Effects of pressure and thickness on elastic and dielectric properties of chitosan

This dissertation describes the effect of pressure on the elastic properties of chitosan and also the effect of thickness and pressure on electrical properties of chitosan. The powdered chitosan is being pressed into pellets and the elastic and electrical properties were studied. The experimental in...

Full description

Saved in:

Bibliographic Details
Main Author:	Mohd Hashim, Nurul Hazwani
Format:	Thesis
Language:	English
Published:	2012
Subjects:	Chitosan - Electric properties Chitosan - Elastic properties
Online Access:	http://psasir.upm.edu.my/id/eprint/32014/1/FS%202012%2049R.pdf
Tags:	Add Tag No Tags, Be the first to tag this record!

id	my-upm-ir.32014
record_format	uketd_dc
spelling	my-upm-ir.320142015-01-23T09:54:46Z Effects of pressure and thickness on elastic and dielectric properties of chitosan 2012-01 Mohd Hashim, Nurul Hazwani This dissertation describes the effect of pressure on the elastic properties of chitosan and also the effect of thickness and pressure on electrical properties of chitosan. The powdered chitosan is being pressed into pellets and the elastic and electrical properties were studied. The experimental investigation was divided into two categories. The minor experimental work, which provides supportive evidence to elastic and electrical properties, consists of work on x-ray diffraction and FTIR. The main experiments consist of work on ultrasonic and electrical measurements. The electrical measurements were measured at low frequencies from 10-2 to 104 Hz while ultrasonic properties were determined with MATEC 8000 at 5MHz resonating frequency and at room temperature. The semicrystalline structure of the chitosan sample was evident by the XRD spectrum. Ultrasonic measurement is used as a non-destructive testing (NDT) technique in analyzing the physical of liquid and solid material. NDT is important because the properties of the sample can be tested without destroying or changing the physical properties of the sample. The elastic moduli, longitudinal modulus (L), shear modulus (G), Young’s modulus (E), bulk modulus (K) and Poisson’s ratio increase with increasing of pressure from 2.0 to 6.0 tonne. The large difference between L and G due to the volume effects shows that the materials formed are easier to bend than to be elongated. Electrical measurement of chitosan shows that sample with 4 mm thickness gives the highest value of ε’(ω) ~ 430 compared to 2 mm sample ε’(ω) ~ 140. And for chitosan pellets with different pressure, it can be observed that sample with 2.0 tonne pressed pressure gives the highest value of ε’(ω) ~ 429 compared to 6.0 tonne sample ε’(ω) ~ 229. The dielectric graphs were then normalized into a master curve and fit using the universal law to obtain the properties and mechanism that took part, with the parameters involved such as p, n and α. The entire fitted graph showed that chitosan consisted of quasi-dc and also dipolar mechanism. In complex impedance, the grain boundary effect that appears as a semicircle at low frequency is bigger than the high frequency bulk semicircle. There is no overlapping of peaks in the modulus and impedance plot which suggested that this sample is a long-range and localized relaxation.The activation energies obtained from the master plot, impedance and modulus spectroscopy studies on chitosan pellets with different pressure and thickness reveals the defect relaxation nature. Chitosan - Electric properties Chitosan - Elastic properties 2012-01 Thesis http://psasir.upm.edu.my/id/eprint/32014/ http://psasir.upm.edu.my/id/eprint/32014/1/FS%202012%2049R.pdf application/pdf en public masters Universiti Putra Malaysia Chitosan - Electric properties Chitosan - Elastic properties Faculty of Science
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English
topic	Chitosan - Electric properties Chitosan - Elastic properties
spellingShingle	Chitosan - Electric properties Chitosan - Elastic properties Mohd Hashim, Nurul Hazwani Effects of pressure and thickness on elastic and dielectric properties of chitosan
description	This dissertation describes the effect of pressure on the elastic properties of chitosan and also the effect of thickness and pressure on electrical properties of chitosan. The powdered chitosan is being pressed into pellets and the elastic and electrical properties were studied. The experimental investigation was divided into two categories. The minor experimental work, which provides supportive evidence to elastic and electrical properties, consists of work on x-ray diffraction and FTIR. The main experiments consist of work on ultrasonic and electrical measurements. The electrical measurements were measured at low frequencies from 10-2 to 104 Hz while ultrasonic properties were determined with MATEC 8000 at 5MHz resonating frequency and at room temperature. The semicrystalline structure of the chitosan sample was evident by the XRD spectrum. Ultrasonic measurement is used as a non-destructive testing (NDT) technique in analyzing the physical of liquid and solid material. NDT is important because the properties of the sample can be tested without destroying or changing the physical properties of the sample. The elastic moduli, longitudinal modulus (L), shear modulus (G), Young’s modulus (E), bulk modulus (K) and Poisson’s ratio increase with increasing of pressure from 2.0 to 6.0 tonne. The large difference between L and G due to the volume effects shows that the materials formed are easier to bend than to be elongated. Electrical measurement of chitosan shows that sample with 4 mm thickness gives the highest value of ε’(ω) ~ 430 compared to 2 mm sample ε’(ω) ~ 140. And for chitosan pellets with different pressure, it can be observed that sample with 2.0 tonne pressed pressure gives the highest value of ε’(ω) ~ 429 compared to 6.0 tonne sample ε’(ω) ~ 229. The dielectric graphs were then normalized into a master curve and fit using the universal law to obtain the properties and mechanism that took part, with the parameters involved such as p, n and α. The entire fitted graph showed that chitosan consisted of quasi-dc and also dipolar mechanism. In complex impedance, the grain boundary effect that appears as a semicircle at low frequency is bigger than the high frequency bulk semicircle. There is no overlapping of peaks in the modulus and impedance plot which suggested that this sample is a long-range and localized relaxation.The activation energies obtained from the master plot, impedance and modulus spectroscopy studies on chitosan pellets with different pressure and thickness reveals the defect relaxation nature.
format	Thesis
qualification_level	Master's degree
author	Mohd Hashim, Nurul Hazwani
author_facet	Mohd Hashim, Nurul Hazwani
author_sort	Mohd Hashim, Nurul Hazwani
title	Effects of pressure and thickness on elastic and dielectric properties of chitosan
title_short	Effects of pressure and thickness on elastic and dielectric properties of chitosan
title_full	Effects of pressure and thickness on elastic and dielectric properties of chitosan
title_fullStr	Effects of pressure and thickness on elastic and dielectric properties of chitosan
title_full_unstemmed	Effects of pressure and thickness on elastic and dielectric properties of chitosan
title_sort	effects of pressure and thickness on elastic and dielectric properties of chitosan
granting_institution	Universiti Putra Malaysia
granting_department	Faculty of Science
publishDate	2012
url	http://psasir.upm.edu.my/id/eprint/32014/1/FS%202012%2049R.pdf
_version_	1747811640743559168

Effects of pressure and thickness on elastic and dielectric properties of chitosan

Similar Items