Effect of temperature and solvents on ultrasonic speed and thermo-acoustic parameters of epoxy resin of (2E, 6E)-bis (4-hydroxy benzylidene)-4-methylcyclohexanone solutions at four different temperatures

The density (), viscosity () and ultrasonic speed (U) of 1, 4-dioxane (DO), tetrahydrofuran (THF), chloroform (CF) and solutions (0.25-5 wt%) of epoxy resin of (2E, 6E)-bis(4-hydroxy benzylidene)-4-methylcyclohexanone have been investigated at 298, 303, 308 and 313 K to understand molecular interactions in solutions of different polarity. Various acoustical and thermodynamic activation parameters such as acoustical impedance (Z), adiabatic compressibility (a), internal pressure (), free volume (Vf), intermolecular free path length (Lf), van der Waals constant(b), viscous relaxation time (), classical absorption coefficient (f2)cl, Rao`s molar sound function (Rm) and solvation number (Sn) were determined using, and U data and correlated with concentration (C) at four different temperatures (T). Good to excellent correlation between a given parameter and concentration is observed at all T. Linear or non-linear increase or decrease of studied acoustical and thermodynamic parameters with concentration of epoxy resin at different temperatures indicated existence of strong molecular interactions (solvent-solute and solute-solute) in the solutions. The non-linear increase of Sn with concentration of epoxy resin further supported the existence of strong molecular interactions and structure forming tendency of EMBHBC. The competing solvent-solute and solute-solute interactions are also supported by thermodynamic activation parameters (G, H and S).