Refractometric study of polymers and their blends in solution

Abstract

Measurement of refractive index (nD) of poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG) in solution at 298 K is presented here. PVP has been investigated in nine different polar solvents including liquid PEG200 and PEG400, whereas PVA, PEG, and PVP+PVA and PVP+PEG blend have been investigated in water solution. High frequency limiting dielectric constant (Ɛ∞) has been taken as the square of the measured refractive index (Ɛ∞ =nD²). It is observed that the concentration dependent Ɛ∞ values of these systems exhibit linear behaviour. The Ɛ∞ values of the pure polymers have been determined from the measured Ɛ∞ values of their polymeric solutions. The effect of molecular weight of the polymers on the electronic polarization is discussed by considering comparative Ɛ∞ values of different molecular weight polymers. Results reveal that these polymers and their blends have high solubility in the used solvents, which is mainly due to the polymer-solvent hydrogen bond interactions.