Study of excess acoustical and thermo-dynamical parameters of binary solutions of polypropylene glycol-400 and n-alkanols at 303 K

摘要

The study of the acoustical and thermodynamic properties of binary mixtures helps to obtain information on various molecular features of the mixtures. As polypropylene glycol (PPG) is an industrially important polymer and the alcohols are excellent solvents for many polymers, this fact has tingled our interest to study the molecular interactions in the solutions of PPG and alcohols. In the present investigation, using ultrasonic velocity and density data, taken from literature, several excess parameters e.g. excess ultrasonic velocity (U~E), excess acoustic impedance (Z~E), excess isentropic compressibility (K_(s~E)), excess intermolecular free length (L_(F~E)), excess internal pressure (π_(i~E)) and excess free volume (V_(F~E)) for binary solutions of polypropylene glycol-400 with ethanol, 1-propanol and 1-butanol have been determined at 303 K. The behavior of polymeric solutions is discussed in terms of molecular interactions among different molecules. The negative values of K_(s~E), L_(F~E), and V_(F~E) over the entire range of mole fraction indicate the presence of strong associative interactions and suggest the possibility of hydrogen bonding between the different molecules, clathrate formation and likelihood of complex formation in the systems under study. The effect of the increasing size of the alkyl group of alkanols, on the intermolecular interactions has also been discussed.