Browsing by Author "Seki, Y."

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Oxygen Plasma Treatments of Jute Fibers in Improving the Mechanical Properties of Jute/Hdpe Composites
(Elsevier Science Sa, 2011) Sever, K.; Erden, S.; Gulec, H. A.; Seki, Y.; Sarikanat, M.
The surfaces of jute fabrics have been oxygen plasma treated using low frequency (LF) and radio frequency (RF) plasma systems at different plasma powers (30, 60, and 90 W) for 15 min to improve the mechanical properties of jute fiber/HDPE (high density polyethylene) composites. The effect of oxygen plasma treatment on the functional groups of jute fibers was examined by X-ray photoelectron spectroscopy (XPS) analysis. Effects of oxygen plasma treatments on the mechanical properties of jute fiber/HDPE composites were investigated by means of tensile, flexure, and short-beam shear tests. Surface morphology of the fractured surfaces of composites was observed by using scanning electron microscopy (SEM). When RF plasma system was used, the interlaminar shear strength (ILSS) values of the composites increased with increasing plasma power. Similarly, in LF plasma system, ILSS values showed a tendency to increase at plasma powers of 30 and 60 W. However, increasing of plasma power to 90 W decreased the ILSS value of jute/HDPE composite. Also, tensile and flexure strengths of the composites showed similar trends. (C) 2011 Elsevier B.V. All rights reserved.
Preparation and Characterization of Thin Films by Plasma Polymerization of Glycidoxypropyltrimethoxysilane at Different Plasma Powers and Exposure Times
(Elsevier Science Bv, 2009) Sever, K.; Seki, Y.; Gulec, H. Ali; Sarikanat, M.; Mutlu, M.; Tavman, I.
This study aims to form a functional film on the glass substrates by plasma polymerization of glycidoxypropyltrimethoxysilane (gamma-GPS). Low frequency plasma generator was used to prepare plasma polymer thin films of gamma-GPS (PlzP-gamma-GPS) on glass substrates at different plasma powers (30, 60 and 90W) and exposure times (5, 15 and 30 min). XPS analyses were utilized to reveal the presence of functional groups in plasma polymer films. When higher plasma powers are applied, relative amount of Si-C bonds decreases and the amount of Si-O bonds increases. Contact angle measurements were performed to evaluate surface characteristics. Atomic force microscopy (AFM) studies were carried out to elucidate morphological changes. From AFM observations, it was obtained that the surface roughness slightly increased with the increase of plasma power from 30 to 90 W. (C) 2009 Elsevier B.V. All rights reserved.