Synthesis, characterization, and thermal degradation of p-chloroacetophenone oxime based polymers having biological activities

摘要

A monomer, p-chloroacetophenone oxime (CAO), has been synthesized from p-chloroacetophenone and hydroxylamine hydrochloride and its copolymer resin p-chloroacetophenone oxime-formaldehyde (CAO-F) has been synthesized from p-chloroacetophenone oxime (CAO) and formaldehyde in 1: 2M proportion. A terpolymer resin p-chloroacetophenone oxime-formaldehyde-benzoic acid (CAO-F-BA) has also been synthesized by condensation of p-chloroacetophenone oxime (CAO), benzoic acid (BA), and formaldehyde (F) in 1: 1: 2M proportion in the presence of hydrochloric acid. The structures of monomer, copolymer, and terpolymer have been investigated by FT-IR, ~1H-NMR, and pyrolysis (GC/MS) techniques. Molecular weight and polydispersity index have been determined by gel permeation chromatography. Detailed thermal degradation studies of polymers have been carried out to ascertain its thermal stability. Multiple linear regression (MLR) method has been used to calculate activation energy (E_a) and frequency factor (Z). Thermodynamic parameters such as free energy (G*), entropy change (δS*), and rate constant for activation (k _r) have also been evaluated on the basis on Ozawa-Flynn-Wall method. Softening temperatures (T_s) of these resins have been obtained from differential scanning calorimetry (DSC). All the synthesized resins have shown reasonably good antimicrobial activities as compared to standard drugs.