Prediction of Solubility of α-Olefins in Polyolefins Using a Combined Equation of StateMolecular Dynamics Approach

Abstract

In the present study, the Sanchez−Lacombe equation of state (i.e., SL EOS) was employed to calculate the solubilities of α-olefins in polyolefins over a wide range of pressures and temperatures. The characteristic parameters (i.e., P*, T*, and ρ*) of the pure components, appearing in the Sanchez−Lacombe EOS, were estimated using a molecular dynamic procedure (MD). For all binary systems examined, a single binary parameter, k ij , accounting for the interactions between the penetrant molecules and the polymer chains was used to fit model predictions to available solubility measurements. The value of the binary interaction parameter was found to depend on the type of the penetrant molecules, the comonomer type in the ethylene copolymers, and the polymer crystallinity as well as the selected experimental conditions (i.e., temperature and pressure). The theoretically calculated solubilities were found to be in excellent agreement with the corresponding experimentally measured values, demonstrating the capability of the SL EOS to predict the solubility of α-olefins in semicrystalline polyolefins.

Optimal Catalyst and Cocatalyst Precontacting in Industrial Ethylene Copolymerization Processes

“…Therefore, the variation of the particle radius,̇( ) = ( ( )/ ), caused by solid particle swelling, is not considered in (1) [26,27]. Moreover, the degree of swelling caused by the sorption of triethylaluminum in the catalyst solid phase was estimated by employing a fundamental thermodynamic model (i.e., Sanchez Lacombe EOS) and it was found to be below 5% in terms of catalyst particle volume change [32,33].…”

A Survey of Equations of State for Polymers

“…Kanellopoulos et al [97] used the SL equation to calculate the solubility of α-olefins in polyolefins over a wide range of temperatures and pressures. The characteristic parameters of the pure components (T*, P*, ρ*) were estimated using a dynamic molecular procedure: using commercial software, each selected species (i.e.…”

Calculation of the solubility of liquid solutes in glassy polymers

“…33 Water Sorption in PSf. For the solubility of water in bisphenol-A PSf, detailed experimental data were reported at 40 C by Schult and Paul 54 who used the product commercially available as Udel 1700, without indicating explicitly the pure polymer density; however, the latter value can be obtained from the manufacturer data sheet 55 as 1.24 g/cm 3 at ambient temperature, changing with temperature with a volume thermal expansion coefficient of 56 Â 10 À6 K…”

“…38 The latter approaches and the multiscale methods developed 39,40 appear very promising, even though at present their application for the routine calculation of solubility isotherms appears too long and costly to be applied as the only standard tool for general use.…”

“…, so that the density at 40 C can be estimated as 1.236 g/cm 3 . Using that value, the experimental data for the vapor solubility isotherm can be well described by the NELF model with no need of a swelling coefficient (k sw ¼ 0), consistently with the rather limited solubility.…”