Heat-of-mixing data, obtained on blends of poly(ethylene oxide) (PEn) with whole and fractionated poly(vinyl acetate) (PVAc), were used to feed Patterson's theory of polymer-polymer miscibility. Negative values of mixing enthalpy, contact-energy term, interaction parameter and excess volume were obtained only for blends with the lowest molecular weight PVAc fraction. These results show that miscibility of PVAc with PEn strongly depends on its molecular weight. The calculated unfavourable excess volume term of the Patterson equation is small in comparison with the absolute value of the interaction term. Therefore, miscibility of PEn and low-molecular-weight PVAc is dictated by the weak specific interactions between different repeat units and by the entropic gain in the mixing process.
Посилання на статтю:
Thermodynamics of poly(ethylene oxide)- poly (vinyl acetate) blends / Yin Jinghua and G. C. Alfonso, A. Turturro and E. Pedemonte* // Polymer. – 1993. – Vol 34. – P. 1465-1470.