The efficiency of Pistacia atlantica gum for increasing resistance of rapeseed oil-heat treated wood to fungal attacks

In this research, we used Pistacia atlantica gum during cooling phase of oil-heat treatment of poplar wood (Populus deltoids) to improve its resistance to the white-rot fungus Trametes versicolor and growth of the mold fungus Penicillium expansum. Thermal modification was carried out using rapeseed oil at 180 °C, 200 °C and 220 °C for 2 hours and 4 hours. The modified wood specimens were then directly cooled in the oil containing 0 %, 5 % and 10 % (w/w) of the gum at 25 °C for 30 minutes. The chemical constituents of the essential oil extracted with a Clevenger type apparatus were determined by chromatography–mass spectrometry (GC-MS). The amounts of α-pinene, β-pinene and α-terpinolene of the essential oil were 60,2 %, 8,7 % and 3,9 %, respectively. The mold resistance was greatly improved, while the improvement against the decay fungus was only observed for the specimens modified at 180 °C. Our results confirmed that the enhanced fungal resistance was not only due to the presence of monoterpenes in the essential oil, but also to a further reduction in the hygroscopicity of the treated wood

Preparation of Cellulose Nanocrystals from α-Cellulose and Optimization of its Isolation Conditions

Cellulose nanocrystals (CNC) are new class of cellulose materials that find wide applications in various research areas over the past two decades. These nanoparticles are usually made by acid hydrolysis of cellulose substances such as wood, cotton, Starch etc. The main aim of this study is to find the optimal conditions for obtaining an aqueous stable colloid suspension of cellulose nanocrystal (CNC) from α-cellulose with a high-yield procedure. Therefore various conditions of acid hydrolysis were evaluated as reaction temperature and reaction time. The percentage of yield was calculated for all suspensions. The morphology of the prepared CNC was characterized by Transmission Electron Microscopy (TEM), Environmental Scanning Electron Microscopy (ESEM) and the crystallinity was measured by X-ray diffraction (XRD). The results showed that highest yield of CNC (88%), was achieved from the reaction condition of 60 minutes at 60 °C. Generally, rod-like shape crystals achieved from α-cellulose with an average size of 35-50 nm and high crystallinity (92%) can be make it to a convenient and competitive source for the production of cellulose nanocrystal for various industries

Effect of severe lopping on radial growth of Lebanon Oak (Quercus libani Oliv.) trees in Baneh adjacent forests

One of the oldest traditional usages of forests is cutting the branches for fodder production. In Iran in some regions of northern Zagros some species specially Lebanon oak (Quercus libaniOliv.) is used to provide fodder. For this reason each family normally has a forest region to meet cattle's fodder and fuel wood by cutting tree branches. Since trees could record this phenomenon in their tree rings, in this study we tried to investigate the tree rings by using of Dendrochronology to understand the effect of human activity like cutting branches on tree rings formation. According to this idea, two stands of oak forests that located in regions near the village and regions that located in low human interruption (holly places like cemeteries) have been selected. Twenty thick and healthy trees were selected from each region and samples were taken in the shape of disks and increment cores. After preparing samples surface, ring width of the trees were measured by binocular and LINTAB measurement table with 0.01 mm precision. Cross dating have been done using TSAP software. Growth curves of trees in interrupted region showed significant growth reduction in comparison with growth curves of trees in preserved region. In addition, this type of usage of forests will change the normal growth form of the trees and will increase the negative pointer years as an index of the radial growth reduction in interrupted region. It looks that the severity of this traditional way of cutting branches is increased during the last 100 years

Propriétés de composites de polyéthylene haute densité et résidus de canne à sucre (effet de la délignification des fibres et d'un traitement de surface sur la résistance à la photo- et la bio-dégradation)

Les effets du vieillissement accéléré, comme la décoloration et la perte de propriétés mécaniques, limitent les utilisationsdes composites bois-polymère (WPC) dans les applications en extérieur. Dans la présente étude, il a été tenté d'étudier l'influence de l'utilisation de fibres délignifiées de bagasse (canne a sucre) en renfort sur les propriétés des WPC et de suivre leur effet sur le contrôle de la photo- et de la bio-dégradation (vis-à-vis des champignons et des termites). A côté des échantillons délignifiés, les effets d'une finition finition transparente ont également été étudiés sur la qualité de surface et la réduction des défauts causés par la photo- et la bio-dégradation d'échantillons pigmentés et non pigmentés. Afin de faciliter l'analyse des données et avoir des résultats plus fiables, des analyses statistiques ont été effectuées sur des données provenant de différentes techniques de mesure. Toujours dans cette étude, les effets positifs et négatifs de l'utilisation de pigments granulaires ont été étudiés. Les résultats ont montré que l'utilisation de fibres délignifiées, selon le type de solvant et le niveau de délignification, provoque des changements sur la qualité de surface et les propriétés mécaniques. En outre, les échantillons délignifiés ont montré une perte de rigidité comparés aux échantillons non-délignifiées. Après vieillissement, les échantillons délignifiés ne montraient pas de réduction du changement de couleur total causé par le vieillissement. Toutefois, les fibres délignifiées accompagnées de pigments entrainent, dans une certaine mesure, une stabilisation de la rigidité des échantillons exposés au vieillissement par rapport aux échantillons non-exposés.De plus, les échantillons avec la finition transparente ont montré des résultats très prometteurs. La finition réduit le changement de couleur total du au vieillissement, et un prétraitement de surface favorise le maintien de l'efficacité de la finition, dans toutes les étapes de la photo et la bio-dégradation. Par ailleurs, les échantillons délignifiés à 70% et les échantillons ayant subi un vieillissement montrent une plus forte biodégradation et une plus grande perte de masse par rapport aux témoins. L'étude métrologique montre que le test non-destructif par vibration est une méthode fiable pour étudier les propriétés mécaniques des WPC et les effets du vieillissement. Néanmoins, il n'a pas été montré d'effet important de la délignification sur le contrôle du vieillissement. Les études sur la corrélation entre les variables ont montré que les changements avant et après le vieillissement peuvent être prédits à partir des résultats de tests non-destructifs.The effects of weathering, such as color fading and loss in mechanical properties, limit the performance of wood-polymer composites (WPC) in outdoor applications. In the current study, it has been tried to investigate the influence of using delignified sugar cane bagasse fibers as a reinforcement on properties of WPC and follow the effects that it cause on controlling photo and bio-degradation (fungi and termite attacks). Beside delignified samples, the effects of clear coating also have been studied on surface quality and reduction of defects caused by photo and bio-degradations of pigmented and non-pigmented samples. To facilitate the data analysis and having more reliable results, some statistical analyses have been carried out on data from different variables. Also in this study the positive and negative effects of using granule pigments in master batch of components have been investigated. Results have shown that using delignified fibers, depending on type of solvent and level of delignification, cause changes on surface qualities and mechanical properties. As well, delignified samples have shown loss in MOE compare to non-delignified samples. After weathering, none of the delignified samples had reduced the total color change caused by weathering. However delignified fibers with pigments, to some extent, stabilized the MOE in weathered samples compared to un-weathered samples. In addition, clear coated samples have shown very promising results. Total color change was reduced in coated samples and by means of pre-treatments of surface, coating remained efficient in all steps of the photo and bio-degradations. This is while the 70% delignified samples and weathered samples showed higher degradation and weight loss compared to controls and un-weathered ones. Methodology investigation did show that vibration none-destructive test is the reliable method to study the mechanical properties of WPC and weathering effects. Nevertheless, it did not show the significant effects of delignification on controlling weathering. Studies on correlation between variables have shown changes before and after weathering which can be used in further studies on modeling.MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Evaluation of High Density Polyethylene composite filled with Bagasse after Accelerated weathering follow by biodegradation

Wood plastic composites (WPCs) have many applications as structural and non-structural materials. Adding wood flour to polymer will not only improve its mechanical properties, compared to net polymer, but also will lead to products with moldability characteristics. As the outdoor application of Wood Plastic Composites (WPCs) becomes more widespread, the resistance of these products against weathering, particularly ultraviolet (UV) light, and biodegradation becomes more of concern. In present study, composites from bagasse and high density polyethylene, with and without pigments, have been made through extrusion and gone through accelerated weathering for 1440h, then weathered and non-weathered samples were exposed to fungal and termite resistance tests. The chemical and surface qualities of samples were studied by means of ATR-FTIR spectroscopy, colorimetric, contact angle and roughness tests after weathering. After fungal and termite resistance tests, color changes and weight loss were observed. The results have indicated that using bagasse as filler can relatively reduce the discoloration of weathered samples. Moreover adding pigments into WPCs can reduce effects of weathering by reducing surface oxidation. However, it cannot affect the biodegradation after weathering. Despite of high resistance of samples against biological attack, weathering can enhance the termites and fungal attack on the surface and can cause surface quality loss

The Investigation of Acetylation and Anti-Oxidant Effect on Weathering of wood Plastic Composites By Means of FTIR and Color Metry (Color measurement)

In this study capability of acetylated poplar flour in manufacture of high density poly ethylene composite which expose to accelerated weathering, was investigated. The acetylation degrees at medium and zero (control) levels, use of anti- oxidant and duration of weathering were considered as variables and their effects on discoloration and photodegradation of WPC were investigated. To determine treatments influence on changes and color fade resulting from weathering, samples were tested after o, 250, 2000 hours of weathering. The results indicated that application of acetylated wood flour in WPC can reduce about 25% of weathering discoloration in short time and about 17% in long time. Also it shows that as exposed time of weathering increase Anti oxidant loss its effect. Although in short time it can reduce 12% of weathering color changes. FTIR results show that after 2000 h of weathering all peaks samples had same decrease which mean none of the treatments were useful. But Anti oxidant can reduce depth of weathering

Study on the potential use of nano-wollastonite to improve the fire resistance and dimensional stability of poplar wood (Populus nigra)

In this study possibility of nano-wollastonite uses for improving fire retardency of poplar wood (Populus nigra) was investigated. Also, water absorption and volumetric swelling of specimens were measured. Specimens for fire resistance were prepared according to ISO 11925 standard and for physical properties ASTM D4446-2002 standard. Specimens were impregnated with nano-wollastonite (NW), using full-cell process. Rate of concentrations were, 4, 6.3, 10 and 12 percent. Five fire-retarding properties were measured including: weight loss (%), ignition point (s), duration of flame after removing the burner (s), duration of glow after removing the burner (s), and carbonized area (%). The results showed that fire-retarding properties were increased with the NW-content. Furthermore, the treated wood specimens showed higher dimensional stability

The efficiency of pistacia atlantica gum for increasing resistance of rapeseed oil-heat treated wood to fungal attacks

In this research, we used Pistacia atlantica gum during cooling phase of oil-heat treatment of poplar wood (Populus deltoids) to improve its resistance to the white-rot fungus Trametes versicolor and growth of the mold fungus Penicillium expansum. Thermal modification was carried out using rapeseed oil at 180 °C, 200 °C and 220 °C for 2 hours and 4 hours. The modified wood specimens were then directly cooled in the oil containing 0 %, 5 % and 10 % (w/w) of the gum at 25 °C for 30 minutes. The chemical constituents of the essential oil extracted with a Clevenger type apparatus were determined by chromatography–mass spectrometry (GC-MS). The amounts of α-pinene, β-pineneand α-terpinolene of the essential oil were 60,2 %, 8,7 % and 3,9 %, respectively. The mold resistance was greatly improved, while the improvement against the decay fungus was only observed for the specimens modified at 180 °C. Our results confirmed that the enhanced fungal resistance was not only due to the presence of monoterpenes in the essential oil, but also to a further reduction in the hygroscopicity of the treated woo