or ethylbenzene) were studied using gravimetric and dilatometric methods at the temperature of 25 °C. Aromatic compounds are preferentially sorbed in low-density polyethylene compared to hexane. Experimental volume changes of the membrane were found to be noticeably different from those calculated on the basis of mass sorption data under the assumption of additivity. This difference points to the existence of the interactions between the polymer and the surrounding liquid mixture. The volume swelling degree curves are close to each other in the whole concentration range of the binary liquid mixture (hexane + aromatics) suggesting that the attractive forces between the polymer chains are the deciding factor limiting the volume expansion of the membrane in all three systems to the same extent.

Group Contribution Methods for Estimation of Selected Physico-Chemical Properties of Organic Compounds

© 2012 Kolska et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Group Contribution Methods for Estimation of Selected Physico-Chemical Properties of Organic Compounds

Diffusion coefficients in systems LDPE+cyclohexane and LDPE+benzene

Abstract The swelling of the low density polyethylene in organic liquids (cyclohexane and benzene) was studied. The area of swelling was measured as a function of temperature and time. The experimental data were used for calculating the diffusion coefficients and the activation energies of this process.

Fundamentals and Measurement Techniques for Solvent Transport in Polymers

The immersion of the polymeric membrane into a low-molecular-weight liquid medium involves several processes like sorption of liquid molecules into the polymer and the dimensional changes of the membrane caused by mutual interactions between the surrounding liquid and polymer matrix (swelling). The quantitative assessment of liquid sorption can be performed by monitoring the mass changes of the membrane during its soaking in the liquid (sorption techniques); by the desorption techniques, i.e., the monitoring of the swollen membrane mass taken out of the liquid; or by the volumetric techniques consisting of monitoring the dimensional changes of the membrane sample.

Cyclopentyl methyl ether, tert -amyl methyl ether and tert -butyl methyl ether: density, dynamic viscosity, surface tension and refractive index

This work presents densities, dynamic viscosities, surface tensions, and refractive indices of three methyl ethereal solvents: cyclopentyl methyl ether (CPME), tert-amyl methyl ether (TAME), and tert-butyl methyl ether (MTBE). CPME and TAME were chosen as methyl alternatives of the common but environmentally problematic MTBE. The highest density, viscosity, surface tension, and refractive index were observed for CPME and the lowest for MTBE. The results are in good agreement with other authors’ data. Based on the experiments, the critical temperature and the critical pressure of CPME were estimated. The parachor, molar refraction, and critical compressibility factor were calculated from experimental data. Parameterisations of the experimental data using corresponding correlative models are presented.Graphical abstract