Sudip Ray

The Potential Use of Polymer-Clay Nanocomposites in Food Packaging

With todays advancement in nanotechnology, Polymer-Clay Nanocomposite has emerged as a novel food packaging material due to its several benefits such as enhanced mechanical, thermal and barrier properties. This article discusses the potential use of these polymer composites as novel food packaging materials with emphasis on preparation, characterization, properties, recent developments and future prospects.

Evaluation of gallic acid loaded zein sub-micron electrospun fibre mats as novel active packaging materials

The applicability of gallic acid loaded zein (Ze-GA) electrospun fibre mats towards potential active food packaging material was evaluated. The surface chemistry of the electrospun fibre mats was determined using X-ray photon spectroscopy (XPS). The electrospun fibre mats showed low water activity and whitish colour. Thermogravimetric analysis (TGA) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy revealed the stability of the fibre mats over time. The Ze-GA fibre mats displayed similar rapid release profiles, with Ze-GA 20% exhibiting the fastest release rate in water as compared to the others. Gallic acid diffuses from the electrospun fibres in a Fickian diffusion manner and the data obtained exhibited a better fit to Higuchi model. L929 fibroblast cells were cultured on the electrospun fibres to demonstrate the absence of cytotoxicity. Overall, the Ze-GA fibre mats demonstrated antibacterial activity and properties consistent with those considered desirable for active packaging material in the food industry.

Electrospun Functionalized Polyaniline Copolymer‐Based Nanofibers with Potential Application in Tissue Engineering

Nanofibrous blends of HCl-doped poly(aniline-co-3-aminobenzoic acid) (3ABAPANI) copolymer and poly(lactic acid) (PLA) were fabricated by electrospinning solutions of the polymers, in varying relative proportions, in dimethyl sulfoxide/tetrahydrofuran mixture. The morphology, mechanical and electrical properties of the nanofibers were characterized and an assessment of their bioactivity performed. To assess cell morphology and biocompatibility, pure PLA and 3ABAPANI-PLA nanofibrous mats were deposited in the form of three-dimensional networks with a high degree of connectivity, on glass substrates, and their ability to promote proliferation of COS-1 fibroblast cells was determined. The nanofibrous electrospun 3ABAPANI-PLA blends gave enhanced cell growth, potent antimicrobial capability against Staphylococcus aureus and electrical conductivity. This new class of nanofibrous blends can potentially be employed as tissue engineering scaffolds, and in particular have showed promise as the basis of a new generation of functional wound dressings that may eliminate deficiencies of currently available antimicrobial dressings.

Advances in Polymer-Filler Composites: Macro to Nano

It has been long known that polymers can be mixed with clay minerals, however, the ideas of microcomposites have been expanded recently to a new and emerging class of clay-filled polymers, called Polymer-Clay Nanocomposites (PCN), which has experienced the real breakthrough early in the past decade only. This is a novel class of composites that are particle-filled polymers for which at least one dimension of the dispersed particles is in the nanometer range with very low filler loading (usually 2–6% by weight). Due to the unique structure, specifically the high aspect ratio of these mineral fillers, the resultant high surface area provides similar reinforcing performance to that of traditional minerals and fibers used in polymers and yet does not increase density, since loading levels are low. Because of the nanometer size of the particles, which is smaller than the wavelength of visible light, the reinforced polymer remains transparent. Other characteristics of these composites include high barrier performance and improved thermal stability, which make these compounds suitable for many applications. This review aims to provide a brief current overview in exploring this new class of polymer composites.

Electrospinning applications from diagnosis to treatment of diabetes

Electrospinning is a facile, yet low cost and reproducible technique that can use both natural and synthetic polymers to address problems in diagnosis and treatment of diabetes. For the diagnosis of diabetes, effective continuous glucose monitoring of the blood glucose level can be achieved by using electrospun glucose biosensors. Electrospun nanofibers confer a high-surface area, micro-porosity, and potential to encapsulate drugs or biomolecules within nanofibers. Even though electrospinning has been used widely there is no review available till now with the applications of electrospinning specifically for the diagnosis and treatment of diabetes. In this critical review, recent advances of electrospinning to optimize the glucose sensing ability and a myriad of diabetic drug delivery techniques via electrospinning are discussed. Future perspectives of biodegradable nanofibers are also discussed in the last section, which highlights the current challenges, innovation and development of novel electrospun nanofibers for theranostics targeted to diabetics.

Grafting of LiAMPS on ethyl cellulose: a route to the fabrication of superior quality polyelectrolyte gels for rechargeable Lithium ion batteries

New types of semi-interpenetrating polymer gel electrolytes with high conductivity as well as strength for use in rechargeable Lithium polymer batteries are synthesized. Single ion conducting polyelectrolyte gels are made by first synthesizing grafted linear chains of Lithium salt of 2-acrylamido-2-methylpropane sulphonic acid on ethyl cellulose (EC) using free radical initiator azobis (cyclohexanecarbonitrile) in dimethyl acetamide solvent, then copolymerizing methyl methacrylate (MMA) and a crosslinking agent ethyleneglycol dimethacrylate to form semi-interpenetrating network. The effect of concentrations of EC and MMA on electrical conductivity and mechanical strength of gels are determined.

Influence of Heat Curing on Structure and Physicochemical Properties of Phenolic Acid Loaded Proteinaceous Electrospun Fibers

Effects of heat treatment on structure and physicochemical properties of zein (Ze) and gallic acid loaded zein (Ze-GA) electrospun fiber mats were investigated. The electrospun fiber mats displayed different surface and physicochemical properties after being heat-cured at 150 °C for 24 h, which were closely related to the initial amount of loaded gallic acid. The gallic acid was released from the Ze-GA fiber mats in a constant manner, but heat curing decreased the rate of release. Heat curing remarkably increased the molecular weight of the Ze and Ze-GA electrospun fiber mats. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis of the fiber mats indicated variations in zein protein secondary structure after heat curing. (13)C solid state NMR (SS-NMR) confirmed the presence of a different chemical environment among the fiber mats. The fabrication of heat-cured zein based electrospun fibers in this study may find applications in the food packaging industry.

Electrospun poly(lactic acid) based conducting nanofibrous networks

Multi-functionalised micro/nanostructures of conducting polymers in neat or blended forms have received much attention because of their unique properties and technological applications in electrical, magnetic and biomedical devices. Biopolymer-based conducting fibrous mats are of special interest for tissue engineering because they not only physically support tissue growth but also are electrically conductive, and thus are able to stimulate specific cell functions or trigger cell responses. They are effective for carrying current in biological environments and can thus be considered for delivering local electrical stimuli at the site of damaged tissue to promote wound healing. Electrospinning is an established way to process polymer solutions or melts into continuous fibres with diameter often in the nanometre range. This process primarily depends on a number of parameters, including the type of polymer, solution viscosity, polarity and surface tension of the solvent, electric field strength and the distance between the spinneret and the collector. The present research has included polyaniline (PANi) as the conducting polymer and poly(L-lactic acid) (PLLA) as the biopolymer. Dodecylbenzene sulphonic acid (DBSA) doped PANi and PLLA have been dissolved in a common solvent (mixtures of chloroform and dimethyl formamide (DMF)), and the solutions successfully electrospun. DMF enhanced the dielectric constant of the solvent, and tetra butyl ammonium bromide (TBAB) was used as an additive to increase the conductivity of the solution. DBSA-doped PANi/PLLA mat exhibits an almost bead-free network of nanofibres that have extraordinarily smooth surface and diameters in the range 75 to 100 nm.

Thermal Degradation of Polymer and Polymer Composites

Abstract While polymeric materials have been used for centuries, it wasn’t until the end of the nineteenth century that polymers were used for commercial purposes. Ever since, due to their unique physical and chemical properties and ease of production, the polymeric materials find applications in the biomedical, civil, electronics, automobile and many other sectors. However, the organic nature of common polymeric substances can cause material instability and even decomposition under various conditions. As a result, the material loses its applicability and may also produce toxic byproducts that could cause health and safety issues and also harm the environment (Unwin et al., 2013). Environmental factors such as heat, humidity, solar UV light, ozone, impurities, mechanical load, chemicals, and microorganisms, individually or in combination, can lead to degradation in polymeric materials. This chapter will primarily focus on heat- or thermal-related degradation of these materials.

Zein-Polyaniline Blends—a Route to Electrically Conductive Biopolymer

Preparation of zein-methanesulfonic acid doped polyaniline (PANI) conductive blends using different approaches is described. Zein-PANI films from homogeneous solutions of the components in 1-methyl-2-pyrrolidinone were made by casting method. In another approach, in situ polymerisation of aniline in the presence of zein or corn gluten meal (CGM) was performed. It was carried out in heterogeneous conditions onto the suspension of zein or CGM and also homogeneously with zein and aniline dissolved in aqueous alcohol. The electrical conductivity of the zein-PANI products was measured. They were also characterised by Fourier Transform Infra Red Spectroscopy, Dynamic Mechanical Thermal Analysis, Gel Permeation Chromatography, X-ray Photoelectron Spectroscopy, Elemental analysis and Scanning Electron Microscopy.