Browsing by Author "Gulec T."

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Physical, mechanical and thermal properties of wood/ zeolite/plastic hybrid composites
(2017-01-01) Kaymakci A.; Gulec T.; Hosseinihashemi S.K.; Ayrilmis N.
Effect of zeolite content on the physical, mechanical and thermal properties of wood plastic composites was investigated in this study. To meet this objective, pine wood flour (0, 10, 20, 30, 40, 50 wt%) with compatibilizing agent, zeolite (0, 10, 20, 30, 40, 50 wt%), and polypropylene were compounded in a twin screw co-rotating extruder. The mass ratio of the wood flour to polypropylene was 50/50 (w/w) in all compounds. Test specimens were produced using injection molding machine from the pellets. Physical and mechanical, and thermal (Thermogravimetry Analysis/Differential Scanning Calorimetry) properties of the wood plastic composites were determined. The water absorption and thickness swelling properties of wood plastic composites improved with increasing zeolite content. The flexural and tensile properties of the wood plastic composites decreased with increasing zeolite content. All the wood plastic composites provided the values of flexural strength (58,4-72,9 MPa) and flexural modulus (2718-5024 MPa) that were well over the requirement by the standard specified in ASTM D 6662. The mass loss rates values of wood plastic composites increased with increasing zeolite contents. The Differential Scanning Calorimetry analysis showed that the melt crystallization enthalpies and degree of crystallization of wood plastic composites decreased with increasing zeolite content. The decrease in the Tc and Xc indicated that zeolite was the poor nucleating agent for the wood plastic composites.
Preparation and characterization of high-performance wood polymer nanocomposites using multi-walled carbon nanotubes
(2017-04-01) Kaymakci A.; Ayrilmis N.; Gulec T.; Tufan M.
Effect of industrial grade multi-walled carbon nanotubes on mechanical, decay, and thermal properties of wood polymer nanocomposites was investigated. To meet this objective, pine wood flour, polypropylene with and without coupling agent (maleic anhydride grafted polypropylene), and multi-walled carbon nanotube (0, 1, 3, 5 wt%) were compounded in a twin screw co-rotating extruder. The mass ratio of the wood flour to polypropylene was 50/50 (w/w) in all compounds. Test specimens were produced using injection molding machine from the pellets. The flexural and tensile properties, biological durability, and thermal analysis (thermogravimetric analysis and differential scanning calorimetry) of the nanocomposites were investigated. The flexural and tensile properties of the wood polymer nanocomposites increased with increasing content of the industrial grade multi-walled carbon nanotubes (from 1 to 5 wt%) and maleic anhydride grafted polypropylene (3 wt%). The mass loss rates of the wood polymer nanocomposites decreased with increasing amounts of the maleic anhydride grafted polypropylene and industrial grade multi-walled carbon nanotube. The differential scanning calorimetry analysis showed that the melt crystallization enthalpies of the wood polymer nanocomposites increased with increasing amount of the industrial grade multi-walled carbon nanotubes. The increase in the Tc indicated that the industrial grade multi-walled carbon nanotubes were the efficient nucleating agent for the wood polymer nanocomposites.
Surface properties and hardness of polypropylene composites filled with sunflower stalk flour
(2013-02-01) Kaymakci A.; Ayrilmis N.; Gulec T.
The effects of agricultural flour content on surface roughness, wettability, and surface hardness of injection molded polypropylene (PP) composites was investigated. Four content levels of the waste sunflower stalk flour (WSF) were mixed with the PP with and without maleic anhydride grafted PP (MAPP) as a coupling agent. Contact angle measurements were performed using a goniometer connected with a digital camera. Three roughness parameters, average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax), were used to evaluate surface roughness. The surface roughness increased with increasing WSF content while their wettability decreased. The unfilled (neat) PP composites had the lowest surface roughness, while the roughest surface was found for the PP composites filled with 60 wt% WSF. The surface smoothness of the composites was noticeably increased by addition of the compatibilizer MAPP while the wettability was decreased. The scratch hardness of the PP composites increased significantly with increasing WSF. The incorporation of the coupling agent increased the scratch hardness of the specimens. The Brinell hardness increased with increasing filler loading. At similar filler loading the composites with MAPP had lower Brinell hardness value than those without MAPP.
Utilization of Sunflower Stalk in Manufacture of Thermoplastic Composite
(2013-12-01) Kaymakci A.; Ayrilmis N.; Ozdemir F.; Gulec T.
Dimensional stability and mechanical performance of polypropylene thermoplastic composites filled with sunflower stalk (SS) flour at 30, 40, 50, and 60 wt% contents of the SS flour were investigated. The thickness swelling and water absorption of the specimens increased with increasing SS flour content. The modulus in the flexural and tensile improved with increasing SS flour content while the tensile and flexural strengths of the specimens decreased. The use of maleic anhydride polypropylene (3 wt%) had a positive effect on the dimensional stability and mechanical properties of the polypropylene thermoplastic composites filled with SS flour. The melting temperature of polypropylene decreased with increasing content of the SS flour. The degree of crystallinity of filled polypropylene composites between fibre loading of 0-30 % by weight was higher than that of unfilled polypropylene composites. However, further increment in the filler content decreased the degree of crystallinity. The obtained results showed that SS flour could be potentially suitable raw material in the manufacture of polypropylene composites. © 2012 Springer Science+Business Media New York.