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Antimicrobial and swelling behaviors of novel biodegradable corn starch grafted/poly(4-acrylamidobenzoic acid) copolymers

Abd El-Ghany, Nahed A., Abdel Aziz, Mohamed S., Abdel-Aziz, Marwa M., Mahmoud, Zain
International journal of biological macromolecules 2019 v.134 pp. 912-920
Fourier transform infrared spectroscopy, Gram-negative bacteria, Gram-positive bacteria, X-ray diffraction, ammonium persulfate, aqueous solutions, biodegradability, composite polymers, copolymerization, corn starch, free radicals, fungi, gelatinization, scanning electron microscopy, sodium bisulfite, sodium chloride, starch, temperature, thermal stability, thermogravimetry
Novel antimicrobial copolymers resulted from free radical copolymerization of gelatinized corn starch in aqueous solution with different amounts of 4-acrylamidobenzoic acid monomer using ammonium persulfate (APS)/sodium bisulfite (NaHSO3) as a redox initiator. The grafting copolymerization was evidenced by FTIR, 1HNMR, scanning electron microscopy (SEM) and X-ray diffraction. The thermal stability was improved after the grafting reaction as detected from IPDT values calculated from the thermogravimetric analysis. The effect of changing grafting parameters (initiator concentration, monomer concentration, reaction time and temperature) on graft copolymerization were studied by measuring the grafting percentage (%G), grafting efficiency (%GE) and homopolymer percentage (%H). The optimum grafting conditions were determined as follows: Initiator concentration [I] = 3 × 10-2 mol/L, monomer concentration [M] = 0.25 mol/L, reaction temperature = 65 °C and reaction time = 2 h. The prepared copolymers exhibited swelling ability in both water and 0.9% saline solution. The antimicrobial study revealed a high degree of inhibition against different strains of Gram-positive bacteria, Gram-negative bacteria and fungi when compared with neat starch.