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

Abstract

Thermophysical and mechanical properties of two conjugated polymers, poly(p‐phenylene vinylene) (PPV) and polyacetylene (PA), are predicted using molecular dynamics simulations and compared with results obtained from differential scanning calorimetry, nanoindentation, and dynamic mechanical analysis experiments. Glass transition temperature (Tg) is calculated from the changes in the slopes of the specific volume versus temperature and cohesive energy density versus temperature plots, obtained from constant pressure and constant temperature simulations (NPT ensemble). The effects of temperature on the torsion angle distributions and characteristic ratio are analyzed. PPV is found to have a Tg of 416 ± 8 K. PA does not exhibit a glass transition in the temperature range of 120 to 500 K. Using the static deformation method, the values of Young's modulus are calculated to be 1.81 ± 0.34 GPa for PA and 9.20 ± 0.57 GPa for PPV at 298 K. These values are in good agreement with the experimental measurements, validating the suitability of these techniques in the prediction of the polymer properties.

Infrared dichroism studies and anisotropic photoluminescence properties of poly(para-phenylene vinylene) functionalized reduced graphene oxide

“…In this stage of our study, it is worth mentioning that the variation of 28 noted in Table 1 for the IR band peaked at $833-837 cm À1 , assigned to the vibrational modes of phenyl ring C-H out-of-plane bending 18,19 ts well with the PPV torsion angles distribution F 1 and F 2 calculated by R. I. Venkatanarayanan et al 21 to be equal with 27 AE 1 . Comparison with the Table 1S.…”

“…The growth of the q PL value as the RGO weight percentage concentration increases in the composite mass is the result of the p-p* interactions between the phenyl groups of PPV and the RGO sheets and the nonplanarity of PPV MCs. 21 In comparison with composites synthesized by AC of PPV PS in the presence of RGO, the higher values of q PL are reported in the electrochemical synthesized samples as a consequence of the co-generation of PPV in doped state and DSB when additional p-p* interactions between the phenyl groups of DSB and the RGO sheets are invoked. Concerning the adsorption of the lms of PPV/RGO composite, with the same RGO weight percentage concentration on the Au electrode surface, different values of the orientation angle of the transition dipole moment vector for the four IR absorption bands at $837, 963, 1423, and 1514 cm À1 are reported as depending on the synthesis methods of these materials.…”

Molecular simulations of gas transport in hydrogenated nitrile butadiene rubber and ethylene–propylene–diene rubber

“…The glass transition temperatures, T g , of HNBR and EPDM were determined from the plot of specic volume (the reciprocal of density) versus temperature. 24 NPT simulations were performed to determine polymer density over the range of 50 to 500 K at 50 K intervals. Each NPT simulation was performed for 500 ps.…”

“…The glass transition temperature was determined as the temperature at which there was a change of slope in the specic volume versus temperature plot using a segmented regression analysis. 24…”

“…The solubility parameters, d, of HNBR and EPDM were calculated using the van der Waals and coulombic energy of interactions (E vdW and E coul , respectively) and the molar volume, V, which is the ratio of the average molecular weight and the density of the polymer (obtained using the procedure described in Section 2.1). 24 The dispersion and polar components of d were calculated using Scheme 1 The chemical structures of HNBR and EPDM.…”