1. Formation of Silicon oxycarbide whiskers on the surface of PDMS (sylgard 184)/functional carbon nanotubes nanocomposite
Saman Azharia, M.N. Hamidona,b, Kure Nicodemusb, Intan Halina Hasana, Kamilu Iman Usmana, Rosiah Osmana
aInstitute of Advanced Technology (ITMA), Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
bDepartment of Electrical and Electronics, Faculty of Engineering, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
*Corresponding Autor’s
Abstract: In this work we report the formation of Silicon oxycarbide whiskers on the surface of PDMS/FMWCNTs nanocomposite. Crystal site is observable by FESEM. These formation may be due to hydrosylilation process although FTIR results indicate the presence of C-O group on the surface of PDMS nanocomposite, which can be the cause of these formations through aging process. INTRODUCTION Finding an alternative method to synthesize Silicon oxycarbide (SiOC) has attracted a lot of attentions; synthesis of SiOC crystalline materials from polymer precursors has been suggested to be more efficient, because of the low processing pressure and temperature [1,2]. Herein we report, low yield formation of silicon oxycarbide (SiOC) whiskers on the surface of polydimethylsiloxane (PDMS)/carbon nanotubes (CNTs) nanocomposite. MATERIALS AND METHODS Commercial multiwall carbon nanotubes (MWCNTs) produced by catalytic decomposition (L.MWNTs-2040, length=5-15 μm, diameter=20-40 nm, Shenzhen Nano-technologies Port Co. Ltd., Shenzhen, China); polydimethylsiloxane (PDMS) (SYLGARD 184); THF (Sigma Aldrich); 30% hydrogen peroxide and 98% sulfuric acid (R&M Chemicals) were used for this work. RESULTS AND DISCUSSION The presence of the defect sites on the surface of the MWCNTs may be the reason behind the formation of SiOC whiskers. Although it has been suggested that this formation could have occurred due to aging process of PDMS in the presence of MWCNTs; it does not eliminate our assumption regarding the defect site. Even though the yield is low it is possible to observe the increase in crystalline sites by increasing the amount of MWCNTs. Since this effect happens on the surface of nanocomposite we can assume that this is due to the Dimethyl vinylated and trimethylated silica which are present in PDMS as surface modifier. Formation of SiOC on the surface of PDMS/FMWCNTs nanocomposite suggests that hydrosilylation might have occurred on both base and cure materials which contain surface modifier while removing the hydrogen atoms from FMWCNTs which results in attachment of C-O to silicon and forming SiOC whiskers. FESEM result exhibits a crystalline whisker of SiOC. FTIR result indicates the presence of C-O (1714 cm-1) on the surface of nanocomposite while the PDMS surface does not contain any C-O group.
Hydrosilylation
FESEM Image of nanocomposite surface
FTIR of PDMS
EDS result of formation
FTIR of Nanocomposite
CONCLUSIONS
In this work we reported the formation of Silicon oxycarbide whiskers on the surface of PDMS/FMWCNTs nanocomposite. Microscopic observation indicate that by increase in weight percentage of FMWCNTs the yield of SiOC increases. These formation may be due to hydrosylilation process of PDMS elastomer although FTIR results indicate the presence of C-O group on the surface of PDMS nanocomposite, which can be the cause of these formations through sedimentation and aging process. It is possible to develope this method for synthesizing high yeild of SiOC at low pressure and temprature.
 REFERENCES
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Microscopic images of formation
Photo
(Project leader)
Saman Azhari
GS36671