Gyanaranjan Sahoo

Nano gold decorated reduced graphene oxide wrapped polymethylmethacrylate for supercapacitor applications

Herein, a simple one step synthetic protocol was adopted to fabricate nano gold decorated reduced graphene oxide (r-GO) wrapped polymethyl methacrylate nanohybrids (PMMA/r-GO/Au) for symmetric supercapacitor applications. Synthesized nanohybrids were characterized by UV-visible, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), and high resolution transmission electron microscope (HRTEM). The gold nanoparticles were found to be distributed uniformly on the surface of r-GO layers with a basement of PMMA. Thermal stability of the fabricated PMMA/r-GO/Au nanohybrid was investigated by thermogravimetric analysis (TGA) and an improvement in thermal stability was observed as compared to PMMA and PMMA/r-GO nanohybrids. Electrochemical performance of the PMMA/r-GO/Au nanohybrids was investigated as electrode material in three electrode systems in addition to a symmetric cell in a two electrode system with 1 M H2SO4 medium. The fabricated PMMA/r-GO/Au nanohybrid-based symmetric cell delivered significantly higher energy density of 29.46 W h kg−1 at a power density of 235 W kg−1 as compared to that of the PMMA/r-GO-based symmetric cell. The improved energy storing capacity of this material was assigned from the synergistic effect of r-GO and Au NPs in a typical layered arrangement. The substantial improvement in electrochemical performance may enable the synthesized ternary nanohybrid for supercapacitor applications.

Carbon quantum dot tailored calcium alginate hydrogel for pH responsive controlled delivery of vancomycin

&NA; Herein, we demonstrate the preparation of highly luminescent carbon quantum dots (CQDs) from Aloe vera leaf gel; in just 2 h at 250 °C through carbonization pathway. The prepared CQDs are structurally characterized with high resolution transmission electron microscopy (HRTEM), hydrodynamic diameter, surface polarity, Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), Raman, UV–visible absorption spectrophotometry and fluorescence spectroscopy. The functional carbon nanoparticles are observed as non‐cytotoxic materials. The biocompatibility, less cytotoxicity and high aqueous dispersibility of as‐synthesized CQDs are motivated to design carbon quantum dot (CQD) tailored calcium alginate (CA) hydrogel films with an aim to controlled delivery of glycopeptides antibiotic vancomycin in the gastrointestinal tract (GI). With CQD, the drug loading capacity of CA/CQD film is increased to 89% from 38% (CA film), whereas; with &bgr;‐cyclodextrin (&bgr;‐CD) the vancomycin uptake capacity is increased more, 96%. The release of vancomycin through CA/CQD film is more pronounced at pH 1.5, close to the pH of the stomach and it is found that in pH 1.5 with &bgr;‐CD, the release rate of vancomycin is lowered, 56% in 120 h. The high drug uptake capacity (96%) and lower release rate (56% in 120 h) of CA/CQD hydrogel film in pH 1.5 with &bgr;‐CD can be used for its applicability as drug delivery vehicle for controlled release of vancomycin into the stomach region and therefore it can offer a potential option for oral administration of vancomycin. Graphical abstract Figure. No caption available.

Polymer-Based Bionanocomposites for Future Packaging Materials

Packaging technology is mainly dealing with the safety storage and hygienic handling of daily needs and undergoes in continuous modification with time as per the choice of the consumers. With the ever-increasing market race, psychological aspect of the consumer behavior is also reflected in the packaging technology. For easy production and low cost of synthetic plastic materials, it has won the prime interest in packaging field. But, environmental issues lead the system to run behind the fabrication of eco-friendly bionanocomposites with incorporation of nanomaterials in renewable, biodegradable polymers in order to obtain bionanocomposites with improved fire retardant, oxygen barrier, thermal and mechanical properties. This chapter focusses some important basics of polymer-based bionanocomposites for packaging applications. The mechanical, fare retardant, thermal and gas barrier properties are improved substantially with incorporation of nanomaterials with biopolymers. Herein, the commercial, physiological and safety aspects of packaging materials are also discussed for the promotion of polymer-based nanocomposite as a future smart material for packaging products.

Nanocomposites of Polyurethane Filled with CNTs

Abstract Carbon nanotube (CNT)-filled polyurethane nanocomposites were designed through in situ polymerization and melt mixing techniques. In order to improve the compatibility with the polyurethane matrix, pristine CNTs were converted into polar reinforcement by means of surface modification with organic functional groups. The modified CNTs were allowed to disperse within polyurethane (PU), thermoplastic PU, waterborne PU, and a blending of PU and polylactic acid. The nanostructure orientation of chemically modified CNTs within a PU network was evidenced through scanning electron microscopy and transmission electron microscopy. The chemical interaction between modified CNTs and PU matrix was investigated through Fourier transform infrared spectroscopy analysis. Fabricated PU/CNT nanocomposites were found to be blessed with improved thermal, mechanical, and rheological properties and, therefore, they may be used as advanced functional materials in automotive technologies.

Antimicrobial Properties of Nanogold-Imprinted Starch Bionanocomposites

ABSTRACT Nanogold-imprinted starch bionanocomposites of various compositions were synthesized by “one-pot reaction” with in situ generation of nanogold. Bionanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscope and high-resolution transmission electron microscope. The electrical conductivity of nanocomposites was enhanced because of dispersion of nanogold in the starch. Antimicrobial activity of starch was increased due to incorporation of nanogold. The bionanocomposites were resistant towards dilute acid and alkali with little scarification in biodegradable properties. The enhanced thermal, gas barrier and antimicrobial properties may enable the synthesized materials for packaging applications. GRAPHICAL ABSTRACT

Biomass-based nanocomposite for packaging applications

The upgrowing demand of eco-friendly packaging materials instead of nonbiodegradable, nonrenewable synthetic polymer-based packaging materials has compelled the researcher to think of the fabrication of biomass-based nanocomposites for sustainable packaging applications. Biomass-based nanocomposites are mainly fabricated by the solution casting technique with incorporation of different nanomaterials within different host polymers. The synthesized biomass-based nanocomposites can be structurally characterized with X-ray diffraction and Fourier transform infrared studies, whereas the morphological analysis is carried out through field emission scanning electron microscopy and high-resolution transmission electron microscopy. The mechanical, thermal, and gas barrier properties of the synthesized nanocomposites are focused in comparison with the individual components. The enhanced thermal, mechanical, and improved gas barrier properties may enable the synthesized biomass-based nanocomposites for packaging applications.

Oxygen Permeability of Layer Silicate Reinforced Polymer Nanocomposites

Reinforcement of organically modified nanoclay into different synthetic and biopolymer matrices was performed by several techniques. For high density polyethylene (HDPE) and polyamide (PA6) based nanocomposites, single screw compounding process was adopted, whereas; for polymethylmethacrylate (PMMA), polyacrylonitrile (PAN) based nanocomposites in situ polymerization technique was taken into consideration. For protein and biopolymer based nanocomposites; nano clays were made to disperse through solution casting technique. The structural analysis of all the polymer/clay nanocomposites or bionanocomposites was performed through X-ray diffraction (XRD) and Fourier transform infrared (FTIR) studies, whereas; the morphological analysis was carried out through transmission electron microscope (TEM). The oxygen permeability of nano clay reinforced polymer nanocomposites was measured as function of clay content and pressure. It was found to be decreased with increase in clay content as compared to their neat polymers. Along with the clay content, ultrasonic treatment also affect the nature of dispersion of nanoclay and thereby the oxygen permeability of the fabricated nanocomposites. The enhanced obstacle towards the path of gas transportation within the fabricated polymer nanocomposite may enable the material for food packaging applications.

Manufacturing of Chemically Modified Date Palm Leaf Fibre-Reinforced Polymer Composites

Chemically modified fibre-reinforced polymer composites were manufactured by melt mixing method with several fractions of the modified fibres. Before proceeding to melt mixing method, fibres were made compatible by different chemical modifications. The interaction between date palm leaf fibres and polymeric matrix was examined by Fourier transform infrared (FTIR) spectroscopy, whereas the morphology of chemically modified DPL fibres and DPL fibre-reinforced biocomposites (i.e., polyvinylpyrrolidone (PVP)/DPL and polyvinyl alcohol (PVA)/DPL) was studied by using field emission scanning electron microscopic (FESEM) technique. Because of the strong interfacial interaction between polymers and fibres, mechanical properties were improved. It was found that the tensile strength, elongation at break, and loss modulus of polymer composites were compared with that of virgin polymeric matrix of PVP and PVA. The thermal and conducting properties of composites were studied by using thermogravimetric analysis.