The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite

MWCNT have a unique electrical properties, thermal conductivity which is higher than diamond and a good mechanical properties where strength and stiffness exceed any other current materials However, poor dispersibility and interfacial adhesion of MWCNT in polymer matrix presents a considerable chal...

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Main Author:	Mazlan, Norkhairunnisa
Format:	Thesis
Language:	English
Published:	2012
Subjects:	TA404 Composite materials
Online Access:	http://eprints.usm.my/41136/1/NORKHAIRUNNISA_BINTI_MAZLAN_24_Pages.pdf
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spelling	my-usm-ep.411362018-07-23T08:33:42Z The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite 2012 Mazlan, Norkhairunnisa TA404 Composite materials MWCNT have a unique electrical properties, thermal conductivity which is higher than diamond and a good mechanical properties where strength and stiffness exceed any other current materials However, poor dispersibility and interfacial adhesion of MWCNT in polymer matrix presents a considerable challenge in developing nanocomposite with good properties. Oxidation treatment was done on MWCNT as to improve the dispersion and interfacial adhesion between the nanotubes and PDMS. The oxidation treatments of MWCNT were carried out by oxidizing using either single acid (HNO3) or mixture of acids (HNO3/H2SO4) at 3:1 ratio. The treatments were done for different period of time (3 and 6 hours) and temperature (80°C and 140°C). FTIR and XPS analysis showed the presence of various functional groups such as C-O, C=O and COOH. The O/C ratio increased from 0.17 for untreated MWCNT to 0.56 for oxidized MWCNT. Acid bes titration showed increase in concentration of acid groups about 159%. The oxidation affects the tubes more significantly when the temperature and time increased to 140°C and 6 hours respectively as the ID/IG ratio increased from 0.19 to 0.83 and reduction in thermal stability. The presence of functional groups formed electrical double layer on the MWCNT surface and thus, gave good dispersibility in water. This layer also overcome the strong van der Waals force within the nanotubes and reduced agglomeration. The presence of defects and catalysts were also observed by TEM. For PDMS filled with MWCNT oxidized in HNO3 at 80°C for 3 and 6 hours, the tensile strength increased to 5.06 MPa, while thermal and electrical conductivity slightly increased for approximately to 24% and 42%, respectively over the untreated MWCNT/PDMS nanocomposites. However, for PDMS filled with MWCNT oxidized at 80°C for 6 hours in acid mixture, the thermal and electrical conductivities were slightly decreased to 0.19 W/mK and -4.62 Log/Scm-1. Decrease in properties was more significant for PDMS filled with MWCNT oxidized at 140°C for 6 hours as the Tg value decreased for 9°C compared PDMS reinforced with MWCNT oxidized at 80°C for 6 hours, in which its Tg was approximately -35°C. Aggressive oxidation treatment reduces the capability of MWCNT to form good interfacial interaction with the PDMS matrix. However, this type of MCWNT was suitable to be used to increase the plasticity of the polymer matrix. 2012 Thesis http://eprints.usm.my/41136/ http://eprints.usm.my/41136/1/NORKHAIRUNNISA_BINTI_MAZLAN_24_Pages.pdf application/pdf en public phd doctoral Universiti Sains Malaysia Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral
institution	Universiti Sains Malaysia
collection	USM Institutional Repository
language	English
topic	TA404 Composite materials
spellingShingle	TA404 Composite materials Mazlan, Norkhairunnisa The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite
description	MWCNT have a unique electrical properties, thermal conductivity which is higher than diamond and a good mechanical properties where strength and stiffness exceed any other current materials However, poor dispersibility and interfacial adhesion of MWCNT in polymer matrix presents a considerable challenge in developing nanocomposite with good properties. Oxidation treatment was done on MWCNT as to improve the dispersion and interfacial adhesion between the nanotubes and PDMS. The oxidation treatments of MWCNT were carried out by oxidizing using either single acid (HNO3) or mixture of acids (HNO3/H2SO4) at 3:1 ratio. The treatments were done for different period of time (3 and 6 hours) and temperature (80°C and 140°C). FTIR and XPS analysis showed the presence of various functional groups such as C-O, C=O and COOH. The O/C ratio increased from 0.17 for untreated MWCNT to 0.56 for oxidized MWCNT. Acid bes titration showed increase in concentration of acid groups about 159%. The oxidation affects the tubes more significantly when the temperature and time increased to 140°C and 6 hours respectively as the ID/IG ratio increased from 0.19 to 0.83 and reduction in thermal stability. The presence of functional groups formed electrical double layer on the MWCNT surface and thus, gave good dispersibility in water. This layer also overcome the strong van der Waals force within the nanotubes and reduced agglomeration. The presence of defects and catalysts were also observed by TEM. For PDMS filled with MWCNT oxidized in HNO3 at 80°C for 3 and 6 hours, the tensile strength increased to 5.06 MPa, while thermal and electrical conductivity slightly increased for approximately to 24% and 42%, respectively over the untreated MWCNT/PDMS nanocomposites. However, for PDMS filled with MWCNT oxidized at 80°C for 6 hours in acid mixture, the thermal and electrical conductivities were slightly decreased to 0.19 W/mK and -4.62 Log/Scm-1. Decrease in properties was more significant for PDMS filled with MWCNT oxidized at 140°C for 6 hours as the Tg value decreased for 9°C compared PDMS reinforced with MWCNT oxidized at 80°C for 6 hours, in which its Tg was approximately -35°C. Aggressive oxidation treatment reduces the capability of MWCNT to form good interfacial interaction with the PDMS matrix. However, this type of MCWNT was suitable to be used to increase the plasticity of the polymer matrix.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Mazlan, Norkhairunnisa
author_facet	Mazlan, Norkhairunnisa
author_sort	Mazlan, Norkhairunnisa
title	The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite
title_short	The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite
title_full	The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite
title_fullStr	The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite
title_full_unstemmed	The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite
title_sort	effect of oxidation treatment of mwcnt on the properties of pdms nanocomposite
granting_institution	Universiti Sains Malaysia
granting_department	Pusat Pengajian Kejuruteraan Bahan dan Sumber Mineral
publishDate	2012
url	http://eprints.usm.my/41136/1/NORKHAIRUNNISA_BINTI_MAZLAN_24_Pages.pdf
_version_	1747820880952557568

The Effect Of Oxidation Treatment Of Mwcnt On The Properties Of Pdms Nanocomposite

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