Temperature dependent physicochemical studies of polyethylene glycols (PEG-400 and PEG-4000) in aqueous sorbitol solutions

From the measurements of density and speed of sound, the apparent molar properties and the partial molar properties have been determined to study the interactions of two polyethylene glycols i.e. polyethylene glycol 400 and polyethylene glycol 4000 in aqueous solutions of sorbitol at experimental pressure p = 0.1 MPa and temperatures T = (288.15-318.15) K. Evaluation of partial molar volume (Vϕo), apparent molar volume (Vϕ) and partial molar volumes of transfer (ΔVϕo) is done using density measurements. For the determination of partial molar isentropic compression (Kϕ, so), apparent molar isentropic compression (Kϕ, s), and partial molar isentropic compression of transfer (ΔKϕ, so), the ultrasonic speed measurements have been utilized. The limiting apparent molar expansibilities (Eϕ0) and its first order derivatives (∂Eϕ0/∂T)p are also calculated. Further, with the aid of partial molar isentropic compression of transfer and partial molar volumes of transfer, pair and triplet coefficients are determined. Through the scrutiny of these evaluated parameters, the results are elucidated based upon contending patterns of physicochemical interactions of co-solutes and solvents prevailing in present ternary liquid mixtures.