Densities and viscosities for binary mixtures of polyoxymethylene dimethyl ethers with different CH2O chain length n = 2, 3, 4 at different temperatures

•Densities and viscosities for the binary mixtures of PODE2-PODE3, PODE2-PODE4, PODE3-PODE4 were measured.•The VE and Δη for binary mixtures were calculated and correlated.•The ΔG∗E for binary mixtures were also calculated and correlated.

Experimental densities and viscosities for the binary mixtures of polyoxymethylene dimethyl ethers with different CH2O chain length n = 2, 3, 4 were measured over a temperature range of 288.15 K-313.15 K and at the atmospheric pressure of 0.1 MPa. It is found that the order of densities and viscosities for pure components is PODE2 < PODE3 < PODE4 at the same temperature. Meanwhile, for binary mixtures (PODE2-PODE3, PODE2-PODE4, PODE3-PODE4), the densities and viscosities decreased with the increase of mole fraction of light component. On the basis of experimental data, the excess molar volumes and the viscosity deviations for the binary mixtures were calculated and correlated by the Redlich-Kister equation, while the excess Gibbs energy of activation for binary mixtures (PODE2-PODE3, PODE2-PODE4, PODE3-PODE4) were also calculated and correlated. The results indicated that the difference of the CH2O chain length has a significant influence on the densities and viscosities of binary mixtures of polyoxymethylene dimethyl ethers.

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