A new durable antibacterial cotton fabric was successfully prepared by free-radical graft copolymerization of acrylic acid (AA) and itaconic acid (IA) onto a cotton fabric in an aqueous medium. Ammonium persulfate (APS) was used as the initiator in the presence of a crosslinker, methylene bisacrylamide (MBA). The nanocomposite hydrogel was obtained from in situ formation of silver nanoparticles from reduction of silver cations by sodium borohydride. A proposed mechanism for nanocomposite formation was suggested and the effect of ratio of IA to AA on water absorbency discussed. FTIR, UV-Vis, X-ray, and scanning electron microscopy were employed to characterize the structure of the prepared superabsorbent. The antibacterial activity of the hydrogel was tested qualitatively and quantitatively. Results showed that the silver nanoparticle-loaded fabric has potent antibacterial activity to Escherichia coli Gram-negative bacteria.
Imines of six new quinolin-5-ylamine derivatives 3(a-c) and 5(a-c) were synthesized by the reaction of quinolin-5-ylamine (1) with different aldehydes 2(a-c) and ketones 4(a-c). The chemical structures of the compounds were confirmed by UV-visible, FT-IR and 1H NMR spectral study. New compounds were screened for the antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl) method. Butylated Hydroxytoluene (BHT) was used as standard. All the compounds showed DPPH radical scavenging activity, where compound 3c was the best radical scavenger.
In this study, for the first time we report a highly selective and sensitive lutetium ions chemical optical sensor based on immobilization of a asymmetrically S–N Schiff’s base, namely N-(thien-2-ylmethylene)pyridine-2,6-diamine (TPD) on a triacetylcellulose membrane. This optode exhibits a linear range of 5.0 ×10-7 –1.0 ×10-5 M of the Lu(III) ion concentration with a detection limit of 9.3 ×10-8 M at a wavelength of 336 nm. The influence of responsible factors for improving sensitivity of the sensor was studied and identified. Response time of the newly designed optode was within 20-30 s depending on the Lu(III) ion concentration. Response of the optical sensor is independent of the pH of the solution in the range of 3.0–9.0. It manifests advantages of fast response time, low detection limit and most significantly, very good selectivity with respect to a number of lanthanide ions. The sensor can readily be regenerated with thiourea solutions and its response was reversible and reproducible. This optode was applied to the determination of Lu(III) in aqueous and CRM samples.
HDPE was functionalized with two different esters in an inert atmosphere at 160°C, under different experimental conditions by thermolysis method. The order of the functionalization and crosslinking reactions was determined. The C=C formation peak is assigned at 1610 cm-1.The percentage of functionalization was determined by FTIR spectroscopy method. Thermogravimetric analysis and differential scanning calorimetric methods were also used to study about the thermal properties of the functionalized HDPE.
An efficient and simple protocol of B-enaminones and B-enamino esters synthesis using nickel oxide under ultrasound sonication has been developed. Ultrasound sonication triggers the formation of enaminones under the mild reaction conditions. Nickel oxide was found to be efficient, heterogeneous, moisture stable, robust and recyclable catalyst.
Superabsorbent hydrogels based on poly(vinyl alcohol) were prepared by a crosslinking technique using glutaraldehyde as a crosslinker. The hydrogel structure was confirmed using scanning electron microscopy (SEM). Results from SEM observation showed a porous structure with smooth surface morphology of the hydrogel. We have systematically optimized the certain variables of hydrogel synthesis (i.e. the crosslinker concentration, poly(vinyl alcohol) content, time and temperature of crosslinking reaction) to achieve a hydrogel with maximum water absorbency. It was concluded that under the optimized conditions, maximum capacity of swelling in distilled water was equal to 231 g/g. The absorbency under load (AUL) of hydrogels was also measured. In addition, swelling ratio in various salt solutions was determined and the hydrogels exhibited salt-sensitivity properties.