Browsing by Author "Gulec, H. Ali"

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Effect of the Low and Radio Frequency Oxygen Plasma Treatment of Jute Fiber on Mechanical Properties of Jute Fiber/Polyester Composite
(Korean Fiber Soc, 2010) Seki, Yoldas; Sarikanat, Mehmet; Sever, Kutlay; Erden, Seckin; Gulec, H. Ali
We investigated the surface modification of jute fiber by oxygen plasma treatments. Jute fibers were treated in different plasma reactors (radio frequency "RF" and low frequency "LF" plasma reactors) using O-2 for different plasma powers to increase the interface adhesion between jute fiber and polyester matrix. The influence of various plasma reactors on mechanical properties of jute fiber-reinforced polyester composites was reported. Tensile, flexure, short beam shear tests were used to determine the mechanical properties of the composites. The interlaminar shear strength increased from 11.5 MPa for the untreated jute fiber/polyester composite to 19.8 and 26.3 MPa for LF and RF oxygen plasma treated jute fiber/polyester composites, respectively. O-2 plasma treatment also improved the tensile and flexural strengths of jute fiber/polyester composites for both plasma systems. It is clear that O-2 plasma treatment of jute fibers by using RF plasma system instead of using LF plasma system brings about greater improvement on the mechanical properties of jute/polyester composites.
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.