Modification of Poly Ethylene Glycol with 4, 4-Azo Di Benzoic Acid and Study of Its Physical Properties

Polyethylene glycol 20000 was modified by copolymerization with 4, 4-Azo di benzoic acid, using cold-warm esterfication. The modified copolymer has been characterized by Fourier transform infrared spectrophotometer (FT-IR) which showed characteristic vibrational bands of OH, CO and N=N groups. The modified copolymer was subjected to differential scanning colorimeter (DSC), conductivity and swelling measurements. The obtained results of the thermal behavior (DSC) for the different percentage of prepared copolymers were (I=10% PEG +10% 4, 4-Azo di benzoic acid)= 54.2^◦C, as well as (II=20%) = 68.6◦C, (III=30%) = 81.5◦C, (IV=40%) = 93.3◦C and (V=50%) = 120 ◦C. This means that perfect results when the polyethylene glycol 50% mixed with 50% of 4, 4-Azo di benzoic acid. While the conductivity of all copolymer in an aqueous phase with varying chain lengths of PEG reacted with 4, 4-Azo di benzoic acid, in different percentage were (I) = 75.6, (II) = 151.8, (III) = 165.3, (IV) = 226 and (V) = 277 Λm(S.cm² .mol^-1 ). In ethanol, the copolymers were observed to have electrolyte behaviors. The solubility of the prepared copolymer was tested in different solvents at 25◦C. It is highly soluble in DMSO and DMF and insoluble in other solvents. The experiment of measuring the degree of swelling under room temperature, in equal periods of time, showed good water uptake and required ~12 hours for reaching the equilibrium for the different percentage of prepared copolymers.