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Article Citation - WoS: 6Citation - Scopus: 6Modification of Poly(methyl Methacrylate) Surfaces With Oxygen, Nitrogen and Argon Plasma(Amer Scientific Publishers, 2014) Ozgen, Ozge; Özgen, Özge; Hasirci, Nesrin; Özgen, Özge; Physics Group; Physics GroupPoly(methyl methacrylate) (PMMA) is a strong and lightweight material used in wide range of areas changing from lenses to medical and dental devices. In this study, PMMA samples were modified by oxygen, nitrogen and argon plasma with application of 100 watts 13.56 MHz radio frequency (RF) discharge for different periods (5 min, 15 min and 30 min) and the effects of plasma parameters on surface chemistry, hydrophilicity, surface free energy and topography were examined. XPS analysis showed formation of free carbonyl and carbonate groups by oxygen plasma, carboxylic acid and free carbonyl by argon plasma, and imine, primary amine, amide and nitrozo functional groups by nitrogen plasma treatments. For all cases plasma treatment created more hydrophilic surfaces with lower water contact angles than that of pristine PMMA. Also, plasma caused an increase in the surface free energy and its' polar components determined by Geometric Mean, Harmonic Mean, and Acid-Base approaches. AFM results showed increasing roughness parallel to the duration of plasma. As a result, each plasma treatment caused different functionalities and physical topographies on PMMA surfaces and different functionalities can be used for further developments such as binding specific active molecules to design biosensors or medical devices.Article Citation - Scopus: 2An Environmentally Friendly Method of Cutting and Forming of Materials by Boron Nitride Coated Tools(Inderscience Publishers, 2014) Kaftanoǧlu,B.; Dökmetaş,N.To decrease the undesirable effects on global warming and environmental pollution, manufacturing techniques should aim to use less energy, generate less pollution to the environment and aim at higher performance in shaping and cutting materials. In this paper, a new coating technique is presented for cutting and forming tools so that they can withstand higher temperatures, preserve their surface quality and cutting edge longer and require minimum quantity of lubrication (MQL) and achieve a longer life. It is known that coolants used in manufacturing cause environmental problems and their processing raises the manufacturing cost. Therefore, MQL or dry cutting is preferred if the tool material can withstand the high temperatures. A new technology of boron nitride (BN) coating using a physical vapour deposition (PVD) system is developed. BN coatings are applied on cutting tools and forming dies. Experiments and industrial applications show an increase in tool life. MQL and manufacturing at higher temperatures can be used due to the stability of BN. Copyright © 2014 Inderscience Enterprises Ltd.
