Browsing by Author "Kaymakci A."

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Characteristics of hot-compressed poplar wood boards
(2017-11-01) Ucuncu T.; Durmaz E.; Kaymakci A.
The influence of thermal modification by hot-compressing was investigated relative to the physical, mechanical, anatomical, crystallinity, and colour characteristics of poplar wood boards. The boards were modified by a hotcompressed method under various temperature stages. The physical and mechanical properties of hot-compressed poplar wood increased with increased pressing temperature. Likewise, the highest crystallinity index (68.7%) of X-ray diffraction (XRD) analyses was found in the samples pressed at 210 °C. Microscopic investigation, revealed that there were some structural deformations in early and late wood, annual ring, etc., of the compressed samples at 170 °C, 190 °C, and 210 °C. In a colour measurement test, it was determined that samples had different colour values in terms of temperature increase. The results achieved in this study demonstrated that the physical and mechanical properties of hotcompressed boards improved with increased press temperature. As a result, a thermal compression method could be preferred to advance endusage features of low-density wood materials produced from fast-growing tree species like poplar, Douglas fir, spruce, yellow pine, eucalyptus, etc.
Effect of Freeze–Thaw Cycling on the Screw Direct Withdrawal Resistance of Beech, Ozigo, and Okoume Plywoods
(2023-06-01) Birinci E.; Kaymakci A.
Wood has been used in the construction, furniture, and automotive industries since ancient times. In areas where wood material is used, it is combined with various fasteners. The durability of the products produced using wooden materials depends on the performance of the fasteners. Since wood is a hygroscopic and biodegradable material, various changes occur in its structure when exposed to external weather conditions. Wood materials used especially in the field of construction and urban furniture are exposed to effects such as extreme temperatures, freezing, moisture, or drying depending on the seasons. In this study, the effect of the freeze–thaw cycling (FTC) process on screw direct withdrawal resistance (SDWR) of plywood produced from beech, ozigo, and okoume species was investigated. In this context, the effects of screwing time (before or after), screw orientation (face or edge), the number of cycles (0 to 7) in the FTC process, and plywood type parameters on SDWR were investigated. As a result of the tests, when the mean SDWR values were examined according to the plywood type, the highest values were obtained in beech, ozigo, and okoume plywood, respectively. Considering the screwing time parameter, it was determined that there was no statistically significant difference between the mean SDWR values in other plywood types except beech plywood (p < 0.05). When the screw orientation parameter was examined, screwing in the face direction gave better results than screwing in the edge direction in all plywood types. There was a decrease in the mean SDWR values that was inversely proportional to the increase in the number of cycles in FTC-treated plywood.
Effect of Heat Treatment Parameters on the Physical, Mechanical, and Crystallinity Index Properties of Scots Pine and Beech Wood
(2022-01-01) Birinci E.; Karamanoglu M.; Kesik H.İ.; Kaymakci A.
Effects of heat treatment parameters on the physical properties, mechanical properties, and crystallinity index of Scots pine and beech wood were investigated. Scots pine (Pinus sylvestris L.) and beech (Fagus orientalis Lipsky) sapwood samples were prepared in 2 cm × 2 cm × 36 cm dimensions by considering the physical and mechanical tests. The samples were heat-treated for 2 h and 4 h at 150 °C, 180 °C, and 210 °C in an atmospheric environment. The shrinking and swelling percentages of all samples were calculated. The compressive strength, bending strength, modulus of elasticity (MOE), and hardness tests were carried out. X-ray diffraction (XRD) was performed to calculate the crystallinity index values. As a result of the study, it was determined that heat treatment generally had a positive effect on the physical properties of Scots pine and beech samples. It was observed that the bending strength of the wood samples decreased up to 180 °C as the temperature increased and then increased. It was determined that the MOE of the Scots pine and beech wood decreased with the heat treatment. As the heat treatment temperature and time were increased, the crystallinity index values initially increased partially and then decreased.
Effect of Processing Technology, Nanomaterial and Coupling Agent Ratio on Some Physical, Mechanical, and Thermal Properties of Wood Polymer Nanocomposites
(2023-05-01) Birinci E.; Kaymakci A.
The goal of this study is to find out how some properties of wood–polymer nanocomposites are affected by the processing technology, the nanomaterials, and the ratio of coupling agents. To achieve this objective, the extruded and dry blended samples are made from wood flour with MAPP, ZnO nanoparticles (0, 1, 3, and 5 wt%), and polypropylene. The mechanical properties of the nanocomposites improve significantly with ZnO and MAPP loading. Due to the more homogeneous structure of nanocomposites, better mechanical results are obtained with the extrusion method. With ZnO and MAPP loading, the thermal stability of nanocomposites improves. The storage and loss modulus values indicate that the processing technology of nanocomposites could be a key factor in the resistance of the materials obtained by extrusion. The storage and loss modulus of nanocomposites manufactured by the extrusion technology are determined to be higher than those of the samples produced using the dry blending method.
Effect of sepiolite clay nanofibers on physical, mechanical, and thermal properties of wood-plastic nanocomposites
(2022-10-01) Kaymakci A.
This study was to investigate sepiolite clay nanofibers (SCNs) on some physical, mechanical, and thermal properties of wood-plastic nanocomposites. To meet this objective, pinewood flour with maleic anhydride polypropylene (PP), sepiolite nanofibers (0, 1, 3, 5, and 7 wt%), and PP were compounded in a twin-screw corotating extruder. The mass ratio of the wood flour to PP was 50/50 (wt%/wt%) in all compounds. The test specimens were produced using an injection molding machine from the pellets. Flexural and tensile properties, thickness swelling, water absorption, thermogravimetric analysis, and morphology of the manufactured nanocomposites were evaluated. Based on the findings in this study, flexural and tensile properties of the wood-plastic nanocomposites increased with increasing the content of the sepiolite nanofibers. By increasing the amount of SCNs, thickness swelling and water absorption properties of wood-plastic nanocomposites were improved. Increasing the loading of SCNs increased the amount of residual ash and thermal stability.
Effect of sepiolite clay nanofibers on physical, mechanical, and thermal properties of wood-plastic nanocomposites
(2022-10-01) Kaymakci A.; Kaymakci, A
This study was to investigate sepiolite clay nanofibers (SCNs) on some physical, mechanical, and thermal properties of wood-plastic nanocomposites. To meet this objective, pinewood flour with maleic anhydride polypropylene (PP), sepiolite nanofibers (0, 1, 3, 5, and 7 wt%), and PP were compounded in a twin-screw corotating extruder. The mass ratio of the wood flour to PP was 50/50 (wt%/wt%) in all compounds. The test specimens were produced using an injection molding machine from the pellets. Flexural and tensile properties, thickness swelling, water absorption, thermogravimetric analysis, and morphology of the manufactured nanocomposites were evaluated. Based on the findings in this study, flexural and tensile properties of the wood-plastic nanocomposites increased with increasing the content of the sepiolite nanofibers. By increasing the amount of SCNs, thickness swelling and water absorption properties of wood-plastic nanocomposites were improved. Increasing the loading of SCNs increased the amount of residual ash and thermal stability.
Effect of titanium dioxide on some mechanical, thermal, and surface properties of wood-plastic nanocomposites
(2019-02-01) Kaymakci A.
The effects of TiO 2 (titanium dioxide) loading were evaluated relative to mechanical, thermal, and surface properties of the wood-plastic nanocomposites (WPNs). Pine wood flour, mixed with maleic anhydride polypropylene (MAPP), TiO 2 nanoparticles (0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, and 5 wt%), and polypropylene, was compounded in a twin screw co-rotating extruder. The mass ratio of the wood flour to polypropylene (PP) was 50/50 (w/w) in all compounds. Test specimens were produced using injection molding machine from the pellets. Flexural and tensile properties, thermogravimetric analysis, surface roughness, wettability, and morphology of the manufactured nanocomposites were evaluated. Flexural and tensile properties of the wood-plastic nanocomposites increased with the increasing content of the TiO 2 . The surface roughness of the wood-plastic nanocomposites was reduced by increasing the content of TiO 2 . Increasing the loading of TiO 2 increased the amount of residual ash and thermal stability.
Effect of titanium dioxide on some mechanical, thermal, and surface properties of wood-plastic nanocomposites
(2019-02-01) Kaymakci A.; Kaymakci, A
The effects of TiO 2 (titanium dioxide) loading were evaluated relative to mechanical, thermal, and surface properties of the wood-plastic nanocomposites (WPNs). Pine wood flour, mixed with maleic anhydride polypropylene (MAPP), TiO 2 nanoparticles (0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, and 5 wt%), and polypropylene, was compounded in a twin screw co-rotating extruder. The mass ratio of the wood flour to polypropylene (PP) was 50/50 (w/w) in all compounds. Test specimens were produced using injection molding machine from the pellets. Flexural and tensile properties, thermogravimetric analysis, surface roughness, wettability, and morphology of the manufactured nanocomposites were evaluated. Flexural and tensile properties of the wood-plastic nanocomposites increased with the increasing content of the TiO 2 . The surface roughness of the wood-plastic nanocomposites was reduced by increasing the content of TiO 2 . Increasing the loading of TiO 2 increased the amount of residual ash and thermal stability.
Effects of heat treatment on some characteristics of Scots pine (Pinus sylvestris L.) wood
(2019-01-01) Durmaz E.; Ucuncu T.; Karamanoglu M.; Kaymakci A.
Heat treatment of wood materials is generally performed to improve the physical, mechanical, chemical, surface, thermal, and crystallinity characteristics. In this way, the usage areas of wood material in different purposes can be expanded by means of heat treatment. The goal of this study was to determine the physical, mechanical, chemical, crystallinity, and surface properties of heat-treated Scots pine (Pinus sylvestris L.) wood. The test samples were heat-treated at 120 °C, 150 °C, 180 °C, and 210 °C for 4 and 6 h in a laboratory-scale oven. The shrinking and swelling chracteristics of wood was decreased as a function of heat treatment processes. Bending strength, compression strength, and modulus of elasticity decreased. In addition, lignin ratios and crystallinity index increased as temperature and duration of the treatment were increased. Consequently, heat-treated wood materials can be used in various areas by developing some of their properties.
Evaluation of Heat Treatment Parameters’ Effect on Some Physical and Mechanical Properties of Poplar Wood with Multi-criteria Decision Making Techniques
(2021-01-01) Kaymakci A.; Bayram B.Ç.
Effects of the heat treatment parameters were evaluated relative to some physical and mechanical properties of poplar wood (Populus alba L.) with use of two of the prominent multi criteria decision-making (MCDM) techniques: Entropy and The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). To meet this objective, the test samples were heat-treated at 120, 150, 180, and 210 °C for 2 and 4 h in a laboratory-scale oven. With increasing temperature and duration, the shrinkage and swelling ratios of heat-treated samples were improved. However, the bending strength, modulus of elasticity, and compression strength generally decreased with increasing process temperature and duration. According to (MCDM) analyses, thermal modification definitely improved the physical properties of wood up to a point. Bending strength was found to be the most important determinant of heat treatment success. The other determinants were identified as swelling, compression strength, shrinkage, and modulus of elasticity, respectively. Also, the best results were obtained at 120 °C for 2 h. In general, heat treatment above 150 °C or 4 h is not recommended.
Impact of PF and MUF adhesives modified with TiO2 and SiO2 on the adhesion strength
(2018-01-01) Ozcifci A.; Kara M.E.; Kaymakci A.
The purpose of this study was to evaluate adhesion strength of phenol formaldehyde (PF) and melamine urea formaldehyde (MUF) adhesives modified with nano-technological products on the adhesion strength of different wood species. For this purpose, the effect of nano-TiO2 and nano-SiO2 on bonding performance and structural properties of PF and MUF were researced. And also, TiO2 and SiO2 chemicals were chosen as a rate of 2%, 4%, 6%, 8% within the adhesives. The bonding strength tests of the acquired Uludag fir and aspen boards were measured with a Universal Zwick Roell brand testing device in accordance with TS EN 205 standards. The obtained results showed that the highest bonding strength for Uludag fir wood was 8.27 N.mm-2with PF adhesive mixed as 8% of SiO2 and the lowest was 5.91 N.mm-2 with MUF adhesive mixed as 2% TiO2, respectively. For aspen wood, the highest value was determined as 7.32 N.mm-2with PF adhesive into which 8% of TiO2 had been added and the lowest was as 5.55 N.mm-2with MUF adhesive into which % 6 TiO2 had been added. In conclusion it was determined that compared to the control samples the bonding strength of wood materials manufactured with the addition of nanoproduct into the PF adhesive enhanced the bonding strength by approximately 30% and 40% within MUF adhesive.
Influence of Repeated Injection Molding Processing on Some Mechanical and Thermal Properties of Wood Plastic Composites
(2016-01-01) Kaymakci A.; Ayrilmis N.
The influence of repeated cycles of injection molding on some mechanical and thermal properties of wood plastic composites (WPCs) was investigated. Pine wood flour (50 wt%) was mixed with HDPE (50 wt%) containing compatibilizing agent (MAPE, 3 wt%) in a co-rotating twinscrew extruder. The test specimens were produced by injection molding from the pellets dried to the moisture content (MC) of 1%. After the mechanical properties of the WPC test specimens were determined, the failed specimens were subsequently pelletized. These pellets were stored and dried for 4 to 6 h until the repeated injection was molded. These processes were repeated seven times. The results revealed that the flexural strength of WPCs increased by about 5.26% from the original granules to the third injection cycle, but further increments in the number of cycles decreased the flexural strength. The tensile strength and tensile modulus of the WPC specimens increased until the third cycle of injection molding while they tended to decrease after the third injection cycle.
Investigation of correlation between Brinell hardness and tensile strength of wood plastic composites
(2014-03-01) Kaymakci A.; Ayrilmis N.
The relationship between Brinell hardness and tensile strength of wood plastic composites (WPC) as a function of wood filler content was investigated. The sawdust flour was compounded with polypropylene at 30%, 40% or 50% (by weight) content with and without coupling agent, maleic grafted polypropylene with anhydride, in a twin screw co-rotating extruder. Test specimens were produced by injection moulding process from the pellets dried to moisture content of 1%. The relationship between Brinell hardness and tensile strength for all the filler loading levels was studied using linear regression method. The strong correlation was found between the Brinell hardness and tensile hardness of the WPCs as the filler content was between 30 and 40 wt%. The strong correlation showed that the Brinell hardness could be a good indicator for tensile strength of the WPCs. © 2013 Elsevier Ltd.
Optimizing lumber drying schedules for oriental beech and sessile oak using acoustic emission
(2020-08-01) Ünsal Ö.; Dündar T.; Görgün H.V.; Kaymakci A.; Korkut S.; As N.
The aim of this work was to detect sounds providing evidence of the creation of drying defects and to correlate such data with drying quality. A further goal was to establish sound wave thresholds of ideal drying through the drying process by using an acoustic emission (AE) monitoring method. Thus, it is projected to decrease long drying times and also drying costs by reaching to ideal drying schedules. In this study, commercially preferred sessile oak and oriental beech structural lumbers were dried with three different schedules in a conventional kiln. The lumbers were "listened to" with AE sensors while drying according to the first two schedules, which were called protective and severe, respectively. AE events of the drying experiments were compared with ambient conditions and drying classes according to the standard of European Drying Group. The third drying schedule was optimized based on the AE peaks and applied. The results showed that ideal drying times were reduced up to 19% relative to the protective drying schedule, while obtaining the same drying quality for both species.
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.
Potential use of cotton dust as filler in the production of thermoplastic composites
(2017-12-01) Ayrilmis N.; Güleç T.; Peşman E.; Kaymakci A.
The effect of cotton dust as filler on the mechanical and thermal properties of polypropylene composites was investigated and the results were compared with the properties of wood plastic composites. Cotton dust was obtained from the dust filtration system located in a textile manufacturing unit. Different mixtures of cotton dust (30 to 60 wt%) or wood flour (30 to 60 wt%) were compounded with polypropylene with a coupling agent (maleic anhydride grafted polypropylene 3 wt%) in a twin-screw co-rotating extruder. The test specimens were produced by injection molding machine. The tensile strength and flexural modulus of the specimens improved with the increase in the filler content. There was no significant difference in the strength and modulus values between the cotton dust and wood flour filled composites. The highest thermal stability was found to be in the composites produced with 40 wt% of cotton dust according to the results of differential scanning calorimetry analysis. Based on the findings obtained from the present study, the optimum mechanical and thermal properties for the filled polypropylene composites were found to be a 50/50/3 formulation of cotton dust, polypropylene, and maleic anhydride grafted polypropylene, respectively.
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 characteristics of wood polypropylene nanocomposites reinforced with multi-walled carbon nanotubes
(2019-01-15) Kaymakci A.; Birinci E.; Ayrilmis N.
Effect of multi-walled carbon nanotubes (MWCNT) content on the surface roughness, wettability, and scratch hardness properties of wood/polypropylene nanocomposites were 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 or 5 wt%) were compounded in a twin screw co-rotating extruder. The mass ratio of the pine wood flour to polypropylene was 50/50 (w/w) in all the composite formulations. Test samples were manufactured using injection molding machine from the pellets. The surface roughness, wettability, and scratch hardness properties of the wood/polypropylene nanocomposites reinforced with multi-walled carbon nanotubes were determined. The surface roughness values of the nanocomposite specimens decreased with increasing MWCNT content. The MWCNT reinforced wood/polypropylene nanocomposites without coupling agent had higher surface roughness values than the ones with coupling agent. The wettability of the nanocomposite specimens decreased with increasing content of the MWCNT. The incorporation of the coupling agent into the wood/polypropylene nanocomposites decreased the wettability of the specimens. The scratch hardness values of the nanocomposite specimens improved with increasing MWCNT content.
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.
Surface roughness and wettability of polypropylene composites filled with fast-growing biomass: Paulownia elongata wood
(2014-01-01) Kaymakci A.; Ayrilmis N.
This study investigated the surface roughness and wettability of polypropylene composites filled with Paulownia elongata wood flour with and without maleic anhydride-grafted polypropylene at different wood flour contents (30, 40, 50, and 60 wt%). The surface roughness values of the filled polypropylene composites decreased with increasing content of the polypropylene. The polypropylene composites without the maleic anhydride-grafted polypropylene were found to have higher surface roughness but better wettability as compared with the ones with the maleic anhydride-grafted polypropylene. The wettability of polypropylene composites increased with increasing content of the wood flour. The incorporation of the coupling agent in the polypropylene composites decreased the wettability of the specimens compared with untreated ones. The test result showed that P. elongata wood flour could be utilized in the production of the filled polypropylene composites because of their satisfying surface properties of the composites. © The Author(s) 2013.