Maderas-Cienc Tecnol http://revistas.ubiobio.cl/index.php/MCT <table> <tbody> <tr> <td style="width: 30%;"><strong><span style="color: #ffffff; text-align: center;"><img src="/public/site/images/visepul/22(4)2020.png"></span></strong></td> <td style="width: 30%;"> <div class="issueCoverDescription"> <div class="description"> <p><a href="https://scielo.conicyt.cl/scielo.php?script=sci_issuetoc&amp;pid=0718-221X20200050&amp;lng=es&amp;nrm=iso"></a></p> <p><img src="http://revistas.ubiobio.cl/public/site/images/visepul/pdf_icon_copy6.png" alt=""><a href="http://revistas.ubiobio.cl/index.php/MCT/issue/view/313">Full Text PDF</a></p> <p><img src="http://revistas.ubiobio.cl/public/site/images/visepul/e-book_full1.png" alt="">e-book version</p> <p><a href="http://revistas.ubiobio.cl/revistamadera/e-book/18.2-2016/mobile/"><img src="http://revistas.ubiobio.cl/public/site/images/visepul/mobile2.png" alt=""></a> mobile version</p> <p><a href="https://scielo.conicyt.cl/scielo.php?script=sci_issuetoc&amp;pid=0718-221X20190004&amp;lng=es&amp;nrm=iso"><img src="http://revistas.ubiobio.cl/public/site/images/visepul/logo_xml.png" alt="logo_xml.png"></a>&nbsp;<a href="https://scielo.conicyt.cl/scielo.php?script=sci_issuetoc&amp;pid=0718-221X20200050&amp;lng=es&amp;nrm=iso">XML</a></p> </div> </div> </td> <td style="width: 30%;"> <p>Editor-in-Chief: <a href="mailto:ananias@ubiobio.cl" target="_self">Rubén A. Ananias</a><span id="result_box" class="short_text" lang="en"><br>Technical Editor</span>: <a href="mailto:lsalvo@ubiobio.cl">Linette Salvo S.<br></a>Digital Manager: <a href="mailto:%20vsepulveda@ubiobio.cl">Victor Sepúlveda V.</a><br>E-mail :<a href="mailto:remaderal@ubiobio.cl">remadera@ubiobio.cl</a><br>E-mail :<a href="mailto:remadera.journal@gmail.com">remadera.journal@gmail.com</a><br><br>2019 Journal Impact Factors:<br> 2-years: 1.2<br>5-years: 1.3<br> Frequency: 4 issues by year.<br>January, April, July, October<br>ISSN 0718-221X online version.<br>ISSN 0717-3644 printed version.</p> </td> </tr> </tbody> </table> Universidad del Bio-Bio en-US Maderas-Cienc Tecnol 0717-3644 Thermal properties of Acacia mangium cross laminated timber and its gluelines bonded with two structural adhesives http://revistas.ubiobio.cl/index.php/MCT/article/view/4322 <p>The properties of CLT can be affected by the type of adhesives used. The thermal properties of the adhesive that joins the timber together is essential to determine the thermal endurance of the CLT product. In this study, two types of adhesives were used to join the cross laminated timber (CLT) manufactured from <em>Acacia mangium </em>namely phenol resorcinol formaldehyde (PRF) and one component polyurethane (PUR). The thermal properties of the adhesives, <em>A. mangium</em> wood and the gluelines were determined via Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA) tests. The TGA test showed that PRF adhesive had higher degradation temperature at 530 ˚C compared to PUR adhesive at 430 ˚C. Meanwhile, the PRF adhesive as a glueline in CLT also showed better thermal resistance where a higher amount of residue of 20,94 % was recorded at temperature up to 900 ˚C compared to PUR glueline with 18,26 % residue. The integrity of the CLT over temperature were determined via DMA test and the results showed that PRF adhesive as glueline had superior properties, indicating better interfacial bonding with the woods.</p> Norwahyuni Mohd Yusof Paridah Md Tahir Lee Seng Hua Fatimah Athiyah Sabaruddin Redzuan Mohammad Suffian James Mohd Asim Khan Lee Ching Hao Adlin Sabrina Muhammad Roseley ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Chemical variation of five natural extracts by non-polar solvent http://revistas.ubiobio.cl/index.php/MCT/article/view/4321 <p>Chemical compounds of wood preservation from plants vary and are not known specific to the species. Chemical analysis of plants is responsible to ensure active compound in natural extracts wood treatment. There are many sources of natural extracts found in Indonesia that were explored for wood preservatives chemicals. They are bark of acacia and alstonia, leaves of orthosiphon and azardirachta and Dioscorea tubers. The present study was aimed at investigating the variation of the chemical constituent of natural extracts material of wood preservative through GC-MS analysis. Five natural extract sources were acacia bark (<em>Acacia spp</em>.), pulai bark (<em>Alstonia scholaris</em>), kumis kucing leaves (<em>Orthosiphon spp</em>.), mimba leaves (<em>Azardirachta indica</em>), and gadung tubers (<em>Dioscorea spp</em>.). Two non-polar solvents, i.e., n-hexane and petroleum ether were used for five natural source extractions following ASTM soxhlet extraction. The research showed that triterpene and fatty acid derivatives were the major compounds present in five natural extracts. They were lupeol; 7,22-Ergostadienone; Lup-20(29)-en-3-one; Lup-20(29)-en-3-ol, acetate, (3.beta.)-; urs-12-en-3-one; ethanol,2,2-diethoxy-; stigmasta-5,22-dien-3-ol, acetate,(3.beta.)-; 5H-3,5a-Epoxynaphth(2,1-c)oxepin, dodecahydro-3,8,8,11a-tetramethyl-; linoleic acid; naphthalene, 1-methyl-. These compounds have been assigned as the possibly responsible to against termites or fungi.</p> T. A. Prayitno R. Widyorini G. Lukmandaru ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Energy gains of eucalyptus by torrefaction process http://revistas.ubiobio.cl/index.php/MCT/article/view/4364 <p>The aim of this study was to evaluate the changes in the characteristics of <em>Eucalyptus spp</em><em>. </em>from Paraíba Valley region, Sao Paulo - Brazil after torrification process. Torrification is a thermochemical process that occurs at temperatures lower than the pyrolysis process as a pretreatment to improve biomass characteristics for use as biofuel energy in power generation. An experimental study was carried out in a batch reactor at three temperatures (240 °C, 260 °C and 280 °C) with residence time of 30 and 60 minutes. At the indicated operating conditions by elemental analysis, higher heating value and thermogravimetric analysis were evaluated. Result showed that there was a reduction in the oxygen/carbon (O/C) and hydrogen/carbon (H/C) ratios, causing an increase in the thermal energy quality of torrified wood, about of 28 % and 47 % at temperatures of 260 °C with residence time of 60 minutes and 280 °C with 30 minutes, respectively. A thermogravimetric analysis showed that at 260 °C the hemicellulose was almost completely degraded leaving the fuel in better conditions for combustion or gasification processes.</p> Erica Leonor Romão Rosa Ana Conte ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Viability of wood decaying fungal mycelium after microwave radiation of bamboo culm http://revistas.ubiobio.cl/index.php/MCT/article/view/4375 <p>The present study was carried out to evaluate the effects of microwave (MW) radiation on viability of wood decaying fungi. The white rot (<em>Trametes versicolor</em>) and brown rot (<em>Rhodonia placenta</em>) fungi were grown on bamboo culm-samples. The mycelium growths were observed in controlled as well as microwave treated samples. The results showed that the viability of fungi decreased according to the applied MW time. This study proved the ability of the microwaves and exposure time MW3 (180 seconds) to kill the fungal colonies and do not allow for the growth of fungal spores, means the rate of growth of fungal colonies is inversely proportional to time of microwave exposure.</p> Pawan Kumar Poonia Shivaklara R Deepa Manish Kumar Anil Kumar ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Nanocellulose-reinforced phenol-formaldehyde resin for plywood panel production http://revistas.ubiobio.cl/index.php/MCT/article/view/4385 <p>The search for new technologies to improve adhesives and the properties of reconstituted wood panels is constant, and nanotechnology is a tool for this purpose. The aim of this study is investigating the effect of adding nanocellulose in the formulation of the adhesive phenol-formaldehyde on the physico-mechanical properties of <em>Pinus taeda </em>plywood panels. Three ratios of nanofibrillated cellulose (NFC) were added to the adhesive formulation used to produce plywood panels: 0,026 %, 0,038 % or 0,064 %. The panels were tested according to the European standards; apparent density, resistance to parallel and perpendicular flexure and glue line shear strength were determined after 6 hours of boiling and after the boiling cycle for the 1<sup>st </sup>glue line (face) and 2<sup>nd</sup> line (core). The use of NFC in the adhesive caused an increase of viscosity and reduction of the gel time of the adhesive. The apparent density of the panels was not influenced by the addition of NFC, but the properties of parallel bending, perpendicular flexing and glue line shear were sensitive to the addition of NFC. The NR2 treatment (0,038 % NFC) presented the best results in the mechanical tests.</p> Elaine Cristina Lengowski Eraldo Antonio Bonfatti Júnior Rafael Dallo Silvana Nisgoski Jorge Luís Monteiro de Mattos José Guilherme Prata ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 A new method for determining air permeabilities of wood-based panels http://revistas.ubiobio.cl/index.php/MCT/article/view/4386 <p>In this study, a new apparatus for measuring the air permeability of wood-based panel specimens without using water displacement was developed with the aim of decreasing the influence of variation in atmospheric pressure on permeability measurement. Validation experiments were conducted using plywood, oriented strand board (OSB), particleboard, and medium-density fiberboard (MDF) panels and a control specimen sealed with an epoxy resin. The background (leakage) flow of the apparatus was evaluated based on the experimental results of the control specimen. A methodology for the determination of air permeability based on Darcy’s law for gases and the evaluated background flow rate was proposed. The results of the current study were compared with those obtained in a previous study, indicating that the new method provides valid measurements for wood-based panels with high and low air permeability. No significant influence of variation in atmospheric pressure on the experimental results was observed, suggesting that the proposed method is suitable for a long-term continuous experiment for evaluating a specimen with extremely low permeability.</p> Takashi Tanaka ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Radial variation in cell morphology of melia azedarach planted in northern vietnam http://revistas.ubiobio.cl/index.php/MCT/article/view/4388 <p>The radial variation in cell morphology of ten-year-old <em>Melia azedarach</em> trees planted in northern Vietnam was experimentally investigated. The earlywood fiber lumen diameter and latewood fiber lumen diameter were almost unchanged from pith to 6th ring before significantly decreasing and remaining constant from 7th ring outwards. In contrast, fiber cell wall thickness in both earlywood and latewood increased from pith to 7th ring before becoming stable towards the bark. The maturation age of earlywood vessel lumen diameter estimated by segmented regression analysis indicated that wood of the <em>Melia azedarach </em>could be classified into core wood and outer wood, and the boundary between core and outer wood may be located at 7th ring from pith. This should be taken into account in wood processing using <em>M. azedarach</em> grown in northern Vietnam.</p> Doan Van Duong Laurence Schimleck Tai Tien Dinh Chu Van Tran ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Colorimetría de los tallos del bambú (Guadua angustifolia) en tres estados de madurez http://revistas.ubiobio.cl/index.php/MCT/article/view/4411 <p>El objetivo de este trabajo fue describir el color del tallo, también conocido como culmo, de <em>Guadua angustifolia </em>con el sistema colorimétrico CIE-L*a*b* y analizar la variabilidad entre los tres estados de madurez (joven, maduro y sobremaduro). El material de estudio se recolectó en la plantación de la empresa AGROMOD, ubicada en Reforma, Chiapas, México. Se tomaron 12 culmos de dos, cuatro y seis años, 36 en total, y se midió el color utilizando los parámetros del sistema CIE-L*a*b* con ayuda de un colorímetro digital. Posteriormente, se utilizó la metodología propuesta por CIE 2004 para obtener la variación total de color (∆E*) y medir la magnitud de la diferencia del color entre los tres estados de madurez. &nbsp;Como consecuencia de la madurez se observó un cambio secuencial de coloración en la parte externa del culmo, desde un verde claro, verde grisáceo, gris, hasta un tono café. Los valores de ∆E* fueron mayores de 20, lo que de acuerdo a los criterios de percepción de diferencia de color ∆E* indica que la variación del color entre un estado de madurez y otro puede clasificarse como “Muy grande”. Asimismo, al realizar un análisis de Kruskal Wallis en las coordenadas CIE-L*a*b* se encontró que la diferencia del color por edad es estadísticamente significativa (p &lt; 0,05).</p> Surisaddai Hernández López Francisco José Zamudio Sánchez Adriana Ávalos Vargas Gabriela Orozco Gutiérrez Amparo Máxima Borja de la Rosa ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Shear strength in friction welded joint of poplar wood impregnated with copper-based wood preservative http://revistas.ubiobio.cl/index.php/MCT/article/view/4440 <p>Environmentally friendly processes are of great interest and considerably needed due to the worldwide problem of pollution. Linear vibration welding of timber structural elements provides new opportunities to potentially achieve structural joints. Mechanically induced vibrational wood fusion welding is shown to be due mostly to the melting and flowing of some amorphous, cells-interconnecting polymer material in the structure of wood, mainly lignin, but also hemicelluloses. In this study, poplar (<em>Populus euramericana</em>) samples were impregnated with alkaline copper quat (ACQ) in order to enhance welding performance. Chemical changes of the impregnated and welded specimens were characterized by FT-IR techniques. A decrease in the proportion of unoxidized phenolic groups in the lignin were observed by FT-IR and the decreased joint strength observed is impregnated wood. After impregnation, shear strength decreased by 37 % to 54 %. The X-ray CT-scanning results revealed that the average density of the poplar wood (368 kg/m<sup>3</sup>) increased to 710 kg/m<sup>3</sup> by welding.</p> Mustafa Zor Ahmet Can ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Properties of thermally modified teakwood http://revistas.ubiobio.cl/index.php/MCT/article/view/4449 <p>Thermal modification is a treatment that seeks to improve the properties of wood and reduce the heterogeneity in its color. The objective of this work was to evaluate the effect of thermal treatment on the anatomical, chemical, physical, mechanical, colorimetric, and thermal stability properties of teakwood. For this, teakwood samples were treated by an industrial autoclave at final cycle temperature of 160 ºC. The reduction of cell wall thickness, the formation of cross-fissures and the crystallization of the wax inside the pores were observed in the anatomical structure. Chemically, the extractives evaporated and the polysaccharides ruptured, of which hemicellulose was the most affected. The heat treatment promoted lower equilibrium moisture, reducing the hygroscopicity and improving the dimensional stability of the wood. Considering the mechanical properties, the rupture modulus and the longitudinal and tangential hardness decreased after the heat treatment. The color of the wood changed significantly, from pink to dark brown. The treated wood had higher thermal stability, with greater weight loss at higher temperatures than the untreated wood.</p> Elaine Cristina Lengowski Eraldo Antonio Bonfatti Júnior Silvana Nisgoski Graciela Inês Bolzon de Muñiz Umberto Klock ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1 Physical and mechanical properties of wood from invasive tree species http://revistas.ubiobio.cl/index.php/MCT/article/view/4451 <p>Because invasive tree species are being suppressed all over the world, there is a lack of basic information needed for their use in the processing industry. One piece of important information for woodworking applications is the air-dry density, which is 653 kg/m<sup>3</sup> in the case of tree of heaven (<em>Ailanthus altissima</em>), 536 kg/m<sup>3</sup> for box elder (<em>Acer negundo</em>), and 702 kg/m<sup>3</sup> for green ash (<em>Fraxinus pennsylvanica</em>). The order of the 3 species is the same for oven-dry and basic density. In terms of compression and bending, tree of heaven has higher values than green ash. Because the strength of the tree of heaven and the green ash are largely the same as the common ash (<em>Fraxinus excelsior</em>), it can be replaced by these tree species. The properties of box elder wood are significantly different from those of</p> Komán Szabolcs David Varga ##submission.copyrightStatement## 2021-01-01 2021-01-01 23 1