Sarat K. Swain

Synthesis of gas barrier starch by dispersion of functionalized multiwalled carbon nanotubes

Nanocomposite films were prepared successfully by simple solution casting method from plasticized starch/functionalized multiwalled carbon nanotubes (PS/f-MWCNTs). The interaction of starch with functionalized multiwalled carbon nanotube (f-MWCNT) was evidenced by ultraviolet-visible (UV-vis) spectroscopy and Fourier transforms infrared (FTIR) spectroscopy. The morphological and thermal properties of the composite films were investigated using scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The electrical conductivity of the composites was increased significantly by sixteen times, from 0.1×10(-9) to 1.6×10(-9) S/cm. This reveals better dispersion of f-MWCNT with low concentration of f-MWCNT. The oxygen permeability of the composites was reduced by half as compared to virgin PS. This indicates better dispersion of f-MWCNT in PS matrix due to formation of strong hydrogen bonding with PS matrix.

Soy Protein/Clay Bionanocomposites as Ideal Packaging Materials

Soy protein-based bionanocomposites were prepared via solution intercalation with incorporation of the organoclay of different concentrations. The composites were characterized through UV-Visible and Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Thermal resistance of the materials was assessed by thermogravimetric analysis (TGA). The results showed a significant improvement in thermal resistance and glass transition temperature of the bionanocomposites with increase in clay content. The results of oxygen permeability of the nanocomposite films showed a substantial improvement in oxygen barrier property upon clay loading, which could enable the nanocomposites suitable as packaging materials.

Cellulose nanobiocomposites with reinforcement of boron nitride: Study of thermal, oxygen barrier and chemical resistant properties

A series of cellulose based nanobiocomposites (cellulose/BN) were prepared with incorporation of various percentage of nano boron nitride (BN). The interaction between cellulose and boron nitride was studied by Fourier transform infrared spectroscopy (FTIR). The structure of cellulose/BN nanobiocomposites was investigated by XRD, FESEM, and HRTEM. It was observed that the boron nitride nanoparticles were dispersed within cellulose matrix due to intercalation and partial exfoliation. The quantitative identification of nanobiocomposites was investigated by selected area electron diffraction (SAED). Thermal stabilities of the prepared nanobiocomposites were measured by thermo gravimetric analysis (TGA) and it was found that thermal stability of the nanobiocomposites was higher than the virgin cellulose. The oxygen barrier property of cellulose/BN nanobiocomposites was measured using a gas permeameter and a substantial reduction in oxygen permeability due to increase in boron nitride loading was observed. Further it was noticed that the chemical resistance of the nanobiocomposites was more than the virgin cellulose. Hence, the prepared nanobiocomposite may be widely used for insulating and temperature resistant packaging materials.

Phenylboronic acid functionalized reduced graphene oxide based fluorescence nano sensor for glucose sensing.

Reduced graphene has emerged as promising tools for detection based application of biomolecules as it has high surface area with strong fluorescence quenching property. We have used the concept of fluorescent quenching property of reduced graphene oxide to the fluorescent probes which are close vicinity of its surface. In present work, we have synthesized fluorescent based nano-sensor consist of phenylboronic acid functionalized reduced graphene oxide (rGO-PBA) and di-ol modified fluorescent probe for detection of biologically important glucose molecules. This fluorescent graphene based nano-probe has been characterized by high resolution transmission electron microscope (HRTEM), Atomic force microscope (AFM), UV-visible, Photo-luminescence (PL) and Fourier transformed infrared (FT-IR) spectroscopy. Finally, using this PBA functionalized reduced GO based nano-sensor, we were able to detect glucose molecule in the range of 2 mg/mL to 75 mg/mL in aqueous solution of pH7.4.

Synthesis of thermal and chemical resistant oxygen barrier starch with reinforcement of nano silicon carbide.

Starch/silicon carbide (starch/SiC) bionanocomposites were synthesized by solution method using different wt% of silicon carbide with starch matrix. The interaction between starch and silicon carbide was studied by Fourier transform infrared (FTIR) spectroscopy. The structure of the bionanocomposites was investigated by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). Thermal property of starch/SiC bionanocomposites was measured and a significant enhancement of thermal resistance was noticed. The oxygen barrier property of the composites was studied and a substantial reduction in permeability was observed as compared to the virgin starch. The reduction of oxygen permeability with enhancement of thermal stability of prepared bionanocomposites may enable the materials suitable for thermal resistant packaging and adhesive applications.

Dispersion of SiC nanoparticles in cellulose for study of tensile, thermal and oxygen barrier properties.

Cellulose/silicon carbide (cellulose/SiC) nanobiocomposites were prepared by solution technique. The interaction of SiC nanoparticles with cellulose were confirmed by Fourier transformed infrared (FTIR) spectroscopy. The structure of cellulose/SiC nanobiocomposites was investigated by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The tensile properties of the nanobiocomposites were improved as compared with virgin cellulose. Thermal stabilities of cellulose/SiC nanobiocomposites were studied by thermogravimetric analysis (TGA). The cellulose/SiC nanobiocomposites were thermally more stable than the raw cellulose. It may be due to the delamination of SiC with cellulose matrix. The oxygen barrier properties of cellulose composites were measured using gas permeameter. A substantial reduction in oxygen permeability was obtained with increase in silicon carbide concentrations. The thermally resistant and oxygen barrier properties of the prepared nanobiocomposites may enable the materials for the packaging applications.

Interpenetrating Polymer Network PVA/PAA Hydrogels

ABSTRACT A new type of interpenetrating polymer network (IPN) hydrogel based on polyvinyl alcohol (PVA) networking with difuctional monomer, acrylic acid (AA), and its polymer, polyacrylic acid (PAA), generated in situ, were prepared by a non-conventional emulsion method without any added crosslinker, using benzoyl peroxide as initiator and sodium chloride as additive. Structure and bonding in hydrogel due to interpenetrating network were confirmed by infrared spectroscopy. The networking was optimized by variation of reaction parameters such as concentrations of additive, monomer, time, and temperature. The response of the hydrogels with and without NaCl was observed by study of their swelling kinetics, and their apparent activation energies for diffusion (Ed) of water were calculated to be 29.28 and 35.97 J mol−1 K−1 with and without NaCl, respectively. The conductivity and pH were measured at different temperatures. The conductivity decreased largely with temperature whereas pH increased in presence of NaCl. The effect of swelling ratio was studied by variation of AA percentage and the optimal PVA/AA was determined. Biodegradability of the polymeric network was studied by culture media and the surface morphology investigated by scanning electron microscopy (SEM).

Oxygen Barrier of Multiwalled Carbon Nanotube/Polymethyl Methacrylate Nanocomposites Prepared by in situ Method

Multiw alled carbon nanotubes (MWCNTs)/poly(methyl methacrylate) (PMMA) nanocomposites were prepared by ultrasonic assisted emulsifler free emulsion polymerization technique with variable concentration of functionalized carbon nanotubes. MWCNTs were functionalized with H2SO4 and HNO3 with continuing sonication and polished by H2O2. The appearance of Fourier transform infrared absorption bands in the PMMA/MWCNT nanocomposites showed that the functionalized MWCNT interacted chemically with PMMA macromolecules. The surface morphology of functionalized MWCNT and PMMA/MWCNT nanocomposites were studied by scanning electron microscopy. The dispersion of MWCNT in PMMA matrix was evidenced by high resolution transmission electron microscopy. The oxygen permeability of PMMA/MWCNT nanocomposites gradually decreased with increasing MWCNT concentrations.

Emulsifier-free emulsion polymerization of acrylonitrile: Effect of in situ developed Cu(II)/glycine chelate complex initiated by monopersulfate

The catalytic effect of various Cu(II) salts and Cu(II) chelate complexes of certain amino acids on the emulsion polymerization of acrylonitrile in the absence of added emulsifier was investigated in experiments. The CuSO4/glycine chelate complex was chosen for a detailed kinetic study of acrylonitrile polymerization. The polymerization was studied at varying concentrations of initiator, monomer, Cu(II), glycine, solvents, and TiO2 over a temperature range of 30–60°C. The overall activation energy and the viscosity average molecular weight of the polymer were computed. From the kinetic and spectrophotometric studies, the mechanism of KHSO5 decomposition by the Cu(II)/glycine complex and initiation of polymerization was suggested.

Barrier properties of nano silicon carbide designed chitosan nanocomposites.

Nano silicon carbide (SiC) designed chitosan nanocomposites were prepared by solution technique. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used for studying structural interaction of nano silicon carbide (SiC) with chitosan. The morphology of chitosan/SiC nanocomposites was investigated by field emission scanning electron microscope (FESEM), and high resolution transmission electron microscope (HRTEM). The thermal stability of chitosan was substantially increased due to incorporation of stable silicon carbide nanopowder. The oxygen permeability of chitosan/SiC nanocomposites was reduced by three folds as compared to the virgin chitosan. The chemical resistance properties of chitosan were enhanced due to the incorporation of nano SiC. The biodegradability was investigated using sludge water. The tensile strength of chitosan/SiC nanocomposites was increased with increasing percentage of SiC. The substantial reduction in oxygen barrier properties in combination with increased thermal stability, tensile strength and chemical resistance properties; the synthesized nanocomposite may be suitable for packaging applications.