Gejo George

Dynamic mechanical and rheological properties of nitrile rubber nanocomposites based on TiO2, Ca3(PO4)2 and layered silicate

The viscoelastic properties such as damping behaviour, storage and loss modulus, etc. of polymer composites depend on matrix filler interaction, crystallinity and the extent of crosslinking. It was observed that the storage modulus of the composites increased with the addition of filler due to the enhancement in stiffness of the material. The damping behaviour was found to decrease as a function of filler loading and this was attributed to the restricted movement of the polymer segments. The higher surface area to volume ratio factor of the layered silicate resulted in the better interaction between the polymer matrix and the filler, which resulted in the change in glass transition temperature. The flow properties were studied with special reference to filler loading of different fillers at a specified temperature. It was observed that complex viscosity of filled systems is higher than that of unfilled system. Among the fillers, layered silicate filled systems showed higher viscosity in comparison with calcium phosphate and titanium dioxide fillers.

Novel eco-friendly commingled polypropylene/banana fiber composite: studies on thermal and mechanical properties

The thermal and mechanical properties of locally available bio-extracted banana fiber reinforced polypropylene commingled composite systems were studied. An entirely new method was adopted for the extraction of banana fiber, which is through an anaerobic process. The thermal properties of the commingled composite (both treated and untreated) were analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed an improved thermal stability for the treated composites. A noticeable increase is observed in the hardness and tensile properties of the treated samples compared to the untreated ones while a decrease is observed for the impact properties of the treated samples. The surface morphology and fiber treatments were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy.

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.

Jute yarn as reinforcement for polypropylene based commingled eco-composites: Effect of fibre content and chemical modifications on accelerated ageing and tear properties

Bidirectional PP/jute yarn eco-composites were fabricated via environment friendly commingling technique and its long term durability/life time was monitored as an effect of accelerated solar ageing on its mechanical properties (tensile & flexural). Accelerated solar ageing promoted the thermal oxidation of PP thus resulting in deterioration of its properties, however; MAPP and KMnO4 treated commingled composites showed much better stability towards thermal oxidation brought about by the solar concentrator, compared to untreated sample and neat polypropylene. This increased resistivity of treated composites (especially MAPP and KMnO4) towards thermal oxidation brought about by the solar concentrator is due to the increased interfacial adhesion between the matrix and jute yarn owing to chemical modifications. The significance of effective stress transfer between the PP matrix and reinforcing jute yarns is evident from the increased tear resistance of PP/jute yarn commingled composites with increasing fibre content and also with different chemical treatments.

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.