ESTIMATION OF THERMODYNAMIC PARAMETERS FOR POLY(ETHYL METHACRYLATE) ISOPROPYL-ALCOHOL SYSTEM FROM INTRINSIC-VISCOSITY MEASUREMENTS

Intrinsic viscosities of poly(ethyl methacrylate) (PEMA) solutions in isopropyl alcohol (IPA) above and below the theta (theta) temperature (36.9-degrees-C) have been measured by using a capillary viscometer. The equation-of-state exchange energy (X12) and entropy (Q12) parameters were estimated as 62.82 J cm-3 and 0.03 J cm-3 K-1, respectively. The unperturbed dimension constant (K(theta)) and characteristic ratio (C(infinity)) were determined as 5.91 x 10(-4) dl Mol1/2 g-3/2 and 9.3 using the intrinsic viscosity data obtained at the theta temperature for PEMA in IPA. The polymer-solvent interaction parameters (chi1, chi2) were calculated from equation-of-state theory as a function of temperature. The value of the ratio of contact sites (s2/s1) is found to be 0.73 for this PEMA-IPA pair.