No abstract

Copolymers were prepared by gamma irradiation of acrylic acid (AAc)/plasticized starch (PLST)/carboxymethyl cellulose (CMC) mixtures in aqueous solutions. The effect of AAc ratio and gamma irradiation dose on the gel content, swelling (%) and tensile mechanical properties was investigated. The PAAc-co-PLST/CMC copolymers were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and surface morphology by scanning electron microscopy (SEM). The thermal stability was further investigated by determining the activation energy by three different methods based on Coats-Redfern, Broido and the Horowitz -Metzger approximation equations. As an application, the removal of copper and nickel ions by the copolymer hydrogel was also studied. The results indicated that the graft copolymer hydrogels have higher affinity for Ni +2 than Cu +2 ions.

Hydrogels of (carboxymethyl cellulose/polyacrylamide/polyprotic acids) were synthesized via gamma‐irradiation as green initiator. The polyprotic acids were used are oxalic, tartaric, citric and maleic. Effects of irradiation dose and polyprotic acids concentration on gelation (%) and swelling (%) are investigated. The swelling of hydrogels were conducted in the range of pH levels are from 1 to 12 at 37°C. The outcome hydrogels were characterized different techniques of Fourier transform infrared spectroscopy, thermal gravimetric analysis and derivative thermogravimetry, X‐ray diffraction, and scanning electron microscopy. The results confirmed the formation of respective hydrogels. Hydrogels were exploited in release of nicotinic acid as model of drug release. Dry tablets from hydrogels were fabricated as cylindrical discs. Dry hydrogels tablets were subjected to two different pH levels (i) simulated gastric fluid of pH level 1.2 and (ii) simulated intestinal fluid of pH level 7.5. The outcome results showed that there is a difference of nicotinic acid release quantity between the two pH levels. Further, different kinetic models of zero‐order, Korsmeyer–Peppas, Higuchi and Weibull were used to fit the experimental data. Through the results declared that the best fitting model was Weibull.