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Accelerated weathering resistance of high-density polyethylene composites reinforced with microcrystalline cellulose and fire retardants
(Elsevier Ltd, 2021) Dönmez Çavdar, A.; Dizman Tomak, Eylem; Boran, Torun, S.; Arpaci, S.S.
In this study, high-density polyethylene (HDPE) composites reinforced with microcrystalline cellulose (MCC) and fire retardants, ammonium zeolite (AZ) and mono ammonium phosphate (MAP) were exposed to ultraviolet (UV) radiation using an accelerated weathering test chamber for total of 672 h. The weathering effects on the surface characterization and morphology of the composites were examined with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), color, gloss and surface roughness measurements. Furthermore, tensile and flexural tests were determined after the weathering exposure. The results showed that the weathering of composites led to changes on the investigated properties. As a result of surface roughness measurement, the highest Rz (mean peak-to-valley height) values were obtained from the composite surfaces of the HDPE/AZ10 (86/10, w/w) and the HDPE/MCC/MAP10 (71/15/10, w/w). The SEM studies confirmed that AZ addition resulted in some protrusion at the composite surfaces while MAP addition caused some coarsening on the composite surfaces. After the weathering, the decrease in mechanical strengths of the samples was found as 32%. The overall mechanical properties were not considerably affected with 672 h of the weathering exposure. © 2021 Elsevier Ltd
Bakır, çinko ve seryum içeren kimyasal maddeler ile odunun antifungal özelliklerinin iyileştirilmesi
(2021) Dizman Tomak, Eylem; Günaydın, Ayşegül; Arpacı, Şebnem Sevil
Organik bir malzeme olan odun, odun tahripçisi organizmalar tarafından bozundurulmakta ve tahrip edilebilmektedir. Bu amaçla geçmişten günümüze kadar birçok emprenye maddesi geliştirilmiş ve halen de geliştirilmeye devam etmektedir. Bu çalışmada, sarıçam örnekleri %0,25, 0,5, 1, 1,5 ve 2,5 konsantrasyon seviyesinde çinko klorür (ZnCl2), nano seryum oksit (CeO2), nano çinko oksit (ZnO) ve bakır II sülfat (CuSO4) ile emprenye edilerek, örneklerin esmer (Coniophora puteana) ve beyaz (Trametes versicolor) çürüklük mantar saldırılarına karşı dayanımı belirlenmiştir. Emprenye maddelerinin etkinliği, yıkanmış ve yıkanmamış örneklerde tespit edilmiştir. Ayrıca, yıkanma sularında zehirlilik tespiti, çalışmada kullanılan mantar türlerinin misel gelişimi ile takip edilmiştir. Sonuçlar, ZnCl2’ün her iki mantarın saldırısını önlemede etkili olduğunu göstermiştir. Ayrıca ZnCl2’ün yıkanmaya karşı dayanıklı olduğu ve test edilen kimyasal maddeler arasında en etkili sonucun ZnCl2 ile alındığı tespit edilmiştir. Biyolojik dayanım için CeO2 ve CuSO4’ün minimum %1,5’luk konsantrasyonlarının gerekli olduğu belirlenmiştir. Yıkanmamış örneklerde ZnO’in %1 konsantrasyon seviyesi her iki mantara karşı dayanım gösterirken, yıkanmış örneklerin tüm grupları T. versicolor’a karşı bir dayanım göstermemiştir. Yıkanma sularının zehirlilik testinde, 2 hafta sonunda misel gelişimi, kontrol örneklerinde görülen büyüme seviyesine benzer bulunmuştur.
Biological properties of nutshell and microcrystalline cellulose (MCC) filled high density polyethylene composites
(International OCSCO World Press, 2016) Boran, S.; Dizman Tomak, Eylem; Dönmez Çavdar, A.
Purpose: The composites based on natural fibre and wood can be destroyed by fungi attack, even the lignocellulosic materials were used as filler in hydrophobic thermoplastic matrix. The aim of this study was to investigate the effect of microcrystalline cellulose (MCC) and nutshell fibre content on decay resistance of natural fibre composites. Design/methodology/approach: Half of the composite samples were immersed in water for 60 days and then incubated by fungi to investigate the leaching effect on biological resistance. Furthermore, water absorption rate and thickness swelling of samples were determined during water immersing. For this purpose, total nine thermoplastic composites filled different MCC rate (5%, 10% and 15%) and nutshell content (30%) were produced. Decay test were conducted by using a white rot fungus–Trametes versicolor, and a brown rot fungus–Tyromyces palustris, according to EN 113 standard. Findings: Based on findings from this study, weight loss, water absorption rate and thickness swelling correlated with lignocellulosic content in composites. Samples exhibited less than 1% weight loss in decay test and excellent biological resistance against testing fungi. Research limitations/implications: Weight loss (%) and moisture content (%) values of MCC-nutshell HDPE composites after Tyromyces palustris and Trametes versicolor attack were found under 3% and 20%, respectively. Low weight loss values obtained in the study are supposed to be related with the low moisture content. Originality/value: There is not a study dealing with the decay resistance of WPCs produced by a combination of nutshell and MCC fibres. In addition, there is not a substantial study on the effects of MCC/plastic ratio for decay performance of WPCs contained nutshell after long-term leaching test. © International OCSCO World Press. All rights reserved. 2016.
Changes in chemical composition of decayed Scots pine and beech wood
(Walter De Gruyter Gmbh, 2014) Dizman Tomak, Eylem
In this study, changes in chemical composition of aged and unaged Scots pine and beech wood decayed by brown-rot fungi Coniophora puteana and Poria placenta were presented by Fourier transform infrared (FT-IR) spectra. Samples were exposed to six complete cycles of accelerated aging for 12 days and then subjected to brown-rot fungi attack for 8 weeks. Weight loss of samples was found to be 25-46% depending on wood and fungi species and being aged ones. Accelerated aging treatments seemed to have a slight role on chemical composition of Scots pine and beech samples while they increased biodegradation of samples. FT-IR spectra showed degradation of wood carbohydrates revealed by reduction of the peaks responsible for hemicellulose and cellulose at 1730, 1370, 1150, and 897 cm(-1) in pine and 1730, 1370, 1027, and 897 cm(-1) in beech. Stronger lignin peaks at 1650, 1593, 1506, 1455, 1422, 1261, and 1230 cm(-1) in pine and 1650, 1506, 1455, and 1422 cm(-1) in beech were obtained after decay test. FT-IR spectra of samples were consistent with the degradation mechanism of brown-rot fungi. In general, changes in the carbohydrate and lignin peaks were greater in samples exposed to accelerated aging treatments for both wood species.
Changes in surface and mechanical properties of heat treated wood during natural weathering
(Elsevier Sci Ltd, 2014) Dizman Tomak, Eylem; Ustaomer, Derya; Yildiz, Sibel; Pesman, Emrah
In this study, it was aimed to investigate the changes in moisture content, color, surface roughness, compression strength parallel to grain, modulus of rupture and modulus of elasticity of heat treated ash, iroko, Scots pine and spruce wood species during natural weathering for two years. Samples were removed at 6-month intervals for performance evaluation, and test results were compared with the controls. Moisture content of heat treated samples was found to be lower than that of control samples for all exposure periods. Heat treatment significantly changed original wood color as well as weathering factors. Wood surfaces become rougher within longer weathering exposure period. Natural weathering factors caused a decrease for all strength properties. Reduction rate for strength properties of heat treated samples was relatively lower than that of control samples. Heat treatment also seemed to improve color stability and surface quality of samples after weathering. (C) 2014 Elsevier Ltd. All rights reserved.
Characterization of weathered MCC / nutshell reinforced composites
(Elsevier Ltd, 2021) Boran Torun S.; Dizman Tomak, Eylem; Donmez Cavdar A.; Mengeloglu F.
Microcrystalline cellulose (MCC) and nutshell fiber reinforced high-density polyethylene (HDPE) composites were exposed to accelerated weathering for total of 672 h. The effects of weathering exposure on the mechanical, surface and morphological properties of the composites were investigated. The results revealed that the weathering exposure caused a slight decrease on tensile and flexural strengths whilst the modulus of elasticity increased up to 62%. The MCC / nutshell reinforced composites had higher color changes and gloss loss than MCC reinforced composites. Addition of MCC and nutshell to HDPE composites increased surface roughness of samples. After the weathering, the polymer band intensities decreased due to the degradation. The SEM observations on the exposed composites are in accordance with the surface roughness of composites after weathering. The investigated properties of MCC/nutshell filled HDPE composites were less affected by weathering exposure than those of composites without nutshell.
Effect of artificial weathering on the properties of heat treated wood
(Elsevier Sci Ltd, 2013) Yjidiz, Sibel; Dizman Tomak, Eylem; Yildiz, Umit C.; Ustaomer, Derya
This study aims to investigate the change in chemical composition, surface characteristic and mechanical properties of heat treated four wood species (ash, iroko, Scots pine and spruce) during artificial weathering from 400 h to 1600 h in relation to their color changes, surface roughness, compression strength, modulus of elasticity, modulus of rupture and surface composition. Original color of wood species was significantly changed by heat treatment and artificial weathering. Artificial weathering decreased color change of heat treated wood samples except for iroko. Color change significantly increased with longer weathering exposure for heat treated wood samples however similar trend was not observed for control samples exposed to weathering factors. In general, heat treatment alone did not have a considerable effect on surface roughness of wood. Heat treatment seemed to protect wood surface to become rougher after weathering for softwoods. Compression strength and MOR of samples decreased while MOE increased during heat treatment. Compression strength, MOR and MOE of samples decreased considerably with longer weathering exposure both for heat treated and control samples. Softwood species seemed to be more affected by heat and weathering than hardwood species did with respect of loss on the strength properties. Severe delignification and hemicellulose degradation occurred in heat treated and control samples for all wood species during weathering from 400 h to 1600 h evident from rapid decrease at 1504/1508 cm(-1) and 1730 cm(-1), respectively. Heat treatment did not fully protect hemicellulose degradation and delignification occurred by weathering with longer exposure periods. (C) 2013 Elsevier Ltd. All rights reserved.
Effect of Chemical Modification with Maleic, Propionic, and Succinic Anhydrides on Some Properties of Wood Flour Filled HDPE Composites
(North Carolina State Univ Dept Wood & Paper Sci, 2014) Cavdar, Ayfer D.; Mengeloglu, Fatih; Karakus, Kadir; Dizman Tomak, Eylem
One of the biggest disadvantages of wood, as a potential reinforcement for thermoplastics, is its hydrophilicity. The aim of this study was to evaluate the effect of chemical modification of wood flour on mechanical, thermal, and fire properties of filled high-density polyethylene composites. For this purpose, aspen flour was modified with maleic, propionic, and succinic anhydrides. The modified wood flour and high-density polyethylene were compounded into pellets by single-screw extrusion, and test samples were prepared by injection molding. Tensile and flexural tests, impact testing, limiting oxygen index, TGA, and SEM analyses were conducted both for modified and un-modified samples. Based on the test results, chemical modification enhanced the properties of thermoplastic composites. Depending on the chemical concentrations, the flexural, tensile, and impact strengths of the modified flour filled HDPE composites were improved slightly, while the tensile and flexural moduli of the samples were increased significantly. The limiting oxygen index (LOI) levels of samples with modified wood flour were slightly improved, and succinic anhydride provided higher LOI levels compared to the samples with other anhydrides. This showed that the composites filled with chemically modified wood flour were slightly more thermally stable than control samples. It appears that wood flour modified with maleic, propionic, and succinic anhydrides can be successfully utilized as filler in polymer matrices.
The effect of DMDHEU modification on physical and biological properties of parallel strand lumbers
(Elsevier Sci Ltd, 2019) Kurt, Ramazan; Dizman Tomak, Eylem
In this study, the effect of dimethylol dihydroxyethyleneurea (DMDHEU) modification with four different concentration levels on several properties of parallel strand lumbers (PSLs) produced from poplar veneer strands with phenol and melamine formaldehyde adhesives was studied: density, moisture content, water absorption, thickness swelling, dimensional stability, wettability and decay resistance against C. puteana and T. versicolor attacks. Accelareted aging test was conducted in order to evaluate any loss in effectiveness in decay resistance and dimensional stability due to possibility of cleavage of adhesive bonds in lumbers in outdoors. The PSLs produced with modified strands presented higher density and dimensional stability related with their weight gain but lower moisture content, thickness swelling and water absorption than the controls. DMDHEU modification of PSLs was found efficacious in suppressing brown and white rot fungi attacks, but the protective effect was low when lumbers were aged. PSLs manufactured from rotary peeled veneer strands modified with 5% weight gain of DMDHEU and phenol formaldehyde adhesive showed the most promising results for the investigated properties. (C) 2018 Elsevier Ltd. All rights reserved.
Effect of process variations of polycaprolactone modification on wood durability, dimensional stability and boron leaching
(Walter De Gruyter Gmbh, 2019) Ermeydan, Mahmut Ali; Kartal, Zeynep Nur; Dizman Tomak, Eylem
In this study, in situ graft polymerization of epsilon-caprolactone (CL) was studied for its potential to limit boric acid (BA) leaching from wood, and to increase the dimensional stability and biological durability of wood against Coniophora puteana and Trametes versicolor fungi. For this purpose, CL monomer with/without BA was impregnated into wood, and the monomer was polymerized in wood cell walls using various methods and combinations of reactants. It was found that biodegradable polycaprolactone (PCL) grafting at high monomer concentrations could inhibit fungal degradation of wood cell walls, as well as improve the dimensional stability of wood up to 55% and reduce water uptake (WU) by about 50%. However, inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis revealed that in situ graft polymerization of CL is not an effective method to prevent BA leaching from wood.
Evaluation of dimensional stability, weathering and decay resistance of modified pine wood byin-situpolymerization of styrene
(Taylor & Francis Inc, 2020) Ermeydan, Mahmut Ali; Babacan, Mert; Dizman Tomak, Eylem
In this study, polystyrene modified Scots pine (Pinus sylvestrisL.) wood was investigated upon artificial weathering, decay resistance, dimensional stability and water uptake properties. Polystyrene modification was carried out on pretreated wood by immersion of wood into styrene monomer and further polymerization. The resistance of modified wood against cycles of UV and water exposures was examined by artificial weathering test for 672 hours, and decay resistance was evaluated by attacks ofConiophora puteanaandTrametes versicoloron the samples. During the artificial weathering, color and surface roughness of the samples, and macroscopic changes were determined periodically. Changes in the surface chemistry and morphology of the weathered samples were investigated by ATR-FTIR and SEM, respectively. It was proven that polystyrene effectively protected pine samples from both fungi even after leaching procedure, but it was more effective in preventingC. puteanaattacks thanT. versicolorattacks. As a result of artificial weathering, the surface of all samples was darkened. However, changes in color and roughness as well as crack formations of the modified sample surfaces were found less than those of the untreated samples. Polystyrene also provided considerable improvement on dimensional stability, as well as water repellence of wood.
An FT-IR study of the changes in chemical composition of bamboo degraded by brown-rot fungi
(Elsevier Sci Ltd, 2013) Dizman Tomak, Eylem; Topaloglu, Elif; Gumuskaya, Esat; Yildiz, Umit C.; Ay, Nurgul
The objective of this study was to use FT-IR analysis to investigate the chemical composition of aged and un-aged bamboo specimens, with and without node sections, decayed by brown-rot fungi. Specimens were exposed to two brown-rot fungi, Coniophora puteana and Poria placenta, for 8 weeks after which decay was assessed by weight loss and FT-IR spectra analysis. Depending on the bamboo section examined, the aging process reduced decay resistance of specimens. Weight loss (measured as a percentage) decreased from the top to the bottom portion of bamboo culms. The presence of nodes in the specimens increased weight loss caused by P. placenta attack, and caused only a slight increase in weight loss from C puteana attack. Significant chemical changes in bamboo were observed after fungal degradation, as revealed by FT-IR analyses. Consistent with the degradation mechanism of brown-rot fungi, lignin was essentially un-degraded or modified. Both brown-rot fungi caused a sharp decrease in the carbonyl absorption area. Surprisingly, cellulose peaks of degraded specimens were nearly similar to the peaks of control specimens. Aging treatments and biodegradation affected the crystalline structure of bamboo specimens. Poria placenta degraded wood components faster and changed the crystallinity more than C puteana did, in accordance with the weight losses due to decay. (C) 2013 Elsevier Ltd. All rights reserved.
Influence of tannin containing coatings on weathering resistance of wood: Combination with zinc and cerium oxide nanoparticles
(Elsevier Sci Ltd, 2018) Dizman Tomak, Eylem; Yazici, Omur A.; Şam Parmak, Ebru Devrim; Gönültaş, Oktay
In this study, influence of tannin containing coating combined with zinc and cerium oxide nanoparticles on color, gloss, surface roughness and macroscopic changes of Scots pine wood after artificial weathering was studied. For this purpose, 3 different tannin types, valex, mimosa and pine with various concentrations, 2 metal oxides, nano zinc and cerium oxide, and a water based transparent coating were used. Commercially available nano wood coating was used as a reference chemical. Results showed that wood surfaces got dark color, lost the initial gloss and become rougher after weathering of 1512h. Samples coated with tannin and nano metal oxide containing coatings exhibited better protection against degradation factors than reference and controls. Among the treatments, low concentration levels of tannins and cerium oxide were found to be more efficient on protection of wood surfaces in comparison to high concentration levels and zinc oxide. General condition of samples seemed to be better for mimosa and pine tannins for ZnO combinations, and valex and pine tannins for CeO2 combinations after the weathering test. Results of such a combination system clearly showed amount of expensive inorganic nanoparticles could be reduced with the addition of natural antioxidants into transparent coatings. (C) 2018 Elsevier Ltd. All rights reserved.
Influence of tannin containing coatings on weathering resistance of wood: Water based transparent and opaque coatings
(Elsevier Sci Ltd, 2018) Dizman Tomak, Eylem; Arican, Ferhat; Gönültaş, Oktay; Parmak, Ebru D. Sam
The aim of this study was to improve weathering resistance of Scots pine wood by treating the surfaces with water based transparent and opaque wood coatings containing valex, mimosa and pine tannins. Samples coated with tannin containing coatings with various concentrations were exposed to artificial weathering for 1512 h. Color, gloss, surface roughness and macroscopic changes were evaluated periodically during the test, and the results of coated samples were compared with controls. Visible surface degradations such as erosion, cracks and checks occurred on control samples while no crack formations were recorded for coated samples. Color measurement data showed that high concentration levels were needed for the least color change on the surfaces however concentration increase of tannins in the transparent coating affected surface gloss and roughness of samples negatively. The most promising tannin types in transparent coatings against the surface degradations were determined as valex and pine tannins. Opaque coating alone was found to be resistant against weathering factors, and the measurements clearly showed that there is no need to corporate any UV absorbers to this coating. (C) 2018 Elsevier Ltd. All rights reserved.
An investigation of surface properties of thermally modified wood during natural weathering for 48 months
(Elsevier Sci Ltd, 2018) Dizman Tomak, Eylem; Ustaomer, Derya; Ermeydan, Mahmut Ali; Yildiz, Sibel
Weathering period and exposure conditions can affect the degradation rate of wood surfaces. Longer weathering exposure periods are more reliable for end-use performance evaluations, and therefore it is desirable to investigate the role of long exposure periods on wood properties. This study aimed to investigate the effect of thermal modification on surface composition, roughness and color of ash, iroko, Scots pine and spruce wood species during natural weathering in East Black Sea Region of Turkey for 48 months. All measurements were performed at 6 month intervals. Regarding the results, surface roughness increased as the weathering period increased. Surface quality and color stability of the samples were enhanced with the thermal modification for all wood species, and those properties were much better for hardwoods than softwoods. FTIR data showed that changes in surface composition of thermally modified and unmodified wood were so high even at the first weathering exposure period. Thus, thermal modification may not be an effective protection method in long term outdoor conditions if the surface appearance and color stability is required.
KİMYASAL MODİFİKASYONUN ODUNDA SU ALMA, BOYUTSAL KARARLILIK VE BİYOLOJİK DAYANIMA ETKİSİ
(2014) Dizman Tomak, Eylem; Temiz, Ali
Bu çalışmada, asetik, fitalik ve propiyonik anhidritler ile modifikasyon işlemine tabi tutulan odunun su alma oranı, boyutsal kararlılık ve mantar çürüklüğüne karşı performansı araştırılmıştır. Bu amaçla sarıçam odunu (Pinus sylvestris L.) örnekleri anhidritler ile muamele sonrası 2, 4 ve 8 saat boyunca 120°C’de reaksiyona tabi tutulmuşlardır. Örneklerin kimyasal yapısındaki değişimler FT-IR ile, su alma oranı ve boyutsal kararlılıkları 14 gün boyunca yapılan ağırlık ve boyut ölçümleri ile, mantar çürüklüğüne karşı dayanımı ise bir esmer çürüklük mantarı olan Coniophora puteana’ya 3 ay maruz bırakılmasıyla belirlenmiştir. Mantar çürüklük testinde yıkanmış ve yıkanmamış örnekler kullanılmıştır. Elde edilen bulgulara göre; anhidritler ile modifiye edilen örneklerin su alma oranı kontrol örneklerine kıyasla oldukça düşük bulunmuştur. Boyutsal kararlılık bakımından en iyi sonuçlar sırasıyla propiyonik, asetik ve fitalik anhidritler ile elde edilmiştir. Mantar çürüklük testi öncesi yıkanma işlemine tabi tutulan ve tutulmayan kontrol örneklerinde C. puteana saldırısı sonrasında ağırlık kaybı sırasıyla %34 ve %37 bulunurken, anhidritler ile modifiye edilen ve çürüklük testi öncesi yıkanma işlemine tabi tutulmayan örneklerde ağırlık kaybı %0-2.1, yıkanma işlemine tabi tutulan örneklerde ise ağırlık kaybı %0.5-7.6 olarak bulunmuştur. Esmer çürüklük mantarına karşı dayanım açısından en iyi etkinlik propiyonik anhidritle modifikasyon işlemi sonrasında elde edilmiştir.
Limited oxygen index levels of impregnated Scots pine wood
(Elsevier, 2013) Dizman Tomak, Eylem; Cavdar, Ayfer Donmez
In this study, effect of various concentrations of boron powder, mixture of boric acid and borax, fireproof agent based on liquid blend of limestone, and silicon oil on limited oxygen index levels (LOI) of S. pine wood was investigated. Wood samples were first vacuum treated with the preservatives, and then were subjected to leaching procedure. Samples treated with fireproof agent showed the best results for improving the fire retardancy of wood, furthermore, samples treated with 25%, 50% and 100% of the solution did not burn. Leaching did not considerably change the LOI of wood samples treated with boron powder and silicon oil; however, LOI levels of samples treated with the mixture of boric acid and borax and fireproof agent were affected by leaching procedure probably arising those preservatives did not chemically bond to main wood components. All treatments improved fire retardancy of samples despite some amount of preservatives leached out from wood. (C) 2013 Elsevier B.V. All rights reserved.
Long-Term Leaching Effect on Decay Resistance of Wood-Plastic Composites Treated with Boron Compounds
(Springer/Plenum Publishers, 2018) Cavdar, Ayfer Donmez; Dizman Tomak, Eylem; Mengeloglu, Fatih
In this study, water absorption, thickness swelling and decay resistance of thermoplastic composites treated with three types of boron compounds was investigated. Spruce wood flour was treated with boric acid (BA), borax (BX) and mixture of BA-BX, and then was reinforced at two loading rate (20 and 40 wt%) in polymer matrix. Decay test of the composites was performed using with a brown rot fungus Coniophora puteana and a white rot fungus Trametes versicolor both for leached and unleached samples. The morphologic evaluations of decayed samples were done by scanning electron microscopy. Composites containing higher wood flour loading resulted in increased water absorption, thickness swelling, weight loss and moisture content. Fungal decay susceptibility of WPCs was influenced by leaching test for 60 days. Boron compound treated composites showed higher weight loss and moisture content than controls in decay test. All tested performance parameters were considerably increased in BX containing composites.
A methodological approach to epsilon-caprolactone modification of wood
(Taylor and Francis, 2022) Ermeydan, Mahmut Ali; Cambazoglu, Merve; Dizman Tomak, Eylem
Due to increasing environmental awareness, in recent years the research on classical wood preservation by hazardous impregnation chemicals has been shifted to more environmentally friendly chemical modification methods with organic molecules/polymers. The chemical modification processes rely on the replacement or blockage of wood hydroxyl groups with generally hydrophobic molecules, thereby improving the dimensional stability, water repellency and biological resistance of the wood. This study investigates in situ polymerization of epsilon-caprolactone to form poly(epsilon-caprolactone) (PCL), a biodegradable polymer, which was grafted to the wood cell walls of both Scots pine (Pinus sylvestris L.) and spruce wood (Picea orientalis L.). Wood modification by in situ polymerization of epsilon-caprolactone has been studied so far in order to be an alternative modification approach to obtain improved wood properties, such as good dimensional stability and improved water resistance without reducing mechanical properties considerably. In the light of previous studies, the current work proposes a methodological approach to epsilon-caprolactone modification in two aspects: (i) the effect of catalyst (tin(II) 2-ethylhexanoate) amount on wood properties (i.e., swelling (S), anti-swelling efficiency (ASE), water uptake (WU), mass loss (ML)) (ii) the effect of oven or solvent curing of epsilon-caprolactone on wood properties (i.e., S, ASE, WU, ML, compressive strength parallel to the grain, and chemical components). By these approaches, an optimum catalyst amount was determined, and an alternative method (oven-curing) which may be more economic by enabling the re-use of the waste chemical was evaluated in comparison to the method of epsilon-caprolactone modification in prior publications (solvent-curing).
A natural flavonoid treatment of wood: artificial weathering and decay resistance
(Springer, 2020) Dizman Tomak, Eylem; Ermeydan, Mahmut Ali
In this study, a natural flavonoid, chrysin, was used as a wood impregnation agent and evaluated in terms of artificial weathering and decay resistance of wood. For this purpose, Scots pine samples were impregnated with chrysin after tosylation pre-treatment and, then, exposed to artificial weathering for 672 h. Color, surface roughness, contact angle and macroscopic changes were recorded during the test period. Furthermore, surface chemical components and morphological changes were evaluated with ATR-FTIR and SEM, respectively. Decay resistance of samples was assessed using a brown-rot fungus (Coniophora puteana) and a white-rot fungus (Coriolus versicolor) for both leached and un-leached samples. In the results, chrysin impregnation was found efficacious in preventingC. puteanaattack. However, a proper protection was not ensured againstC. versicolorattack. Tosylation was effective in resisting decay by both fungi, but it was not effective in decreasing weathering degradation on the wood surface as chrysin impregnation did. Chrysin decreased color changes and surface roughness. In addition, surface hydrophobicity increased, and lignin degradation decreased with chrysin impregnation. Cracks on treated samples seemed to be an important disadvantage after exposure to weathering agents. Results of chrysin impregnation gave some promising results to improve service life of non/low-durable wood species in outdoor use.

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