Muthu Pannirselvam

Chemically imaging the interaction of acetylated nanocrystalline cellulose (NCC) with a polylactic acid (PLA) polymer matrix

The non-covalent interaction of acetylated nanocrystalline cellulose (AC-NCC) with polylactic acid (PLA) in a composite blend has been studied at the micron scale by synchrotron Fourier transform infrared (FTIR) microspectroscopy. Microtomed sections of AC-NCC in PLA showed strong, localized carbonyl stretching (νC=O) absorbance characteristic of the cellulose acetylation, and this was observed on the surface of larger aggregated AC-NCC particles. A shift in the νC=O IR absorption peak of AC-NCC in PLA, relative to unblended AC-NCC was observed, which is indicative of an intermolecular interaction between AC-NCC and PLA matrix. Acetylation can therefore potentially improve the performance of the composite by enabling linkages between carbonyl groups, helping to establish a good stress transfer between the fiber and the matrix. This could in turn lead to a material with high yield elastic modulus. This is the first reported chemical imaging of acetylated nanocrystalline cellulose-based composite materials using synchrotron FTIR microspectroscopy.

Intercalation of Montmorillonite by Interlayer Adsorption and Complex Formation

Clays are essentially composed of crystalline particles of one or more members of a small group of minerals. The ability of clays to intercalate certain organic substances has been known for a very long time. There is a scope in these clay structures for isomorphous replacement, that is, for substitution of Na+ by cations of similar size but usually of lower valency. This research aims at identifying suitable additives for pretreatment of clay and determining the effect of different classes of compounds (intercalants) on the d-spacing expansion of clay layers. This paper addresses a different approach to ion exchange for treatment of sodium montmorillonite, with different functional groups: aldehyde, ether, alcohol, glycol, and stearates. The results were compared with commercially available clays, Cloisite 25A and Cloisite 30B (Southern Clay Products), which are montmorillonite (MMT) clays intercalated with quaternary ammonium salts. The d-spacing increment in this research was consistent with the d-spacing achieved in commercially available clays. Future research will be to utilize the treated clay to produce polymer composites.

Potential Use of Biochar from Sugarcane Bagasse for Treatment of Textile Wastewater

The use of activated carbon for the treatment of wastewater from textile industries is integral to the production of reusable water. Despite its abundance in countries where textiles are produced and the apparent suitability of sugarcane bagasse (SCB) as a feedstock for the production of activated carbon, this material is not used commercially as it is uneconomic to produce when compared to other biomass sources. This chapter reports on the chemical pretreatment of SCB as a means to increase the production of biochar from SCB. The thermal degradation kinetics of bagasse was examined by thermal gravimetric analysis (TGA). Furthermore, Fourier transfer infrared (FTIR) spectroscopy of evolved gases was recorded to better understand the mechanism by which the treatment process affects the degradation of the SCB during pyrolysis. Two chemicals were used as chemical additives—ammonium sulphate (AS) and diammonium phosphate (DAP). These were added to bagasse as solutions at different concentrations ranging from 0.01 to 1 M prior to pyrolysis. It was generally found that the bagasse treated with additives caused mass degradation at lesser temperatures and formed considerably greater yields of biochar than untreated raw bagasse. Greater concentrations of additives improved the char yield significantly but passed through an optimum additive concentration for char yield. It was reasoned that the optimum was caused by a change in reaction mechanism when additive concentrations became high as evidenced by the FTIR spectrum measured—although this mechanism varies with the different additives. The addition of chemical additives to SCB so as to improve char yield may provide a route by which the SCB may be an economically attractive source of biochar.

Nanofiltration of Dye Bath Towards Zero Liquid Discharge: A Technical and Economic Evaluation

A dye bath effluent is the most resource-rich stream in a dye house in the textile industry with almost all salts used and 0–40% of unfixed dyes, and 10% of water in a wet process. A lot of effort has been made to breakdown dyes physically, chemically and biologically and mainly for meeting the local government discharge standard, however, salts in the dye bath are unchanged and are simply diluted and discharged to the environment. Both salts and dyes are valuable commodities. If they are recovered, less resources will be wasted and less damage will be done to the environment. This is beneficial to both the industries and the environment. Membrane filtration is an effective tool to separate chemicals according to their sizes and surface charges without altering their properties. In this chapter, we reviewed the development of Nanofiltration membrane technology (NF) in terms of lower salt rejection and membrane fouling and proposed the mechanisms of membrane pore enlargement during separating salts from dye in a dyebath for recovery, recycling and reuse. We also mentioned the industries that use dyes and pigments in their daily operations. We have concluded that membrane swelling/pore enlargement remains a challenge on NF application.

Influence of the concentration of chemical elements in the age estimation of polymeric insulation

The study of the lifetime performance of polymeric insulator is often based on incomplete data. Researchers face challenges of not having long observation time to gather complete lifetime data in order to make prediction with certainty. In this paper, we are proposing to use the best fitting polynomial interpolation approach to determine the lifetime model and extrapolate information towards the age of polymeric insulators. To gather the information such as the change of concentration of chemical element of polymeric insulation due to multiple stress conditions, high temperature vulcanized (HTV) silicone rubber specimens were subjected to accelerated degradation using an Accelerated Weathering Tester (QUV). Each specimen was subjected to accelerated aging cycle in accordance to ASTM G154 cycle 4 for a total of 3000 hours. The aging cycle goes through a cycle of 70 °C and ultraviolet exposure at irradiation intensity of 1.55 W/m2 for eight hours followed by four hour condensation at 50 °C. Chemical element concentrations such as Carbon, Oxygen, Silicon and Aluminum were obtained and evaluated using a Scanning Electron Microscope (SEM) with energy dispersive x-ray (EDX). The concentrations of chemical elements are analyzed using polynomial interpolation method of multiple orders. First order to fifth order polynomial interpolation methods are investigated to determine the best fitting curve without significance divergence from the actual value or true value. The interpolation curve is used to estimate the age of an unknown aged sample. This investigation has revealed a novel method for determining a model that could describe the lifetime of polymeric insulators and extrapolation method for estimating the age for polymer insulator.

Thermal Behaviour of Hardwood and Softwood Composites

In the present study, the thermongravimetric analysis (TGA) of laboratory hardwood and softwood particleboard was studied. The TGA showed that both hardwood and softwood have similar thermal behaviour at the same peak temperature. However, softwood is concluded to have higher fire retardancy as more char formation happened in softwood. A further study was carried out to compare the thermal behaviour of laboratory manufactured boards with the commercial grade boards. Superior thermal stability of commercial particleboard had confirmed its effective crosslinking and wood-resin adhesion.