Molecular modeling of temperature dependence of solubility parameters for amorphous polymers

Abstract

A molecular modeling strategy is proposed to describe the temperature (T) dependence of solubility parameter (δ) for the amorphous polymers which exhibit glass-rubber transition behavior. The commercial forcefield “COMPASS” is used to support the atomistic simulations of the polymer. The temperature dependence behavior of δ for the polymer is modeled by running molecular dynamics (MD) simulation at temperatures ranging from 250 up to 650 K. Comparing the MD predicted δ value at 298 K and the glass transition temperature (Tg) of the polymer determined from δ–T curve with the experimental value confirm the accuracy of our method. The MD modeled relationship between δ and T agrees well with the previous theoretical works. We also observe the specific volume (v), cohesive energy (Ucoh), cohesive energy density (ECED) and δ shows a similar temperature dependence characteristics and a drastic change around the Tg. Meanwhile, the applications of δ and its temperature dependence property are addressed and discussed.

Simulated Dilatometry and Static Deformation Prediction of Glass Transition and Mechanical Properties of Polyacetylene and Poly(para‐phenylene vinylene)

“…In the case of PPV, both CED and δ showed a discontinuity at around 142 °C, the glass transition temperature determined from the specific volume versus temperature plot. A similar change in cohesive energy density near T g has been previously reported for emeraldine‐based polyaniline . Polyacetylene did not show a “kink” (a discontinuous change in the first derivative) in the CED versus T or δ versus T plots.…”

“…A similar change in cohesive energy density near T g has been previously reported for emeraldine-based polyaniline. [ 43 ] Polyacetylene did not show a "kink" (a discontinuous change in the fi rst derivative) in the CED versus T or δ versus T plots.…”

“…Cohesive energy density (CED), which is the cohesive energy per unit volume of the material, is related to the molar enthalpy of vaporization, Δ H vap and molar volume, V by…”

Effect of entanglements in the microstructure of cured NR/SBR blends prepared by solution and mixing in a two-roll mill

“…Thermodynamically, the miscibility in polymer-solvent mixtures or polymer-polymer blends can be predicted if the values of the Hildebrand solubility parameters, d, of their components are similar [34][35][36]. At room temperature, the solubility values of NR, SBR and toluene are: d NR = 16.6 MPa 1/2 , d SBR = 17.3 MPa 1/2 and d toluene = 18.3 MPa 1/2 , respectively [37].…”

Binding affinity between small molecules in solvent and polymer film using molecular dynamics simulations

“…With an appropriate interaction potential, MD simulations can predict many thermodynamics and transport properties of small molecules in a polymeric film such as the solubility parameter [13][14][15], the partition coefficient [16,17] and the diffusion coefficient [18][19][20]. In MD simulations, the prediction of binding affinity between two components is characterized through the solubility parameter ı.…”