scholarly journals PHYSICAL AND MECHANICAL PROPERTIES OF ORIENTED WOOD-CEMENT BOARDS PRODUCED WITH FIVE EUCALYPTUS SPECIES

FLORESTA ◽  
2017 ◽  
Vol 47 (3) ◽  
Author(s):  
Thiago Souza da Rosa ◽  
Vinícius Rosa Schweitzer ◽  
Rosilani Trianoski ◽  
Setsuo Iwakiri
Keyword(s):  
Mechanical Properties ◽  
Pinus Taeda ◽  
Eucalyptus Grandis ◽  
Physical And Mechanical Properties ◽  
Eucalyptus Species ◽  
Mass Ratio ◽  
Specific Mass ◽  
Eucalyptus Saligna ◽  
Pure Species ◽  
Species Mixture

This study aimed to manufacture oriented wood-cement boards using five Eucalyptus species and mixture between then, to compare the effect of the particles orientation, and to evaluate the physical and mechanical properties according to competent standards. The species studied were: Eucalyptus benthamii, Eucalyptus dunni, Eucalyptus grandis, Eucalyptus saligna, Eucalyptus urograndis the mixture between them and the Pinus taeda as control.  The bonding agent employed was commercial grade Portland cement types CP II-Z-32R. The panels had dimensions of 48 x 48 x 1.2 cm and nominal specific mass of 1.2 g/cm³. The cement/wood/water mass ratio used was 2.5:1:1 and 2% of CaCl2 by weight of cement was used as an additive. The orientation of strands did not influence the dimensional stability properties. All boards had very low IB strength, being that, none treatments reached the requirements to internal bond of competent standards. The MOR and MOE results indicated that species mixture can be obtained boards with properties similar to pure species. In general, the boards showed low mechanical strength what can be attributed to particles geometry and wood-cement ratio. The wood of Eucalyptus species presents potential for use in cement-wood panels.

scholarly journals EFFECT OF THERMO-MECHANICAL TREATMENT ON PROPERTIES OF PARICA PLYWOODS (Schizolobium amazonicum Huber ex Ducke)

2017 ◽  
Vol 41 (1) ◽  
Author(s):  
Mírian de Almeida Costa ◽  
Cláudio Henrique Soares Del Menezzi
Keyword(s):  
Mechanical Properties ◽  
Mechanical Treatment ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
Modulus Of Rupture ◽  
Thermal Treatments ◽  
Mechanical Compression ◽  
Specific Mass ◽  
Thermo Mechanical Treatment ◽  
Temperature And Pressure

ABSTRACT Thermo-mechanical treatment is a technique for wood modification in which samples are densified by means of heat and mechanical compression, applied perpendicularly to fibers, which under different combinations of time, temperature, and pressure increases wood density and thus improve some of its properties. This study aimed to treat thermo-mechanically parica plywood and observe the effects on its physical and mechanical properties. Specimens were submitted to two treatments, 120 and 150 ºC, remaining under pressure for seven minutes and, subsequently, under zero pressure for 15 minutes. Results showed a significant increase in specific mass from 0.48 g cm-3 to an average of 0.56 g cm-3, and a compression ratio of about 31.7% on average. Physical properties also varied significantly and results showed that treated samples swelled and absorbed more water than those untreated, leading to a greater thickness non-return rate. This indicates the proposed thermal treatments did not release the internal compressive stress generated during panel pressing, not improving its dimensional stability as a result. On the other hand, mechanical properties were positively affected, leading to an increase of 27.5% and 51.8% in modulus of rupture after treatments at 120 and 150 ºC, respectively. Modulus of elasticity and glue-line shear strength did not vary statistically and Janka hardness was 29.7% higher after treatment at 150 ºC.

scholarly journals COMPORTAMIENTO DE LA MADERA DE Pinus taeda IMPREGNADO CON ARSENIATO DE COBRE CROMATADO (CCA)

FLORESTA ◽  
2005 ◽  
Vol 35 (1) ◽  
Author(s):  
Teresa María Suirezs
Keyword(s):  
Mechanical Properties ◽  
Pinus Taeda ◽  
Physical And Mechanical Properties ◽  
Mechanical Resistance ◽  
Burnett Method ◽  
Pinus Taeda L ◽  
American Society ◽  
Positive Effect ◽  
Copper Arsenic

Este trabajo tuvo por objetivo, estudiar el comportamiento de las propiedades físicas y mecánicas de la madera de Pinus taeda L. impregnada por vacío-presión con preservador CCA (CrO3; CuO; As2O5) con tres retenciones, 5, 10 y 15 kg/m3. El proceso de impregnado se realizó, por el método Burnett, aplicándose presión y vacío de 7 kg/m2 y – 0,5 kg/m2 respectivamente. Los ensayos de las propiedades físicas y mecánicas se determinaron según lo establecen, las Normas técnicas IRAM (Instituto Argentino de Racionalización de Materiales), ASTM (American Society for Testing and Materials) y DIN (Deutsche Industrie Norm). Las propiedades físicas como ser los pesos específicos aparentes no son afectadas por las retenciones de CCA en la madera. Las contracciones tanto en el sentido tangencial como radial en las maderas impregnadas son menores. Las propiedades mecánicas de resistencia a la flexión estática, compresión paralela a las fibras, tracción perpendicular a las fibras, disminuyen levemente sus valores promedios con respecto a la madera sin impregnar, pero estas diferencias no son estadísticamente significativas, para 95 % de confianza. La impregnación ha producido un efecto positivo en la dureza Janka transversal y en el corte paralelo a las fibras tangencial siendo estas diferencias estadísticamente significativas. Behaviour of the wood of Pinus taeda impregnated with Chrome, Copper, Arsenic (CCA) Abstract The physical and mechanical properties of the wood of Pinus taeda L. without impregnating and impregnating by empty - pressure with preserving CCA (Chrome, Copper, Arsenic) with three retentions, 5, 10 and 15 kg/m3 have been determined and analysed. The impregnation was accomplished in an autoclave applying the Burnett method. The physical and mechanical properties were determined according to the following technical Procedures; IRAM (Argentine Institute for Rationalization of materials), ASTM (American Society for Testing and Material) and DIN (Deutsche Industrie Norm). The results indicate that the specific weights of samples containing different percentages of humidity was not affected by the retentions of CCA in the wood. The shrinkage both in the tangential and radial directions in the impregnated samples were smaller in the impregnated sample. The mechanical resistance to statics flexion, compression parallel to the fibers, traction perpendicular to the fibers, hardness tangential and radial Janka and paralell radial cut, do not show statistically meaningful differences between impregnated and not impregnated samples; however the treatment has produced a positive effect in the hardness transverse Janka and in the parallel cut to the tangential fibers.

scholarly journals INFLUENCE OF DRYING ON THE PHYSICAL AND MECHANICAL PROPERTIES OF WOOD FROM TREES GROWN IN AN AGROFORESTRY SYSTEM

2020 ◽  
Vol 44 ◽  
Author(s):  
Elder Eloy ◽  
Eduarda Bandera ◽  
Tauana Mangini ◽  
Laura da Silva Zanchetta ◽  
Rômulo Trevisan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Eucalyptus Grandis ◽  
Physical And Mechanical Properties ◽  
Agroforestry System ◽  
Bending Test ◽  
Schizolobium Parahyba ◽  
Standard Specimens ◽  
Forced Air ◽  
Air Circulation

ABSTRACT The cultivation of native and exotic species intercropped in an agroforestry system raises the interest for information on the properties of wood. Therefore, different methods are being tested to improve the technological properties of this material, including drying, which causes changes in the physical and mechanical properties of the wood. The present study investigated the influence of drying on the physical and mechanical properties of wood from tree species grown in an agroforestry system. Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis W. Hill × Eucalyptus urophylla S.T. Blake (hybrid), and Schizolobium parahyba (Vell.) S.F.Blake were the species selected for the study. Three 9-year-old individuals of each of the species were obtained from an agroforestry system. Thirty wood samples (2.5 × 2.5 × 41 cm) were extracted from each species. The wood samples were divided between temperature treatments; 6 samples were used for each heat treatment (control, 120, 150, 180, and 210 °C), which were then dried for two hours in an oven (with forced air circulation). Following the heat treatment, the mechanical properties of wood samples were evaluated to determine the modulus of elasticity and rupture, the tension in the proportional limit, and maximum force according to the ASTM D-143-94 (2000) standard. Finally, the physical properties of the retractability of the wood samples were evaluated according to the NBR 7190 (ABNT, 1997) standard. Specimens used to analyze this variable came from sections of the wood (sample dimensions: 2.5 × 2.5 × 5 cm) not affected by the static bending test. Our findings indicate that, for all species investigated in this study, drying alters the physical and mechanical properties of the wood, with the most significant changes occurring at temperatures between 120 and 180 °C.

ANATOMICAL, PHYSICAL AND MECHANICAL PROPERTIES OF TRANSGENIC LOBLOLLY PINE (PINUS TAEDA L.) MODIFIED FOR INCREASED DENSITY

2019 ◽  
Vol 51 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Z D Miller ◽  
P N Peralta ◽  
P H Mitchell ◽  
S S Kelley ◽  
V L Chiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Physical And Mechanical Properties ◽  
Pinus Taeda L

Comparison of Physical and Mechanical Properties in Ceramics Composites Si3N4–CTR–AlN and Si3N4–Y2O3–AlN

2005 ◽  
Vol 498-499 ◽  
pp. 381-387
Author(s):  
Sandro Aparecido Baldacim ◽  
Olivério Moreira Macedo Silva ◽  
Claudinei dos Santos ◽  
Cosme Roberto Moreira Silva
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Yttrium Oxide ◽  
Elevated Temperatures ◽  
Physical And Mechanical Properties ◽  
Ceramic Materials ◽  
Powder Materials ◽  
Sintering Aids ◽  
Specific Mass ◽  
Processing Cost

The important factor to consider for successful ceramics composites development is the need of matching the whiskers and matrix characteristics, taking into account the chemical compatibility of the sintering aids utilized. The purpose of this work was to analyze and compare use of rare earth concentrate (CTR) and yttrium oxide, as sintering aids, and its influence in the densification and physical/mechanical properties of hot pressed and sintered Si3N4-SiC(w). The CTR powder materials present high yttrium oxide percentage and its production is cheaper than the additives usually used in ceramic materials, such as Y2O3. For physical and mechanical properties evaluation, specific mass, crystalline phases, micrographs analysis, microhardness and fracture toughness were measured, showing similar results between the two sintering aids. Therefore, this study shows the possibility of obtaining low processing cost products with the use of rare earth concentrate. Meanwhile, more characterization steps are necessary for analyzing its behavior at elevated temperatures.

Wood grain angles variations in Eucalyptus and their relationships to physical-mechanical properties

Holzforschung ◽  
2020 ◽  
Vol 74 (12) ◽  
pp. 1089-1097
Author(s):  
José Clailson Franco Coelho ◽  
Graziela Baptista Vidaurre ◽  
João Gabriel Missia da Silva ◽  
Maria Naruna Felix de Almeida ◽  
Ramon Ferreira Oliveira ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Eucalyptus Grandis ◽  
Basic Density ◽  
Physical And Mechanical Properties ◽  
Wood Properties ◽  
Volumetric Shrinkage ◽  
Angular Deviation ◽  
Grain Angle ◽  
Strength And Stiffness ◽  
The Relationship

AbstractThe relationship between grain angle and wood properties has not been focus of researches in wood industry. The aim of this study was to establish grain angle variations in commercial Eucalyptus logs and their effects on physical-mechanical wood properties. Wood maximum angular deviation (MAD) was correlated with density, volumetric shrinkage, compressive strength parallel to grain, flexural strength and stiffness as determined by bending and acoustic methods in wood of seven Eucalyptus grandis × Eucalyptus urophylla clones at 13 years old. The relationship between MAD at pith-bark and base-top positions and its effect on the physical and mechanical properties were evaluated. Amplitude of MAD values was small for the seven clones, and the mean was 6.2°. The grain deviation decreased by only 8% in base-top direction, and the correlations among MAD and three logs heights were small and negative (r = −0.13). MAD values presented an increasing trend of 33% in pith-bark direction, with a small positive correlation (r = 0.42). Basic density (BD) presented a significant correlation with the MAD (r = 26). There was no significant correlation between the MAD and volumetric shrinkage, mechanical properties and modulus of elasticity dynamic (determined by stress wave timer, ultrasound or transverse vibration).

scholarly journals Optimization of properties of Eucalyptus oriented strand boards by specific gravity of panels

2018 ◽  
Vol 24 (2) ◽  
Author(s):  
Thiago Souza da Rosa ◽  
Rosilani Trianoski ◽  
Setsuo Iwakiri ◽  
Ghislaine Miranda Bonduelle ◽  
Claudiney Do Couto Guimarães
Keyword(s):  
Mechanical Properties ◽  
Specific Gravity ◽  
Pinus Taeda ◽  
Inverse Relationship ◽  
Linear Models ◽  
Oriented Strand Board ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Eucalyptus Species

This study aimed to determine the influence of specific gravity on properties of oriented strand boards produced with five Eucalyptus species and get linear models between the properties and the densification of the panels. The species studied were: Eucalyptus benthamii, E. dunni, E. grandis, E. saligna, E. urograndis and the mixture between them. The panels were produced with phenol formaldehyde resin and nominal densities of 0,65 g/cm³ and 0,75 g/cm³. The water absorption has an inverse relationship to the density of the panel. The relation between mechanical properties and specific gravity of the panel is directly proportional. The panels produced with the Eucalyptus species showed better properties than those produced with control species (Pinus taeda), except for tensile perpendicular. By means of linear models obtained in this study conditions for each species, it can estimate the specific gravity to produce oriented strand board panels that adequate the standard requirements.

scholarly journals Propriedades físico-mecânicas da madeira de Chrysophyllum marginatum

2016 ◽  
Vol 36 (86) ◽  
pp. 135 ◽  
Author(s):  
Jussan Albarello de Cezaro ◽  
Rômulo Trevisan ◽  
Rafaelo Balbinot
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Elasticity Modulus ◽  
Basic Density ◽  
Physical And Mechanical Properties ◽  
Eucalyptus Saligna ◽  
Longitudinal Contraction ◽  
Bottom Up ◽  
Bending Resistance ◽  
Anisotropic Coefficient

Esse estudo objetivou avaliar as propriedades físico-mecânicas da madeira de Chrysophyllum marginatum (Hook. e Arn.) Radlk. Foram utilizadas três árvores com 20,3 ± 6 cm de diâmetro. Por regressão, determinou-se a variação no sentido base-topo de retratibilidade, coeficiente anisotrópico, teor de umidade saturado e massa específica básica. Para caracterizar a flexão estática na primeira tora, nas condições úmida e seca ao ar, foi realizada análise de variância pelo teste de Tukey. Observou-se decréscimo das contrações radial e tangencial e da massa específica básica da madeira no sentido base-topo, inversamente ao teor de umidade saturado, que apresentou uma variação crescente. Na análise do coeficiente anisotrópico, verificou-se uma tendência de acréscimo até 1,30 m de altura, seguido de estabilização a partir dessa posição até o topo. A contração longitudinal apresentou tendência de decréscimo até, aproximadamente, 40% de altura, seguido de acréscimo até a altura de inserção do primeiro galho vivo. As médias do coeficiente anisotrópico e da massa específica básica foram 2,3 kg m-3 e 594 kg m-3, respectivamente. A condição de umidade seca ao ar apresentou maior resistência à flexão estática do que quando saturada e os valores dos módulos de elasticidade e de ruptura foram semelhantes aos encontrados em estudos de Eucalyptus saligna e Carya illinoinensis.Physical and mechanical properties of Chrysophyllum marginatum woodThis study aimed to evaluate the physical and mechanical properties of the wood of Chrysophyllum marginatum (Hook. And Arn.) Radlk. We used three trees with 20.3 ± 6 cm of diameter. It was determined by regression analysis the variation bottom-up of shrinkage, anisotropic coefficient, saturate moisture content and basic density. To characterize the static bending in the first log, in saturate and air dried conditions, it was performed variance analysis using Tukey›s test. It was observed a decrease in radial and tangential contractions and basic density on bottom-up direction. Saturate moisture content increased, considering the same direction. Anisotropic coefficient presented increase tendency up to 1.30 m height followed by stabilization from that position to the top. It was observed decreasing tendency of longitudinal contraction to approximately 40% of total height, followed by increasing up to the insertion of the first living branch. Mean anisotropic coefficient and basic density were 2.3kg m-³ and 594 kg m-³, respectively. Air dry condition showed greater static bending resistance than when saturate. Values of rupture and elasticity modulus were similar to those found in studies with Eucalyptus saligna and Carya illinoinensis.Index terms: Shrinkage; Anisotropic coefficient; Static bending

Pulping-tailored fiber properties from a novel Brazilian Eucalyptus hybrid

Holzforschung ◽  
2014 ◽  
Vol 68 (3) ◽  
pp. 273-282 ◽  
Author(s):  
Marcelo Coelho dos Santos Muguet ◽  
Fernando José Borges Gomes ◽  
Kyösti Ruuttunen ◽  
Leena-Sisko Johansson ◽  
Anna-Stiina Jääskeläinen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Lignin Content ◽  
Eucalyptus Grandis ◽  
Physical And Mechanical Properties ◽  
Pulp Fibers ◽  
Fiber Properties ◽  
Thermomechanical Pulping ◽  
Bulk Chemical

Abstract The chemical composition and morphology of pulp fibers have a significant impact on the properties of fiber products. Pulp samples from a novel unique Eucalyptus triple hybrid [Eucalyptus grandis × (Eucalyptus urophylla × Eucalyptus globulus)] were obtained by various pulping processes – kraft, soda-anthraquinone (NaOH-AQ), and thermomechanical pulping (TMP). The chemical composition of the fiber surfaces was evaluated by X-ray photoelectron spectroscopy (XPS). The surface lignin content of NaOH-AQ pulp fibers was lower than that of the kraft counterpart. However, kraft pulp handsheets showed better physical and mechanical properties. XPS data strongly suggests that together with the pulp bulk chemical composition the xylan is more abundant on the surface of kraft fibers, which is reflected on their better mechanical properties. Moreover, the relatively low surface lignin content in TMP pulp compared to wood suggests that defibration takes place in the secondary wall, where lignin is less concentrated.

Sign in / Sign up

Export Citation Format

Share Document