Yazar "Ermeydan, Mahmut A." seçeneğine göre listele
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Öğe A comparative study on photodegradation of twenty-three wood species after UV irradiation(Pergamon-Elsevier Science Ltd, 2024) Tomak, Eylem D.; Ermeydan, Mahmut A.; Can, Ahmet; Aydin, Mehmet A.The study investigates the effect of UV irradiation on different native and exotic wood species which is an open subject of research. Thirteen native wood species and ten exotic wood species, totally twenty-three wood species, all important for wood industry in Turkey, were subjected to UVA-340nm irradiation with a constant irradiance of 0.89 W/m2/nm and a temperature of 60 degrees C for 2, 4, 8, 16, 24, 48, 72, 96, 120, 144, 168, 252 and 336 h to determine the critical degradation time for the wood species. A short exposure time (from 2h to 48h) was especially studied since the previous studies reported that important and rapid changes occurred within the initial exposure periods. The effect of UV irradiation on wood surfaces was investigated by color, surface roughness, and FTIR-ATR measurements. The results proved that UV radiation caused a rapid color change for extractive-rich wood species at the initial period of exposure (16h-48h) which decreases upon prolonged exposure. The overall color change and surface roughness were higher for native wood species in a long exposure period than for exotic ones. Elm, oak, plane, walnut, acacia and linden as native wood species, iroko, tiama, acajou, okoume, garapa, sapelli, dibetou and teak as exotic wood species were found to be more resistant to color changes in prolonged irradiation periods, probably due to content of their components especially extractives and lignin. Similar to greater color change found within the beginning of the irradiation period (16h-48h), the first 8h-24h seemed to cause a greater increase in roughness for exotic species and 16h-24h for native wood species probably due to the changes in surface chemistry. Acacia, elm, cherry, beech, tiama, teak and okoume had the highest RI whilst S. pine, ash, poplar, plane, sapelli, limba and iroko had the lowest RI among the wood species. FTIR-ATR analysis demonstrated that UV light ended up with photodegradation of lignin and photooxidation of hemicelluloses which leads carbonyl-containing chromophores, even after short-time exposures (8h-24h).Öğe Durability of poly(?-caprolactone) modified wood under outdoor soil burial test(Springer, 2025) Ermeydan, Mahmut A.; Tomak, Eylem D.This research explores the chemical modification of spruce wood to maintain its resistance and durability properties under soil conditions through ring-opening polymerization using both fresh and re-used epsilon-caprolactone solutions at concentrations of 70% and 100%. Durability of the modified wood was evaluated over 24 months through soil burial tests, and degradation was assessed via mass loss measurements, Fourier-transform infrared spectroscopy, and scanning electron microscopy (SEM) analyses. In addition, compression strength, modulus of rupture, and modulus of elasticity were determined after the soil burial test. Mass loss of 70% PCL modified samples and controls during the 24 months in soil was higher than that of 100% PCL modified samples due to fungi and termite attacks. SEM analysis revealed the presence of fungal hyphae in both the control and 70% PCL-modified samples, indicating that fungal degradation was more pronounced in these groups. Specifically, the middle lamella in these samples exhibited greater structural breakdown compared to the 100% PCL-modified samples, which showed higher resistance to fungal attack. 100% PCL modified samples were highly resistant to the termite attacks, with a slight visible sign of feeding by the termites in MOR and MOE samples, whilst the controls and some samples of 70% PCL modified samples were destroyed by termites. Parallel to findings on mass losses, strength losses were remarkably lower in 100% PCL modified samples than in controls and 70% PCL modified samples, even after termite attack. The results clearly showed that 100% PCL modification protects wood against soil degrading organisms; however, the re-use of epsilon-caprolactone solution more than three times negatively affected the success of the modification process and reduced the properties of modified wood.Öğe Measuring dimensional stability of thermally modified ayous and iroko wood: comparison of the three test methods(Springer, 2025) Tomak, Eylem D.; Ermeydan, Mahmut A.The dimensional stability and moisture content of wood are important physical properties that influence the end-use of wood. These properties can be greatly improved by thermal modification of wood. In this study, three different test methods are studied on thermally modified iroko (Milicia excelsa) and ayous (Triplochiton scleroxylon) wood to compare the methods of measuring dimensional stability behavior. Test methods include (1) repeated water-soaking until saturation, (2) test cycles of water-soaking and drying, and (3) exposure to relative humidity cycles in the air. Test methods revealed enhanced dimensional stability in thermally modified wood samples relative to the unmodified samples. However, the relative dimensional stability behavior varied between the methods. Water-soaking until maximum swelling (Method-1) showed differences in the swelling rate for each wood material. Thermally modified ayous wood swelled more slowly (similar to 44%) than thermally modified iroko wood. Interestingly, subsequent test methods (Methods 2 and 3) showed decreasing dimensional stability especially for modified iroko wood as the wetting-drying cycles increased and iroko wood was kept in high relative humidity such as 85%. The cracks in the cross-section were more in modified iroko samples than in the controls, whilst modified ayous wood had no visible cracks in the cycles of wetting and drying in Method-2. The anti-swelling efficiency of thermally modified ayous wood was found as similar to 45%, 30%, and 40-60% in Method 1, 2 and 3, respectively. The results of the three different methods clearly showed that thermal modification ensured good dimensional stability for ayous wood, whereas in iroko wood insufficient dimensional stability was obtained, especially in Methods 2 and 3. Thermal modification may not be a good option to ensure dimensional stability for iroko wood. For a complete understanding of dimensional stability in wood modification studies, long-term wetting and drying cycles and/or air humidity cycles are recommended especially for extractive-rich wood species.Öğe Natural weathering of spruce wood chemically modified by re-used ?-caprolactone solution(Wiley, 2023) Cambazoglu, Merve; Tomak, Eylem D.; Ermeydan, Mahmut A.Increasing environmental pressures over the last few years have led to attention for non-biocide treatments in the wood protection field. The epsilon-caprolactone modification of wood by substitution or blocking of hydroxyl groups with hydrophobic poly(epsilon-caprolactone) (PCL) is one of the novel modification methods developed in recent years. In this study, ring-opening polymerisation of epsilon-caprolactone in wood cell walls was evaluated by the third and sixth re-use of recovered monomer and by oven-curing method. Spruce samples were modified by re-used epsilon-caprolactone and exposed to the natural weathering agents for 12 months. After weathering, the colour change, surface roughness measurements, and macroscopic and ultra-microscopic observations revealed that the modified wood had better surface properties than reference wood. Fourier-transform infrared (FTIR) analysis proved that PCL could be found on the weathered surface up to the sixth month, but very little amount was detected on the surfaces with a longer weathering period. The results clearly showed that the efficiency of PCL modification with re-use of the monomer solution was sufficient during the initial weathering periods, but efficiency was reduced after a prolonged exposure period.Öğe Role of extractives on the weathering of tropical and temperate wood species in two above-ground fields: coastal or terrestrial(Taylor & Francis Inc, 2024) Ermeydan, Mahmut A.; Dizman, Riza; Tomak, Eylem D.; Can, AhmetThe effect of heartwood extractives on natural weathering of 5 temperate (juniper, walnut, oak, pseudoacacia, and chestnut) and 9 tropical (wenge, teak, iroko, dahoma, moabi, okan, padauk, ipe, and tatajuba) wood species against abiotic degrading agents at two sites was investigated. Wood species were exposed to three-stage extraction, then extracted and un-extracted samples were exposed outdoors for 12 months in two above-ground test sites, coastal or terrestrial. Samples were evaluated regarding moisture content, color change, surface roughness, and surface chemistry (ATR-FTIR) at 1, 3, 6, and 12 months of exposure. Results indicate that roughness and color change increased as the exposure time increased. Among the temperate species, the least rough surfaces were found in juniper, while iroko, ipe, and wenge were for tropical species. The location did not statistically affect roughness. Temperate species generally showed rougher surfaces than tropical species. The remarkable color change occurred in the first 3 months in temperate wood species and between 3 and 6 months in extractive-rich tropical wood species. The highest color change was seen in samples extracted and exposed on the terrestrial test site, while the lowest was in un-extracted samples exposed on the coast. Padauk had the most color change, while moabi had the least. The surfaces of temperate species showed darkening while the surfaces of tropical species showed lightening during the weathering exposure. FTIR studies confirmed that the change in the surface chemistry of temperate species mostly occurs in the first month, while surface degradation of some tropical species can take up to 3 months.Öğe Synergic effect of basalt/wood fiber reinforced polylactic acid hybrid biocomposites against fungal decay(Pergamon-Elsevier Science Ltd, 2023) Can, Ahmet; Tomak, Eylem D.; Ermeydan, Mahmut A.; Aykanat, OnurIn addition to the traditional fibre-reinforced composites, the investigation of novel composites with significant potential for engineering applications attracts increasing attention. In this study, the decay resistance of basalt and/or wood fibre-reinforced polylactic acid (PLA) biocomposites was evaluated with a soil block test by using white rot fungi, Trametes versicolor (Trv) and Irpex lacteus (Irl), and brown rot fungi, Poria placenta (Pop) and Gloeophyllum trabeum (Glt), and a soft rot fungus, Chaetomium globosum (Chg) after 8 weeks of water submersion. Water absorption rate during the water submission and weight losses after the decay test were determined. Furthermore, decay in biocomposites was characterized by SEM and ATR-FTIR. Results showed that the water absorption increased between 52.4-67.5% for wood fibre composites when compared to basalt fibre-reinforced biocomposites. PLA showed good decay resistance against all fungi attacks. However, as the ratio of basalt and wood fibre in the hybrid biocomposites increased, the fungi resistance decreased. The lowest weight loss, 4.9% was found in the biocomposites containing the highest percentage of basalt fibre. On the other hand, the highest weight loss, 54.2% was observed in the composites containing the highest percentage of wood fibre. The results clearly showed that the hybridization of basalt and wood fibres improves the decay resistance of the biocomposites compared to only wood fibre-reinforced composites. However, as the percentage of wood increased in the composites, the decay resistance decreased. SEM and FTIR analysis confirmed the degradation and revealed the degradation mechanism.Öğe Testing the durability of copper based preservative treated bamboos in ground-contact for six years(Springer, 2022) Tomak, Eylem D.; Topaloglu, Elif; Ermeydan, Mahmut A.; Pesman, EmrahIn this study, durability of bamboo samples in terms of the variability of location along culm height (top, middle and bottom) were evaluated in a ground-contact field test for six years in comparison to Scots pine and beech wood samples. Bamboo and wood samples were treated with Wolmanit-CB (CCB) and Tanalith-E (Tan-E) solutions, and then were installed in a field located in the North-West of Turkey. The decay resistance of samples was assessed by weight loss, and compared by SEM observations and FTIR analysis. Furthermore, chemical leaching from the samples was detected by ICP-OES after the test. Results showed that un-treated bamboo and wood samples had a very low durability such that weight losses were found as 64-80% for bamboo and 57-63% for wood samples. The SEM micrographs showed the characteristics decay patterns of soft-rot type I and brown-rot fungi in the parenchyma cells, vessels and fibers in vascular bundles. Fungal hyphae within the cell walls resulted in the gradual breakdown of the cell wall layers. FTIR analysis revealed the mechanism of the biodegradation, which indicates the reduction of carbohydrate content. The weight loss in CCB and Tan-E treated bamboo samples was reduced as 20-45% depending on bamboo height parts, but the wood preservatives did not ensure sufficient resistance for six years against soil degrading organisms since more than half of the chemical amount leached out from the bamboos to soil. Weight losses were well confirmed by chemical leaching rates for both CCB and Tan-E. It was observed that the lower parts of the culm were more durable, which was also in accordance with ICP-OES and SEM analysis. Copper-based preservatives seemed to be more efficient in pine and beech wood samples than bamboos since the impregnability of bamboo was much lower than that of wood.Öğe The impact of aging on the properties of heat-treated iroko wood used as a terrace deck for 10 years(Taylor & Francis Inc, 2025) Ermeydan, Mahmut A.; Tomak, Eylem D.The exposure period and environmental factors can significantly influence the surface degradation of wood. Extended exposure periods are needed for accurately assessing a material's long-term performance, making it essential to study how prolonged exposure affects wood properties. This research focused on examining the impact of heat treatment on the physical properties (dimensional stability, water uptake, and contact angle), mechanical properties (flexural and compression), and surface analysis (FTIR, SEM, roughness, and color) of iroko wood used as a terrace deck over a 10-year period in Bursa, T & uuml;rkiye. Findings revealed that the surface roughness and water uptake of aged iroko increased considerably after exposure. Although heat treatment improved surface quality (roughness, wettability) and color stability initially, heat-treated (HT) iroko partially lost those improvements after the 10-year exposure period. The compression strength and modulus of elasticity of aged HT iroko slightly decreased compared to unaged HT samples, where the rupture modulus decreased remarkably. FTIR analysis and SEM images indicated notable changes in surface composition in heat-treated wood after exposure.Öğe Weathering of wood under indoor and outdoor environmental conditions(Wiley, 2025) Aydin, Mehmet A.; Can, Ahmet; Tomak, Eylem D.; Ermeydan, Mahmut A.This paper investigates the surface properties of 27 wood species exposed to indoor and outdoor weathering agents using above-ground test equipment for 1 year in Bursa, Turkey. For this purpose, colour changes, surface roughness and chemical composition of wood surfaces were analysed at an interval of 3 months during the exposure period. The results showed that the colour change on the wood surfaces exposed to outdoor weathering was observed during the first 3 months, and that the temperate wood species showed much more surface darkening and colour change compared with tropical wood species. In outdoor weathering, the least colour change was found in wenge as a tropical wood, and in walnut and elm as the temperate species, while the greatest colour change was in ayous and poplar. In the case of indoor weathering, iroko and cherry displayed the least amount of colour change, while the most was seen in wenge and Scots pine. Additionally, surface roughness and cracks increased with weather conditions, especially in outdoor conditions. Fourier Transform-infrared spectra revealed chemical changes, especially in carbonyl and lignin groups. Significant darkening, mould growth and crack formation on the surfaces were observed after the ninth month of outdoor weathering. However, cracks or mould formations were not observed on the samples exposed to indoor weathering; only a slight colour change was common. The study showed that the indoor and outdoor degradation agents, wood species and humidity conditions had an important role in the tested parameters.
