Electrochemical synthesis of poly(methylsilyne), and the effect of silicon-based preceramic polymers on the properties of polypropylene based composites

Eroğlu, Damla
In the first part of this dissertation, poly(methylsilyne) was produced both in small and large-scales. In the small-scale, the aim was to synthesize the polymer by electrochemical polymerization of methyltrichlorosilane at a constant potential of -6 V supplied by batteries, using sodium dodecyl sulfate (SDS) as the supporting electrolyte. The polymer was characterized by 1H-NMR, FTIR, UV-Visible Spectroscopy and GPC in addition to its distinctive yellow color. The yellow color and the 1H-NMR, FTIR, UV-Visible and GPC results proved that poly(methylsilyne) was produced successfully in small-scale. In the second part of the synthesis, the objective was to scale-up the electrochemical synthesis of poly(methylsilyne) while investigating the effects of the parameters like the electrode, solvent and supporting electrolyte types, monomer/solvent ratio and reaction time on the synthesis. Although successful results were obtained in large-scale synthesis with acetonitrile and SDS, the problems with the reproducibility of the synthesis were solved using a system containing 1.2-dimethoxyethane (DME) and tetrabutylammonium perchlorate (TBAP). In the second part of the dissertation, the aim was to prepare polypropylene/silicon-based preceramic polymer blends and to characterize them in terms of flammability, thermal and mechanical properties and morphologies. In order to investigate the effect of the silicon-based preceramic polymers, two different polymers were used: poly(methylsilyne) (PMSy) and allylhydridopolycarbosilane (SMP-10) where the latter was a commercially available silicon carbide precursor. Triphenylphosphate (TPP) and a metal complex were also used in polypropylene based composites to gain a synergy with the silicon containing polymers. The polymer composites were prepared using a twin-screw extruder and molded in an injection molding machine. As a result of the flammability tests, it was seen that in order to achieve a significant decrease in the flammability of polypropylene, at least 20 wt% additive was needed. Furthermore, it was observed that the most significant improvement in flame retardancy was obtained in PP/10SMP/5TPP/5M sample containing 10 wt% SMP-10, 5 wt% TPP and 5 wt% metal complex with a limiting oxygen index (LOI) value of 23.5%. This was explained by the synergy obtained by SMP-10, TPP and the metal complex. With the addition of these silicon containing polymers, thermal properties of the composites increased to a great extent. For the mechanical properties, it was seen that impact strength of the composites significantly increased with the addition of SMP-10, PMSy and TPP.


Silicon-based preceramic polymers and their uses in polymer composites: synthesis, characterization and processing
Dönmez Karadal, Sibel; Bayram, Göknur; Department of Chemical Engineering (2011)
The objectives of this study are to synthesize poly(dimethylsilane) (PDMS) preceramic polymer and to investigate its effect on morphology, flame retardant and mechanical properties of polypropylene (PP) based composites. There are mainly two parts in this thesis. In the first part, PDMS was synthesized by electrochemical polymerization of dichlorodimethylsilane, which was dissolved in 1,2 dimethoxyethane (DME) solvent consisting of tetrabutyl ammonium perchlorate (TBAP), as supporting electrolyte. PDMS was ...
Microwave initiated polymerization of trihalophenyleneoxide and aniline
Levent, Fulya; Kısakürek, Duygu; Toppare, Levent Kamil; Department of Polymer Science and Technology (2011)
The aim of the study is to synthesize poly(dibromophenyleneoxide) and polyaniline separately applying different microwave energies (90-900 watt), water amounts (1-5 ml) and time intervals (2-10 min) and investigate the effects of these parameters on the percent conversion of the polymers. The synthesis of poly(dibromophenyleneoxide) (P), radical ion polymer (RIP) and crosslinked polymer (CLP) were achieved by using tribromophenol (TBP) and Ca(OH)2 via microwave energy in a very short time interval. P and RI...
Electrochemical Synthesis of Poly(methylsilyne) and Investigation of the Effects of Parameters on the Synthesis
EROĞLU PALA, DAMLA; Nur, Yusuf; Bayram, Göknur; Toppare, Levent Kamil (Wiley, 2010-12-05)
This study aims to synthesize poly(methylsilyne) by electrochemical reduction of methyltrichlorosilane at a constant potential of -6 V, while investigating the effects of parameters such as the nature of the electrode, solvent and supporting electrolyte, the monomer/solvent ratio, and the reaction time on the properties of the products. The polymer was characterized by H-1-NMR (Proton Nuclear Magnetic Resonance Spectroscopy), FTIR (Fourier Transform Infrared Spectroscopy), UV-Visible Spectroscopy, and TGA (...
Kinetic studies for the production of tertiary ethers used as gasoline additives
Boz, Nezahat; Doğu, Timur; Department of Chemical Engineering (2004)
In the present study, the kinetics studies for etherification reactions were investigated in detail. In the first phase of present study, different acidic resin catalysts were prepared by the heat treatment of Amberlyst-15 catalysts at 220°C at different durations of time and also by the synthesis of sulfonated styrene divinylbenzene cross-linked resins at different conditions. A linear dependence of reaction rate on hydrogen ion-exchange capacity was in 2M2B+ethanol reaction. However, in the case of 2M1B+e...
Comparison of Efficiency of Two dc-to-ac Converters for Grid Connected Solar Applications
Ertan, Hulusi Bülent; Yilmaz, Arif (2012-05-26)
In this paper; requirements from grid connected photovoltaic (PV) converters are briefly reviewed. Traditional buck-converter, line-frequency transformer topology is taken as reference, which satisfies all of the requirements imposed by standards and the utility. However, this topology employs a bulky transformer. Furthermore, a large electrolytic capacitor is needed in this circuit, which is expensive and also limits the life of the converter. This is not desirable in modern applications where PV module st...
Citation Formats
D. Eroğlu, “Electrochemical synthesis of poly(methylsilyne), and the effect of silicon-based preceramic polymers on the properties of polypropylene based composites,” M.S. - Master of Science, Middle East Technical University, 2008.