Interaction parameter (chi); expansion factor (epsilon); steric hindrance factor (sigma); and shielding function F(xi); for the system PEA-organic solvents by intrinsic viscosity measurements

Journal of the Brazilian Chemical Society

Martha L. Cecopieri-gómez²  Joaquín Palacios-alquisira¹ 

[1] ,Instituto Mexicano del Petróleo Research and Development Program in Molecular Engineering México D. F. ,México

关键词: Flory binary interaction parameter;    hydrodynamic properties of poly(ethylene adipate);    Stockmayer-Fixman (SF) hydrodynamic model;    Debye-Bueche solution theory;    intrinsic viscosity;   

DOI  :  10.1590/S0103-50532005000300017

来源: SciELO

【 摘 要 】

In this work we present experimental data of the Flory binary interaction parameter, chi, of poly (ethylene adipate) PEA, a plasticizer material. We have used the viscometric method for measuring dilute PEA solutions in good solvents: benzene, chloroform and acetone. A procedure based on the Stockmayer-Fixman, (SF), hydrodynamic solutions theory, allows us to evaluate some thermodynamic parameters via the intrinsic viscosity [eta], measured in several good solvents. This method also estimates the unperturbed parameter, ktheta, and the steric hindrance parameter, (sigma), by viscosity measurements at constant temperature of 30ºC. By correlation of the molecular weight (M) and intrinsic viscosity data, according to the Stockmayer-Fixman (SF) solution theory model, values of Flory binary interaction parameter chi, equal to chi1,2 =0.1544 ± 0.01; chi1,2 =0.1631 ± 0.01; and chi1,2 =0.1922 ± 0.01, for PEA in benzene, chloroform and acetone, respectively, were obtained. In addition we applied the Debye-Bueche theory, in order to estimate values of: expansion factor (epsilon), shielding factor (xi) and depth of shielding (L) for the system PEA-organic solvents, by [eta] and (M) experimental data correlation. The results confirm that values obtained, correspond to "good solvents" for the PEA polymer.

【 授权许可】

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