Physicochemical and Engineering Properties of Nanocomposite Films Based on Chitosan and Pseudoboehmite Alumina

Chitosan-based nanocomposite plastic films were developed by adding 0, 1, 3, and 5 % boehmite alumina (BAH) nanoparticles as a percentage of chitosan powder weight. The films were cast via solution. The effect of BAH content on the physicochemical and engineering properties of the resultant films were determined. The swelling, water vapor adsorption capacity, and transparency were significantly reduced with increased BAH content. The stability of the films against microbial degradation under high relative humidity also increased with BAH content. The water vapor permeability (WVP) reduced with increased temperature giving rise to negative activation energy values, which ranged between 2.08 and 3.36 kJ/mol. However, at constant temperature, inclusion of BAH did not have significant effect on water vapor permeability (WVP). WVP was predicted to high accuracy (r ²?=?0.984) using a full quadratic regression model. All the films had similar tensile and thermal behaviors. The implications of the findings are discussed based on prospective applications of the biodegradable film especially for fresh produce packaging.     

5‐Fluorouracil encapsulated magnetic nanohydrogels for drug‐delivery applications

For the first time, green‐tea (GT)‐based magnetic nanohydrogels were developed for drug‐delivery purposes. The hydrogel matrices were fabricated via the in situ polymerization of acrylamide with GT molecules. Magnetic nanoparticles were synthesized by the reduction of the 1:2 molar ratio mixture of ferrous sulfate heptahydrate and ferric chloride hexahydrate with an ammonia solution. A chemotherapeutic drug, 5‐fluorouracil, was chosen as a model drug, and its releasing profiles in the presence and absence of the external magnetic field were evaluated at a pH of 7.4. We observed that in the presence of the applied magnetic field, these magnetic nanohydrogels released 2.86% more drug than in the absence of a magnetic field. The magnetic nanohydrogels were characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometry, and transmission electron microscopy. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43921.     

Preparation and characterization of poly(ethylene glycol) stabilized nano silver particles by a mechanochemical assisted ball mill process

Nano silver particles with an average mean crystallite size of between 10 and 12 nm were synthesized from different molecular weights of poly(ethylene glycol) as a stabilizing agents, through solid state oxidation of silver nitrate using a higher energy planetary ball mill. Ultraviolet‐Visible spectra were used to confirm the synthesis of nano silver particles. The surface plasmon resonance bands were observed around 410 nm. Fourier transformed infrared spectrum, X‐ray diffraction, and transmission electronic microscopy techniques were used to characterize the nano silver particles synthesized. Thermal stability was determined using thermogravimetic analysis and the elemental composition of the sample was determined by energy dispersive X‐ray analysis. The nano silver particles synthesized, exhibited very good antibacterial activity against Gram‐positive bacteria (Bacillus) and Gram‐negative bacteria (Pseudomonas aeruginosa). Based on the obtained results, it was additionally explored that the size and the stabilization of the nano silver particles synthesized, strongly depend on the molecular weight of poly(ethylene glycol). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43027.     

Controlled dual release study of curcumin and a 4‐aminoquinoline analog from gum acacia containing hydrogels

The potential of gum acacia containing hydrogels as controlled dual‐drug delivery systems for antiprotozoal agents was investigated. 4‐Aminoquinoline analog and curcumin were selected as model drugs because they exhibit antiprotozoal activity. The maximum release time was greater for curcumin than for the 4‐aminoquinoline analog at 37°C, thereby enabling the active ingredients to work over different periods of time. 4‐Aminoquinoline analog exhibited a short term release profile while curcumin exhibited a sustained and long term release profile. The release profiles of the drugs were found to be influenced by the degree of crosslinking of the hydrogel network with gum acacia. The release profiles were analyzed using a power law equation proposed by Peppas. The release mechanism of the 4‐aminoquinoline was found to be anomalous transport while that of curcumin was quasi‐Fickian diffusion mechanism in all the hydrogel networks according to the release exponent. The preliminary results suggest that these systems are potential dual‐drug delivery system for antiprotozoal agents with different pharmacokinetics. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41613.     

Tensile properties of polymethyl methacrylate coated natural fabric Sterculia urens

The newly identified natural fabric from the tree of Sterculia urens was coated with Polymethyl methacrylate. The tensile properties of both the uncoated and Polymethyl methacrylate coated fabrics were studied. The tensile parameters such as maximum stress, Young's modulus and % elongation at break were determined using a Universal Testing Machine. The effect of alkali treatment and the Polymethyl methacrylate coating on tensile properties of the fabric was studied. The morphology of the fabric before and after alkali treatment and Polymethyl methacrylate coating was studied using the scanning electron microscopy and polarized optical microscopic techniques respectively. The improvement in the tensile properties on Polymethyl methacrylate coating was attributed to the filling up of the void regions of the uniaxial fabrics with Polymethyl methacrylate facilitating continuity.     

Preparation of antibacterial temperature‐sensitive silver‐nanocomposite hydrogels from N‐isopropylacrylamide with green tea

This article reports the temperature‐sensitive, green tea (GT)‐based silver‐nanocomposite hydrogels for bacterial growth inactivation. The temperature‐sensitive hydrogels were prepared via free‐radical polymerization using temperature‐sensitive N‐isopropylacrylamide (NIPAM) monomer with GT as the hydrogel matrix. The nanocomposite hydrogels were encapsulated with silver ions via swelling method, which was later reduced to silver nanoparticles using Azadirachta indica leaf extract. The temperature‐sensitive silver nanocomposite hydrogels were analyzed by using Fourier transforms infrared, UV–visible spectroscopy, differential scanning calorimetry–thermogravimetric analysis, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The prepared hydrogels exhibited higher phase volume transition temperature than the NIPAM. The inhibition zone study of the inactivation of bacteria on the developed hydrogels was carried out against Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus), which revealed that the prepared hydrogels are helpful for the inactivation of these bacteria due to the high stabilization of antibacterial properties of the silver nanoparticles. The developed hydrogels are promising for biomedical applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45739.