Microwave assisted synthesis, characterization and thermoacoustical study of a β-naphthol-guanidine-formaldehyde copolymer resin

Abstract

The copolymer resin β-naphthol-guanidine hydrochloride-formaldehyde (β-NGF) has been synthesized by the condensation polymerization of β-naphthol and guanidine hydrochloride with formaldehyde in a 1 : 1 : 2 molar ratio of reactants in the presence of an acid catalyst under microwave irradiation. The synthesized copolymer has been characterized by spectral methods viz.¹H-NMR, ¹³C-NMR, IR and UV-visible spectroscopy. The surface analysis has been done by SEM. The ultrasonic velocity, density and viscosity of the β-NGF copolymer in pure ethanol at different temperatures and concentrations have been measured. Based on the data obtained, various acoustical parameters like adiabatic compressibility, intermolecular free length, acoustic impedance, relaxation time, relative association and Gibb's free energy have been calculated. From the data of acoustical parameters, the intermolecular interactions between β-NGF and ethanol have been discussed.