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Synthesis and characterization of polysiloxane compound as precursor of silicon dioxide

Danlami, Shehu Isah (2015) Synthesis and characterization of polysiloxane compound as precursor of silicon dioxide. Masters thesis, Universiti Tun Hussein Onn Malaysia.

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Abstract

Polymethylvinylsiloxane . (PMVS) was successfully synthesized by prehydrolysislcondensation of methylvinydichlorosilane (MVDCS) and dimethyldichlorosilane (DMDCS) followed by catalyzed equilibrium copolymerization with sulphuric acid (H2S04) and dibutyltin dilaurate (DBTDL). Then PMVS was photochemically converted to silicon dioxide films by UVIOzone exposure at room temperature in the presence of atmospheric oxygen. All procedures in the experiment were performed under ambient condition. The PMVS samples were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (13c and 2 9 ~NiM R), thermal properties by Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). The results obtained from DSC were 7.5 "C and 33 o C indicating that the polymethylviny'lsiloxane samples have low glass transition temperature (T,) while TGA result showed low thermal decomposition temperatures at 50 OC and 110 "C with low residue yields as a result of oxidation or degradation of methyllvinyl groups. The thin film was then characterized by FESEM and XRD for its surface morphology characteristic and by ATR-FTER spectrometry for its molecular change investigation. It was observed that SiOz film was significantly changed at 30 minutes of UVIozone exposure while increased in the time of exposure made the film surface smoother which enhanced its chemical properties. ATR-FTIR spectra of wavelength around 960 cm-', 1408 cm-I and 1598 cm-' correspond to vinyl group totally disappeared under the UVIozone exposure whereas those at around 791 -795 cm-', 1258- 1260 cm", and 2962-2963 cm-' which correspond to methyl group have not been significantly changed. From the XRD, SiOz film was found to be amorphous in nature while from UV-Visible, the unmodified PVMS absorbed UV radiation at 230 nm and upon increasing the UVIozone exposure time, the peak extends to a wavelength of 300 nrn.

Item Type: Thesis (Masters)
Subjects: Q Science > QC Physics
Depositing User: Normajihan Abd. Rahman
Date Deposited: 17 May 2016 07:19
Last Modified: 17 May 2016 07:19
URI: http://eprints.uthm.edu.my/id/eprint/8023
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