Runcy Wilson

Performance evaluation of polysulfone/graphene nanocomposites

Abstract The present work focuses on the performance and properties of organomodified graphene nanoplatelet filled polysulfone nanocomposites prepared by solution casting. Morphology of the nanocomposites was investigated using atomic force microscopy and transmission electron microscopy. Contact angle measurements showed significantly increased hydrophobicity of the nanocomposites relative to the neat polymer. Mechanical properties of the nanocomposites showed marked improvement at low graphene loadings. Thermal properties measured using thermogravimetric analysis showed that the incorporation of graphene increased the thermal stability and the char yield of the nanocomposites. After immersing the samples in various solvents, the changes in weight and mechanical property were evaluated and the aging performance was found to be improved. The prepared polysulfone nanocomposites with desired hydrophobic, thermal, mechanical and barrier properties are usable for high performance applications.

CHAPTER 21:Rheological Behaviour of Natural Rubber Based Composites and Nanocomposites

Rheological properties have important implications in many and diverse applications in the area of natural rubber composites. The measurement of rheological properties of any polymeric material in the molten state is crucial in order to gain a fundamental understanding of the processability of that material. This is because rheological behaviour is strongly influenced by the material structure and the interfacial characteristics. In the manufacture of polymeric objects, most of the shaping is carried out in the molten state, as it is an important part of the physical property development. The viscoelastic character of polymer melts reflects the entangled microstructure and plays an important role in property development and in flow stability. This chapter is intended first to provide an overview of the rheology of natural rubber composites and nanocomposites. The chapter also provides a collection of knowledge based in the scientific literature and the developments involving the rheological properties of polymers, the structure and morphology of molten polymer blends vividly showing that the field of polymer technology rapidly expands at ever higher rates.

Liquid Transport Characteristics in Polymeric Systems: An Introduction

Abstract The passage of small molecules through polymers and their composites have been the subject of intensive research since 1975. A better understanding of the nature of the polymer and the influence of various fillers on transport phenomena is highly important to achieve significant improvement in the areas of protective coatings, membrane separation processes, and packaging industry. A combination of improved economics and better technology has resulted in a wide range of products in the commercial use of membranes. This chapter gives a brief overview of the factors governing the transport of small molecules through interpenetrating polymer networks, polymeric networks, their blends, and composites.

Green and facile approach to prepare polypropylene/in situ reduced graphene oxide nanocomposites with excellent electromagnetic interference shielding properties

The present work discloses the admirable electromagnetic interference shielding effectiveness (∼50 dB at X and Ku Bands) realized by means of excellent dispersion state of reduced graphene oxide (rGO) in a polypropylene (PP) matrix, even at high concentrations (20 wt%). This was achieved by means of a latex method (polymer matrix; here PP in the aqueous emulsion state) combined with in situ reduction of graphene oxide using L-ascorbic acid as the reducing agent (green approach). A probable reaction mechanism between the maleic acid anhydride part of the PP matrix with the remaining –OH groups of rGO which may further assist in the better dispersion of graphene is also suggested. The prepared PP/rGO nanocomposites showed a percolation threshold in between that of 1.5 and 3 wt% rGO content. The microcapacitor and the conductive pathway formation in the system are explained nicely with the help of a schematic diagram. The electromagnetic interference shielding effectiveness (EMI SE) of 50 and 48 dB achieved for the X and Ku-bands for the 20 wt% rGO filled sample is one of the best among current works based on GO as the filler. The thermal stability of the samples increased marginally due to the addition of thermally stable rGO. The crystallization temperature increased with increasing rGO content owing to its good nucleating ability, whereas the melting characteristics shifted from double to single melting behavior possibly due to the ability of rGO to explicitly nucleate a particular polymorph of PP. A simple, cost efficient, green and promising approach to prepare non-polar polymer/graphene nanocomposites with a good dispersion state of graphene and excellent properties is reported in the present work.

Polymer membranes reinforced with carbon-based nanomaterials for water purification

Abstract Advancements in water purification techniques are an important area of research nowadays owing to the swiftly growing demand for fresh water. The demand for fresh water is going to grow further in the coming decades, hence the need for cost effective, environmentally friendly techniques for water purification. Current technologies include membrane processes ranging from reverse osmosis, membrane distillation, pervoparation, etc., for drinking water management. The current polymer membranes being used in water purification techniques have several disadvantages related to their mechanical and thermal stability. This article brings together the current applications of carbon-based nanomaterials in water purification techniques owing to their exceptional mechanical, thermal, and antibacterial properties, and high thermal stability.

Ultraviolet Spectroscopy: A Facile Approach for the Characterization of Nanomaterials

Abstract Ultraviolet (UV)–visible spectroscopy is a promising technique that can be used to characterize nanomaterials with light, which is absorbed and scattered by a sample. The properties of materials change dramatically when their size is reduced to the nanometer range, but the characterization of these nanomaterials is not a simple task. In UV spectroscopy the magnitude, peak wavelength, and spectral bandwidth associated with a nanoparticle are reliant on the particles size, shape, and material composition. The precise control of nanoparticle size, size distribution, and dispersion at the nanolevel is very important in the specific usage of these materials. The basics of and the important areas related to UV characterization of nanomaterials are discussed in this chapter.

CHAPTER 16:Nanocellulose: A Novel Support for Water Purification

Water pollution is a serious environmental and public concern all over the world. Many toxic metals (e.g., lead and cadmium) even at trace levels are believed to have adverse effects on human health. Thus, it is important to develop efficient technologies for enhanced removal of toxic metal ions from contaminated waters. Various technologies have been developed for the decontamination of water. Nanocellulose has attracted a great deal of interest as a source of nanometer-sized materials because of their biodegradability, easy availability, and the related characteristics, such as a very large surface-to-volume ratio and outstanding mechanical properties. This article assembles the current applications of nanocellulose in the environment, namely as an adsorbent for heavy metals, water purification, antimicrobial and catalytic activities, and a reinforcement for biodegradable materials. Water pollutant remediation by catalytic decomposition of organic pollutants is a growing application of nanocellulose-based nanocomposites.