Scielo RSS <![CDATA[Maderas. Ciencia y tecnología]]> vol. 18 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<strong>CONTRIBUCIÓN AL DESARROLLO DE LA INDUSTRIA MADERERA DE ALTO VALOR</strong>: <strong>FORTALECIENDO LAS CAPACIDADES HUMANAS CIENTÍFICAS Y TECNOLÓGICAS</strong>]]> <![CDATA[<strong>Effect of styrene maleic anhydride on physical and mechanical properties of recycled polystyrene wood flour composites</strong>]]> In this work, the influence of three types of styrene maleic anhydride (SMA) oligomers on the adhesion of polystyrene wood plastic composites (WPC) was investigated. The composites were processed on a twin-screw co-rotating extruder below 200°C using 20 wt% of wood flour. The styrene maleic anhydride with different content of maleic anhydride groups, 30%, 25% and 20% (w/w) and levels of 1, 2 and 4% of coupling agents (styrene maleic anhydride 2000, styrene maleic anhydride 3000 and styrene maleic anhydride EF40) in the composite formulations were tested. Mechanical, physical and morphologic properties were evaluated. The styrene maleic anhydride improves the compatibility of hydrophilic wood flour with hydrophobic polystyrene matrix. It has been observed that the addition of styrene maleic anhydride increased the wood plastic composites mechanical properties with the incorporation of 2% wt of styrene maleic anhydride 2000. The mechanical properties showed to be dependent on content of maleic anhydride in the coupling agent. Treated and non-treated wood plastic composites showed similar density values, but the void content was reduced for treated composites. Scanning electron microscopy revel the better adhesion between polymer and matrix when coupling agent were used. <![CDATA[<strong>Analysing the drying behavior of juvenile and mature </strong><em><b>Eucalyptus saligna</b></em><strong> wood in drastic drying test for optimal drying schedule</strong>]]> The heterogeneity of characteristics observed in the pith-bark direction within a log causes sawn pieces of wood have different behaviors during water removal. Understanding these differences is important for the industry regarding the possibility of classification of the lumber into juvenile wood and mature wood, facilitating the drying in separate loads. Thus, this study aimed to evaluate the behavior of juvenile and mature wood samples of Eucalyptus saligna when subjected to drastic drying. In order to do this, test specimens were submitted to drastic drying at 100°C to obtain the drying times, drying rates and dimensions of end checks. These data were applied in equations to obtain the parameters initial temperature, final temperature and drying potential, used in the elaboration of drying schedules. In juvenile wood we observed that the basic density was lower and the initial moisture content was higher. Mature wood showed a lower drying rate. Drying schedules were developed separately for juvenile and mature wood, the drying schedule for the latter considered milder than the drying schedule developed for juvenile wood. <![CDATA[<strong>Aggregate planning in forest harvest</strong>: <strong>A mathematical programming model and solution</strong>]]> En este estudio se propone y resuelve un modelo de programación entera mixta para la planificación táctica de la cosecha forestal. Se considera, el reemplazo de productos, la diferenciación de rodales y canchas de trozado. Las instancias usadas disponen de hasta: 60 rodales, 25 canchas de acopio, 10 clientes, 8 períodos de planificación y 20 reglas de trozado. Considerando, hasta 260000 variables, 4800 enteras y 10000 restricciones y usando el software Cplex. En todos los casos, se obtiene el óptimo y se verifica que a mayor número de reglas de trozado, el beneficio alcanzado también es mayor.<hr/>In this study, we propose and solve a mix Integer Programming model for the tactical planning in forest harvesting. The following elements we considered the replacement of products, the stand differentiation places of bucking. The instances used have: 60 stands, 25 stockyards, 10 customers, 8 planning periods and 20 bucking rules, with up to 260000 variables, 48000 integers and 10000 constraints. We used Cplex software and in all cases, we obtained the optimum and we verified that, when there are a greater number of bucking rules, the benefit achieved was also greater. <![CDATA[<strong>Natural durability of </strong><em><b>Cedrus atlantica</b></em><strong> wood related to the bioactivity of its essential oil against wood decaying fungi</strong>]]> The Atlas cedar, Cedrus atlantica is a resinous species of Pinaceae originated from North Africa and well known for its noble timber. This work was conducted to assess the natural durability of its wood, to study the chemical composition of essential oil extracted from its sawdust wood and to test the bioactivity of this essential oil against four wood decaying fungi: Gloeophyllum trabeum, Oligoporus placenta, Coniophora puteana and Trametes versicolor. The assessment of natural durability of wood was conducted according to the methods described in the European standards, CEN/TS 15083-1 and NF EN 350-1. Mass losses of wood specimens, after 16 weeks of exposure to fungi attack, in laboratory test, showed that Cedrus atlantica wood is very durable to durable against wood decay fungi attack. The extraction of essential oil from sawdust by hydro-distillation yielded about 3,35% and the chemical analysis of this essential oil by GC-MS showed that E-γ-Atlantone (19,73%); E-α-Atlantone (16,86%), 5-Isocedranol (11,68%); 9-iso-Thujopsanone (4,45%); Cedranone (4,13%) and Z α- Atlantone (4,02%) were the main major identified components. The antifungal activity tested by the direct contact technique on agar medium showed a strong inhibition of wood decaying fungi, especially Gloeophyllum trabeum inhibited at 1/1000 v/v concentration. <![CDATA[<strong>Mechanical parameters of thermally modified ash wood determined by compression in radial direction</strong>]]> Mechanical parameters of ash wood (Fraxinus excelsior) subjected to compression in radial direction, before and after its thermal modification and measured at moisture content close to the equilibrium moisture content of wood exposed in and outside (4 and 12%) were compared. Thermal modification of wood was performed at 190°C or 200°C for 2 h in industrial conditions. During the measurements, the moisture content of the modified and control samples was identical. The parameters compared included: modulus of elasticity, stress at proportionality limit, relative linear strain at proportionality limit and accumulated elastic energy. Changes in the mechanical parameters of wood induced by its thermal modification were found to depend on the modification temperature and wood moisture content. <![CDATA[<strong>Influencia de las dimensiones de la sección transversal sobre la resistencia a flexión en madera aserrada de </strong><em><b>Populus deltoides</b></em><strong> cultivado en Argentina</strong>]]> En el artículo se analiza el efecto de las dimensiones de la sección transversal sobre la resistencia a flexión en piezas de madera aserrada de Populus deltoides"Australiano 129/60" y "Stoneville 67", cultivados en el delta del río Paraná, Argentina. El programa experimental se llevó a cabo según las normas europeas sobre un total de 820 cuerpos de prueba separados en 5 muestras exhibiendo las dimensiones estructurales usuales. Los resultados mostraron que el aumento de la altura de la sección fue acompañado de una tendencia decreciente de la tensión de rotura en flexión, pero no permiten afirmar que esa relación está vinculada a la calidad de la madera. Se confirmó que puede despreciarse una correlación entre la resistencia y el ancho de la sección. El análisis puso en evidencia que la relación entre la altura de la sección y la resistencia del material investigado está adecuadamente expresada por el criterio europeo, el cual fue adoptado por la normativa de Argentina.<hr/>The present paper reports the results of an investigation regarding the study of size effects on bending strength in sawn timber of Argentinean Populus deltoides "Australian 129/60" and "Stoneville 67". An empirical research project with 5 samples containing a total of 820 specimens in usual structural sizes was carried out according to European standards. Results showed that strength decreases when depth increases but no clear influence of either the timber quality or the specimen thickness on size effects was found. The analysis evidenced that the European criterion -adopted by Argentinean standards- is suitable for considering the influence of depth on bending strength in the investigated species. <![CDATA[<strong>Decay resistance, thermal degradation, tensile and flexural properties of sisal carbon hybrid composites</strong>]]> Sisal-carbon hybrid composites were produced from mixtures having different weight ratios of sisal, carbon fibers and recycled polypropylene. All formulations were tested and evaluated for tensile and flexural properties. In addition, the thermal stability of the sisal-carbon hybrid composites were examined via thermogravimetric analysis and decay tests were conducted to determine the degradation of the hybrid composites. Results showed that the biological durability and mechanical and thermal properties improved with the increasing weight ratios of carbon fiber in the hybrid composites. According to the mechanical tests, the optimum hybrid composite formulation was found to be 12% sisal fiber + 28% carbon fiber + 60% rPP. <![CDATA[<strong>CO<sub>2</sub> adsorption on agricultural biomass combustion ashes</strong>]]> Carbon capture and storage has become an alternative means of confronting global warming. Further research and development into adequate and low-cost materials is required for CO2 adsorption technologies. Samples of fly ash, bottom ash and their respective pellets, produced from wheat bran combustion, were characterized and tested to assess their capacity for CO2 adsorption at different temperatures. Neither the ashes nor their pellets were subject to prior thermochemical activation. The bottom ash sample and its pellets showed a higher adsorption capacity for the majority of the temperatures studied. The pelletized bottom ash reached the maximum adsorption capacity (0,07 mmol CO2/g), followed by the non-pelletized bottom ash (0,06 mmol CO2/g); both at an adsorption temperature of 25°C. CO2 adsorption of bottom ash, from the combustion of wheat bran (agricultural biomass), by a physical adsorption mechanism was demonstrated whereas with the fly ash sample, CO2 adsorption by both physical and chemical adsorption mechanisms was identified. <![CDATA[<strong>Effect of weathering on physical and mechanical properties of hybrid nanocomposite based on polyethylene, woodflour and nanoclay</strong>]]> Wood plastic composites have received increasing attention during the last decades, because of many advantages related to their use. However the durability of Wood plastic composites after ultraviolet exposure has become a concern. In this research, hybrid nanocomposites of polyethylene and woodflour with different concentrations of nanoclay were fabricated using melt compounding followed by injection molding. Specimens were exposed for 2000 h to ultraviolet radiation and moisture cycling in a laboratory weathering device to simulate the effects of exposure to sunlight and rain. Physical and mechanical properties of the nanocomposites were evaluated, before and after weathering. The results indicated that the water absorption of wood plastic composites increased after weathering but nanoclay reduced the intensity of weathering to some extent, through decreasing of water absorption. Also results showed that weathering decreased modulus of elasticity values, however good dispersion of clay layers resulted in fewer drop of modulus of elasticity values. Fourier transform infrared spectroscopy showed that lowest carbonyl index is related to the nano wood plastic composites with 2wt% nanoclay. Also X-Ray diffraction patterns revealed that intercalation morphology has been formed for nano particles. <![CDATA[<strong>Hygroscopic properties following drying affects wood consumption by </strong><em><b>Odontotermes obesus</b></em>]]> The relationship between drying and hygroscopic ability of Crateva adansonii and Populus deltoides woods to resist feeding by Odontotermes obesus was studied. Woods were dried under the sun and in the oven for a range of 5-25 days and then these were exposed to termites for 25 days in underground pits in Randomized Complete Block Design pattern with five replications. Results showed that lowest moisture gain was observed at a short time for drying with each method. Weight loss after termites' exposure was more in less dried sap and heartwood of either plant species. The practical implication of these results is discussed. <![CDATA[<strong>Pine sawdust (</strong><em><b>Pinus arizonica</b></em><strong>) gasification in a fluidized bed reactor</strong>: <strong>Analysis of process variables</strong>]]> La gasificación hidrotérmica del aserrín de pino (Pinus arizonica) es un proceso de degradación termoquímica de sus macromoléculas poliméricas con el fin de producir principalmente hidrógeno y metano como biocombustibles. Este proceso puede ocurrir en un reactor de lecho fluidizado que permite un apropiado contacto gas-sólido, el adecuado manejo de la temperatura y una mayor velocidad de reacción. El propósito es modelar y simular las variables del proceso donde se gasifica esta biomasa forestal a partir del respectivo análisis de sensibilidad. Se obtiene que la conversión de reacción de gasificación del aserrín de pino crece a una temperatura mayor a los 900°C, presentando un comportamiento que tiende a ser isotérmico, por lo que se sugiere un proceso energéticamente autosostenible. A su vez, la reacción mejoró para una alimentación de aserrín de pino con un diámetro óptimo de tamaño de partícula de 0,65 mm; se ve favorecida para bajas relaciones de vapor de agua/biomasa alimentada alcanzando el óptimo en 2,375; y a bajas relaciones aire/biomasa con un valor óptimo de 0,289. Se evidencia que este proceso constituye una vía de aprovechamiento energético a partir de la conversión termoquímica de estos desechos y residuos forestales.<hr/>The hydrothermal gasification of sawdust pine (Pinus arizonica) is a process of thermochemical degradation of polymeric macromolecules in order to produce mainly hydrogen and methane as biofuels. This process can occur in a fluidized bed reactor which allows an appropriate gas-solid, proper temperature management and a faster reaction. The purpose is to model and simulate process variables where this forest biomass is gasified from the respective sensitivity analysis. It is obtained that the conversion of gasification reaction of pine sawdust increases at temperature higher than 900°C, showing a behavior that tends to be isothermal, suggesting an energetically self-sustaining process. In turn, it improved reaction for pine sawdust feed with an optimum particle size diameter of 0,65 mm; it is favored for low ratios steam / biomass fed in reaching the optimal 2,375; and at low air/biomass relationship with an optimum value of 0,289. It is evident that this process is a way of harnessing energy from thermochemical conversion of these wastes and forestry residues. <![CDATA[<strong>Applicability evaluation of </strong><em><b>Cupressus lusitanica</b></em><strong> for pulp production</strong>]]> This paper aimed to study Cupressus lusitanica wood tracheids biometrics along radial direction and chemical analysis in order to encourage the use of new forest species for pulp production in southern Brazil. Axial tracheids anatomical analysis was held in 3 positions, in the pith-periphery direction. Total length, total diameter and lumen diameter were analyzed, and wall thickness, flexibility coefficient, wall fraction, felting index and Runkel's ratio were calculated based on these variables. Chemical analysis determined total extractives, sodium hydroxide attack degree, ash, lignin and holocellulose content. For anatomical variables, a statistically significant increase in the pith-periphery direction was observed for total length (L = 5,85mm), for total diameter (D = 47,18µm), lumen diameter (d = 32,92µm) and wall thickness (e = 14,26µm) was observed stabilization from intermediate section. The species was characterized as with high rigidity tracheids (WF = 61,73%), although being considered "good" for wood pulp production (RI = 0,93). The chemical composition showed high lignin content (L = 36,21%) and low holocellulose content (H = 59,19%). Cupressus lusitanica wood showed appropriate anatomical characteristics to be part of the pulp industry raw material supply. However, chemical properties may compromise the species use due to high lignin content. <![CDATA[<strong>The effects of boron derivatives as pretreatment chemicals for biodegradation of sunflower stalks</strong>]]> This study examined the suitability of boron derivatives as pretreatment chemicals with regard to their efficiency in the enzymatic saccharification of sunflower stalks. It was hypothesized that the utilization of boron derivatives might improve enzymatic digestibility. The aim of this study was to examine the effect of NaOH and the boron derivatives sodium borohydride [NaBH4], calcined tincal [Na2B4O7(1-5)H2O], colemanite [CaB3O4(OH)3H2O], boron oxide [B2O3], borax decahydrate [Na2B4O(7)10H2O], disodium octaborate tetrahydrate [Na2B8O(13)4H2O] and boric acid [H3BO3] on enzymatic saccharification. Results showed that the boron derivatives prevented peeling reactions and preserved more glucan; however, the NaOH removed the highest amounts of xylan and lignin from the structure. Significant xylan removal was observed with H3BO3, while B2O3 was as effective as NaBH4 and NaOH for selective lignin removal. The highest enzymatic saccharification yield (59,5%) resulted with the 2% NaOH pretreatment, whereas slightly lower yields were achieved with some boron derivatives (1% NaBH4-45%; 2% B2O3-40,2%; and 2% H3BO3-36,7%). <![CDATA[<strong>Wood machining properties of Australian plantation-grown </strong><em><b>Eucalypts</b></em>]]> This study assessed the moulding, drilling, turning, sanding, and routing properties of seven plantation-grown hardwood species from southeast Australia to evaluate their potential as a resource for the manufacture of high quality furniture and furnishings. Eucalyptus grandis, Eucalyptus saligna, Corymbia maculata, Eucalyptus camaldulensis, Eucalyptus sideroxylon, Eucalyptus cladocalyx, and Eucalyptus globulus were machined using different tools, and the surface quality obtained was visually graded. A sanding sequence of 100-150 grit produced satisfactory surfaces for furniture manufacturing for most studied species. Usually, a feeding direction against the rotational direction of the tool showed best results and reduced incidence of corner breakout when routing. Overall, high-density plantation-grown Australian hardwood species performed well during machining trials with the use of appropriate parameters and cutting tools allowing overcoming some typical processing difficulties for some species. The data obtained within this study will allow optimising the machining process of plantation-grown wood in Australia and increase value from the current plantation resource. <![CDATA[<strong>Shape and cell wall slenderness effects on the stiffness of wood cell aggregates in the transverse plane</strong>]]> The present study investigates a homogenization method in the framework of finite element method to determine the effective stiffness properties of wood cell aggregates in the transverse plane. For this purpose, square and regular hexagonal representative volume elements are chosen to mimic the wood cells. Thereafter, simulation experiments are conducted to understand how different cell shapes and cell wall slenderness, which is cell wall thickness to height ratio, affect the stiffness properties in the transverse plane. The comparison between analytical and computational homogenization results show that square cells have higher elastic moduli than the ones computed for hexagonal cells whereas shear modulus of both cell shapes have more or less the similar values. This can be explained due to the effective deformation mechanisms under different loading conditions. Thus, the present study provides an effective stiffness estimation tool and insight for wood cell aggregates. <![CDATA[<strong>Effect of solvent and solvent-to-solid ratio on the phenolic extraction and the antioxidant capacity of extracts from  </strong><em><b>Pinus durangensis</b></em><strong> and </strong><em><b>Quercus sideroxyla</b></em><strong> bark</strong>]]> En la búsqueda de compuestos bioactivos de las plantas, la corteza de especies maderables es un subproducto promisorio, ya que contiene compuestos fenólicos de interés terapéutico. La extracción de estos metabolitos depende del disolvente que se utilice y de variables aplicadas en el proceso. Para un fin terapéutico, la medicina tradicional utiliza únicamente mezclas de etanol y agua. Se realizaron extracciones de la corteza de Pinus durangensis y Quercus sideroxyla, bajo un diseño experimental 2x3x3 para estudiar el efecto de soluciones hidroetanólicas 20, 50 y 80%, y la relación masa a extraer/volumen de disolvente 1/10, 1/20 y 1/30 sobre el rendimiento en sólidos, donde 28,72 ±0,9% correspondió a Pinus durangensis (PdE50-1/20) y 24,95±1,2% para Quercus sideroxyla (QsE50-1/30), la máxima concentración de fenoles totales se obtuvo con etanol 80%- 1/10 en ambas especies (PdE80-1/10 con 712,36±13,4 mg equivalentes de ácido gálico (GAE)/g) y QsE80-1/10 de 592,97±10,6 (GAE/g), mientras que la capacidad antioxidante evaluada mediante las técnicas de DPPH, ABTS y FRAP, mostró que PdE20-1/30 y QsE50-1/10, tuvieron la mayor actividad. Se encontraron diferencias estadísticas (p<0,05) entre los tratamientos aplicados. La concentración de etanol tuvo mayor efecto que la relación masa/volumen de extracción. Pinus durangensis contiene mayor concentración de fenoles y de flavonoides, respecto a Quercus sideroxyla, mientras que la cantidad de proantocianidinas es similar en ambas especies. Los flavonoides de Pinus durangensis son principalmente de tipo flavanona y flavonol, mientras que Quercus sideroxyla contiene ácido gálico y flavan-3-ol (catequinas).<hr/>Bark from timber species might be a promising target of therapeutical interest due to its content of bioactive, phenolic compounds. However, the extraction efficiency of these metabolites depends on the type of solvent chosen and the process variables analyzed. Traditional medicine only uses ethanol and water mixtures for therapeutical purposes. Therefore, in this study extractions of Pinus durangensis and Quercus sideroxyla bark were realized. In order to study the effect of the hydroethanolic solutions of 20, 50 and 80% and the relation mass/solvent volume ratio of 1/10, 1/20 and 1/30, an experiment design of 2x3x3 was followed, over the extract yield; where 28,72 ±0,9% corresponded to P. durangensis (PdE50-1/20) and 24,95±1,2% to Q. sideroxyla (QsE50-1/30). The highest content of phenolic compounds was obtained with ethanol 80%-1/10 in both species (PdE80-1/10 with 712,36±13,4 mg of gallic acid equivalent (GAE)/g) and QsE80-1/10 of 592,97±10,6 (GAE/g); while the antioxidant capacity evaluated through DPPH, ABTS and FRAP showed that PdE20-1/30 and QsE50-1/10 presented the strongest activity. Significant statistical differences (p<0,05) were found among the treatments analyzed. The ethanol concentration had a higher effect than the relation mass/solvent volume ratio. More importantly, P. durangensis showed the highest phenol and flavonoid concentration respect to Q. sideroxyla. However, the proanthocyanidin amount was similar in both species. Finally, the flavonoid content of P. durangensis is mainly composed by flavanone and flavonol type compounds, while Q. sideroxyla contains gallic acid and flavan-3-ol (catechins). <![CDATA[<strong>Surface wettability of Brazilian tropical wood flooring treated with He plasma</strong>]]> This study investigated the effect of plasma treatment on changes of surface wettability of wood flooring from two Brazilian tropical species, Hymenaea spp. (rode locus) and Tabebuia spp. (lapacho). Wood flooring samples were plasma treated at low pressure in a helium atmosphere. Energy level was set at 100 W and four glow discharge times (5, 15, 30 and 45 s) were tested. Changes in wettability were investigated by measuring apparent contact angle, droplet volume and spreading contact area. The results showed less susceptibility of lapacho wood to the plasma treatments, while reduction of apparent contact angle in rode locus wood reached up to 76% for longer discharge times. In general, discharge time of 15 s produced the same effect as discharge of 45 s on wettability, which is important for industrial applications. Visual analyses revealed increase of water droplet spreading on lapacho wood surface, even though the variation of spreading contact area was not significant. Plasma treatment is feasible to improve wettability of tropical woods. Nevertheless, these findings should be investigated further due to the intrinsic characteristics of woods from tropical species. <![CDATA[<strong>Effect of weathering on wood treated with tall oil combined with some additives</strong>]]> Growing interest on bio-based material has led to focus on environmentally benign wood treatment systems because of the environmental concerns. Tall oil is a by-product from pulp and paper industry, contains resin and fatty acids, and is biodegradable. Tall oil treated wood can provide some reduction in water uptake and increase in decay resistance. In this research crude tall oil was dissolved in ethanol at 5, 10 and 15 % concentrations in the treatment of Scots pine according to full cell process. Dyestuff, iron oxide and sodium ascorbate were used an additive as 0,5 %. Weathering performance of tall oil and tall oil combined with additives were investigated in accelerated weathering chamber by application of ultraviolet irradiation and water spray. It is taken for granted that increasing concentration results in higher weight percent gain in treated samples. The best results were obtained with 10 % tall oil and iron oxide which indicated minimum total color changes. Colour measurements and visual examination revealed that iron oxide was the most effective additive in reducing weathering effect and lowering the total colour change. <![CDATA[<strong>Wood under fresh water</strong>: <strong>Effect on the chemical properties and on decay resistance</strong>]]> This study aimed to evaluate the effect of waterlogging on the chemical properties and on decay resistance of two fast-growing eucalypt species. Samples of spotted gum and rose gum wood were placed underwater and taken out at different times: after 4, 8 and 12 months. Chemical properties were performed via wet chemical quantification (Tappi standards), monomeric sugars by HPLC, and qualitative evaluation of extractives by Py-GC/MS and ATR-IR spectroscopy; biological performance was investigated using Trametes versicolor and Gloeophyllum trabeum rot fungi. The results showed slight changes to the chemical properties of both wood species, with an increase in lignin represented by the reduction of sugars due to waterlogging. Both species showed higher susceptibility to Gloeophyllum trabeum mainly in the sapwood, with no influence on decay resistance due the waterlogging. <![CDATA[<strong>Preparation and characterization of nanofibrillated Cellulose/Poly (Vinyl Alcohol) composite films</strong>]]> Poly (vinyl alcohol) based composite films with different loadings of cellulose nanofibrils were prepared using a solvent casting method and their tensile, optical and wettability properties were tested. The morphology of both neat poly (vinyl alcohol) and nanocomposites was explored by using a field emission scanning electron microscope technique. Results indicated that the tensile strength and Young's modulus of poly (vinyl alcohol) composite films were significantly improved with the increase of cellulose nanofibrils loading. However, the percentage of elongation at break decreased with increasing of cellulose nanofibrils. The films became increasingly opaque with increasing cellulose nanofibrils contents, although the composites also retained moderate transparency. The samples containing cellulose nanofibrils exhibited higher hydrophobicity compared with that of neat poly (vinyl alcohol). Field emission scanning electron microscope micrographs revealed that the cellulose nanofibrils were homogeneously dispersed in the poly (vinyl alcohol) matrix.