Studies that involve natural fiber orientation in a matrix were mostly based on regulating shear forces during mixing of fiber and matrix. This study attempts to propose a novel technique for orientating natural fibers like cellulose in a viscous polymer matrix such as polylactic acid (PLA) by applying the concepts of magnetism. Orientation of cellulose fibers in a PLA was achieved by modifying the cellulose fibers with a ferromagnetic entity and subjecting to a magnetic field. Chemically modified cellulose fibers (CLF) were oriented in dilute polylactic acid by subjecting the fiber and matrix to a magnetic field of ≈ 4T (Tesla). CLF and Microcrystalline cellulose (MCC) were oxidized with Hydrogen peroxide and further reacted with activated Ferrous sulphate heptahydrate (FeSO4.7H2O) in order to form Cellulose-Fe complexes. Chemically modified CLF was characterized by spectroscopic, thermal and morphological methods. The results from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR spectroscopy) agree that coordination bonds were formed between deprotonated and/or oxidized hydroxyl groups of cellulose and Fe2+ ions. Powder X-ray diffraction (PXRD) was used to compare the crystallinity of unmodified and modified samples of CLF. Thermal properties of modified cellulose were studied using thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). Scanning electron microscopy (SEM) results showed that there was minimal morphological change occurred to cellulose after treatment. It was also observed that the electrical conductivity of cellulose modified with Fe 2+ was higher than that of unmodified samples. The modified CLF was then mixed with polylactic acid diluted with dichloromethane and the fibers in the matrix suspension were subjected to a magnetic field of ≈ 4T. The suspension was allowed to solvent cast inside a glass vial in the magnetic field. Morphological examination of the fiber matrix composites using confocal microscopy showed that CLF were successfully oriented along the flux direction of the magnetic field.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/29883 |
| Date | 31 August 2011 |
| Creators | Sundar, Smith |
| Contributors | Sain, Mohini |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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