Prediction and estimation of solvent diffusivities in polyacrylate and polymethacrylates

Abstract

The relationship between polymer side-chain length and the hole free volume that is effective for solvent diffusion was investigated for polyacrylates and polymethacrylates on the basis of free-volume theory. Measurements of a polymer's viscoelasticity and solvent diffusivity provided experimental evidence for polymer segment mobility, and the results indicated that hole free volume in a linear polymer increases with hydrocarbon side-chain length. Because the molecular mechanisms of polymer viscoelasticity and diffusivity are identical, the free-volume parameters obtained for polyacrylates and polymethacrylates by measuring the polymer viscoelastic-temperature dependence can reliably be used in predicting the solvent diffusion coefficient.

Prediction of Solvent Diffusivities in Amorphous Polymers by Free-Volume Theory: Group Contribution and PALS Methods

“…6,9 In the Vrentas-Duda model, Sugden's method was used. [6][7][8][9][10][11][12][13] Here, we employ Bondi's group contribution treatment, in whichṼ V o ð0Þ can be well approximated by 1:3Ṽ V W . 21,24 The factor of 1.3, which is assumed to be a universal constant effective for all groups and …”

“…[6][7][8][9][11][12][13] Modification of Free-Volume Theory Based on Group Contribution Hole Free Volume of Polymer. According to the free-volume theory, the hole free volume of polymer is regarded as an alternate portion in the Williams-Landel-Ferry (WLF) theory.…”

“…While much work developed approaches from viscoelastic data, [6][7][8][9][10][11][12][13] or EOSs, [16][17][18] the characteristic parameters of which have to be obtained from pressure-volume-temperature (PVT) data for polymers inspected. The amount of such available experimental data is insufficient, especially for polymers containing non-hydrogen atoms, rings or double bonds, or novel polymeric structures which have not yet been synthesized at present.…”

“…Unfortunately, in order to quantify the free volume provided by polymer, many efforts have been given by fitting experimental results from polymer viscoelasticity, meaning a great deal of time and cost consumption. [6][7][8][9][11][12][13] In our previous work, theoretical equations-ofstate (EOSs) (i.e., hole theory and lattice-fluid theory) were employed to determine the free volume of polymer, and measurements of viscoelasticity can be avoided. [16][17][18] These EOSs have a statistical-mechanical nature and a reduced dimensionless form to describe volumetric properties for polymer liquids.…”

“…Over the past decades, an extensive amount of work has been devoted to the development of theoretical models that exhibit good correlations of solvent diffusion coefficient in polymer solutions. 1 The most successful models are based on the concept of free volume, [2][3][4][5][6][7][8][9][10][11][12][13] which is defined as the unoccupied volume surrounding the hard core volume of matter, as well known in polymer science. This concept was first proposed by Cohen and Turnbull for the case of molecular diffusion in liquid systems, 14,15 introduced by Fujita for the description of migration in polymer-solvent mixtures, 2,5 and extensively investigated by Vrentas and Duda for both self-and mutualdiffusion in polymer-solvent systems.…”