Rajabali Ebrahimi

Polyacrylate hydrogels containing starch, ZeSe and Fe3O4 nanoparticles were obtained. The polymerization process was carried out in an ultrasonic field. The structure (SEM, FTIR), swelling properties and the ability of hydrogels to adsorb dyes (methylene blue, methyl orange, methyl red and Eriochrome black T) and heavy metals (Cu²⁺) from wastewater were investigated. Hydrogels containing AgCl nanoparticles were also obtained.

Polyacrylate hydrogels containing starch, ZeSe and Fe3O4 nanoparticles were obtained. The polymerization process was carried out in an ultrasonic field. The structure (SEM, FTIR), swelling properties and the ability of hydrogels to adsorb dyes (methylene blue, methyl orange, methyl red and Eriochrome black T) and heavy metals (Cu²⁺) from wastewater were investigated. Hydrogels containing AgCl nanoparticles were also obtained.

The powerful waves of ultrasound are used in polymerization reactions in the absence of initiator. In the present research, the hydrogel was obtained by water‐soluble acrylic monomers, starch, and the crosslinking agent of methylene bis acrylamide dissolved in water/glycerol dual. The hydrogel is formed by these waves only in viscous environments such as glycerol, heat, or initiator is not required. In the presence of ultrasound, the time of product formation is reduced to a few minutes. Moreover, the resulting hydrogels have more uniform microscopic structure and are more swollen. The structure of the grafted hydrogel was examined meanwhile the hydrogel swelling in three environments of pure water, saltwater, and under pressure was measured. It was found that the grafted hydrogel has double swelling rate in the pure. Also, after loading the ciprofloxacin into the synthesized hydrogel, this drug is released 99% in initial 20 min. 0.1 g starch in 1.5 g acrylic hydrogel has the most drug release. The high swelling capacity in the pH ranges of 5–9 shows the extension of drug application in acidic or alkaline environments, and also after several using the gel and the capacity of water absorbency, which was about 70% of its initial water, indicates the perfect reusability capacity of the gel.

Ciprofloxacin is an antibacterial fluoroquinolone that stops the DNA synthesis, after penetration into the bacterial cells. This drug is applied in the curing of bacterial infections, as well as in antibiotics to treat urinary infections in women, infectious diarrhea and typhoid fever. The objective of the present work is to study controlled release of ciprofloxacin by hydrogel prepared by ultrasound. For this, first the swelling properties of hydrogel and then the absorption of drug were evaluated. The swollen hydrogel was dried in oven (50°C) and was ready for release experiments. During release, the loaded powder of the hydrogel was added to a buffer solution of pH 7.4, similar to human body condition. Then drug concentration was measured using a UV-visible (UV-Vis) spectrophotometer and a calibration curve. The results showed that the hydrogel is sensitive to pH, which makes it a good candidate for ciprofloxacin delivery in intestine. In addition, it was shown that the drug absorption is proportional with the swelling content of the hydrogel and the drug concentration in the loading process. The chemical structure and morphology of the hydrogels and loaded drug were characterized using Fourier transform infrared, UV-Vis, scanning electronic microscopy and thermal gravimetric analysis spectroscopy. According to the results presented here, acrylic-based hydrogels can be used in biomedical fields, especially for controlled drug release.

The present work was an attempt to investigate the parameters that can affect the process of hydrogel formation in the presence of ultrasound. These parameters were concentrations of the reactants, the reaction medium, and acoustic factors. The monomers were acrylic acid and acrylamide, and the cross-linker was methylene bis acrylamide. Pulsed power ultrasound was irradiated to the reaction mixture from the tip of a probe unit. The swelling behaviors of the obtained hydrogels were investigated in various buffer solutions, at different temperature values, and using different ionic salts. The results show that ultrasonic irradiation significantly reduces reaction time and increases efficiency. Additionally, increasing glycerol in the solution changes the viscosity of the reaction for the better and increases the reaction rate. However, ionic strength and pH were not significantly effective in this respect. Another major finding was that increasing ultrasonic power and pulse hastens the reaction. Cationic salts were effective in this order: Na⁺>Ca²⁺>Fe³⁺. The hydrogel was responsive to pH, temperature, and salts. These findings provide a better understanding of hydrogel synthesis and enable us to control the pertinent parameters.

Viscometry is a valid and practical approach for monitoring the degradation of polymers in solution. In this work, at constant power and pulse, the effects of different operating parameters such as time of irradiation, temperature, solution concentration, volume, solvent, and immersion depth of horn on the rate of degradation have been investigated in aqueous solution using laboratory scale operation. A method of viscometry was used to study the degradation behavior of aqueous dispersions of microgels. The experimental results show that the viscosity of polymer solution decreased with an increase in the ultrasonic irradiation time and approached a limiting value. The present work has enabled us to understand the role of the different operating parameters in deciding the extent of viscosity reduction in aqueous dispersions of microgels and also the controlling effects of them.