Characterizing Star-sawn Pattern–Produced and Orthogonally Glued Specimens of Southern Pine

Abstract In this study, triangular specimens of southern pine (Pinus spp.; SP) generated by a star-sawn process were characterized according to knots and deformation. SP specimens were used to understand the differences among glue-line combinations of radial-to-radial, radial-to-tangential, and tangential-to-tangential faces bonded with phenol resorcinol formaldehyde resin. The specimens were tested for shear strength, dimensional stability, wood failure, and delamination rate in accordance with ASTM D1037 and D2559 standards. Among the star-sawn triangular samples studied, bows in tangential-face sections occurred the most. The radial-face sections of SP triangular specimens had more knots but a much lesser degree of deformation than the tangential-face sections. The tangential-to-tangential face glue-line samples showed a lower shear strength, more wood failure, and a greater tendency of delamination and dimensional change, especially when subjected to wet conditions. Confocal microscopic pictures revealed that the tangential-to-tangential glue line showed a greater tendency of deformation in the earlywood part and helped to explain the reason for poor glue-line durability and low shear strength. This article revealed that the star-sawn–process generated wood radial-face samples were more stable than others tested and are perhaps a good alternative for massive panel manufacturing.

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Effects of moisture content on lap-shear, bending, and tensile strength of lap-jointed and finger-jointed southern pine using phenol resorcinol formaldehyde and melamine urea formaldehyde

BioResources ◽

10.15376/biores.15.2.3534-3544 ◽

2020 ◽

Vol 15 (2) ◽

pp. 3534-3544 ◽

Cited By ~ 2

Author(s):

Jian Liu ◽

Kong Yue ◽

Feng Wang ◽

Jinhao Wu ◽

Zhongqiu Tang ◽

...

Keyword(s):

Tensile Strength ◽

Shear Strength ◽

Bending Strength ◽

Urea Formaldehyde ◽

Southern Pine ◽

Resorcinol Formaldehyde ◽

Bonding Performance ◽

Lap Shear ◽

Bonding Shear Strength ◽

Shear Bending

The bonding performance of the phenol-resorcinol-formaldehyde adhesive (PRF) and melamine-urea-formaldehyde adhesive (MUF) with southern pine as substrates at various moisture contents (MC) was evaluated. The results showed that bonding shear strength with MUF and PRF was negatively related to wood MC, and bonding shear strength with MUF was higher than that of the PRF. The bending and tensile strengths of finger-jointed lumber decreased with wood MC. The bending strength of finger-jointed lumber was affected more by wood than adhesive. However, both wood and adhesive exhibited the same important contribution to the tensile strength.

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SHEAR STRENGTH IN THE GLUE LINE OF Eucalyptus sp. AND Pinus sp.WOOD

Revista Árvore ◽

10.1590/0100-67622016000600017 ◽

2016 ◽

Vol 40 (6) ◽

pp. 1109-1117

Author(s):

Juliana Jerásio Bianche ◽

Angélica de Cássia Oliveira Carneiro ◽

João Paulo Silva Ladeira ◽

Ana Paula Mendes Teixeira ◽

Flávia Alves Pereira ◽

...

Keyword(s):

Shear Strength ◽

Glue Line ◽

Chemical Bonds ◽

Specific Load ◽

Resorcinol Formaldehyde ◽

Satisfactory Performance ◽

Eucalyptus Wood ◽

Load Tests ◽

Adhesive Effect ◽

Glued Joints

ABSTRACT To evaluate the adhesive efficiency on the union of glued joints in a particular temperature and humidity conditions for a specified time the adhesive must be submitted to specific load tests, such as shear in the glue line. The objective of this study was to evaluate the shear strength in the glue line of Eucalyptus sp and Pinus sp.woods. Five adhesives (castor oil, sodium silicate, modified silicate, , PVA and resorcinol-formaldehyde), three weights (150 g/m2, 200 g/m2, and 250 g/m2) and two species (Eucalyptus sp. and Pinus sp.) of wood were used. Twelve specimens were obtained from each repetition per treatment, corresponding to 108 specimens that were conditioned at a temperature of 23 ± 1°C and relative humidity of 50 ± 2%. The interaction between the weight and type of adhesive was significant for the shear strength in the glue line of eucalyptus wood. However, no interaction between the weight and the adhesive was found for pinus, only the isolated from the adhesive effect. Chemical bonds originated in the polymerization of resorcinol-formaldehyde adhesives and castor bi-component conferred upon these adhesives the greatest resistance in the glue line. Castor and resorcinol-formaldehyde adhesives showed the highest shear strength values in the line of glue and wood failure. Castor adhesive presented satisfactory performance for bonding of eucalyptus and pine woods.

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QUALITY OF PLYWOODS OBTAINED FROM Melia azedarach COMBINED WITH Pinus taeda, PRODUCED WITH UREA-FORMALDEHYDE AND PHENOL-FORMALDEHYDE RESINS

FLORESTA ◽

10.5380/rf.v44i1.30823 ◽

2013 ◽

Vol 44 (1) ◽

pp. 93 ◽

Cited By ~ 1

Author(s):

Setsuo Iwakiri ◽

Rosilani Trianoski ◽

Vinicius Gomes Castro ◽

Carlos Frederico Alice Parchen ◽

Roberto Daniel Araújo

Keyword(s):

Shear Strength ◽

Pinus Taeda ◽

Phenol Formaldehyde ◽

Urea Formaldehyde ◽

Glue Line ◽

Melia Azedarach ◽

Formaldehyde Resin ◽

Shear Tests ◽

Wood Veneer

AbstractThis study was developed to evaluate the quality of plywood produced from Melia azedarach in combination with Pinus taeda, glued with urea-formaldehyde resin (UF) and phenol formaldehyde (PF). Panels were produced using five veneers of Melia azedarach only, five veneers of Pinus taeda and also with faces made of Melia azedarach and core with Pinus taeda. The panels were evaluated by glue line shear tests and by static bending in parallel and perpendicular directions. The higher contents of extractives in Melia azedarach wood did not reduce the glue line shear strength between the layers. For both UF and PF glues, panels produced with veneers of Melia azedarach showed better results on static bending and glue line shear tests. The results indicate great potential of Melia azedarach wood in plywood production, both for internal use (UF), and for external use (PF).Keywords: Cinamomo; wood veneer; glue line. ResumoQualidade de painéis compensados de Melia azedarach em combinação com Pinus taeda produzidos com resina uréia-formaldeído e fenol-formaldeído. O objetivo deste trabalho foi avaliar a qualidade de painéis compensados de Melia azedarach em combinação com Pinus taeda, produzidos com resina ureia-formaldeído (UF) e fenol-formaldeído (FF). Foram produzidos painéis com todas as cinco lâminas de Melia azedarach e de Pinus taeda, e capas de Melia azedarach e miolo de Pinus taeda. Os painéis foram avaliados por meio de ensaios de cisalhamento da linha de cola e flexão estática paralela e perpendicular. Maiores teores de extrativos presentes na madeira de Melia azedarach não prejudicaram a resistência da linha de cola entre as lâminas. Tanto para a colagem uréica, quanto para a fenólica, os painéis produzidos com lâminas de Melia azedarach apresentaram melhores resultados nos ensaios de flexão estática e de cisalhamento da linha de cola. Os resultados obtidos indicam grande potencial da madeira de Melia azedarach para produção de painéis compensados, tanto para uso interior (UF), quanto para uso exterior (FF).Palavras-chave: Cinamomo; lâminas de madeira; linha de cola.

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A Resorcinol-Formaldehyde Resin as an Embedding Material for Electron Microscopy of Membranes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006355x ◽

1969 ◽

Vol 27 ◽

pp. 328-329 ◽

Cited By ~ 1

Author(s):

J. G. Robertson ◽

D. F. Parsons

Keyword(s):

Electron Microscopy ◽

Osmium Tetroxide ◽

Neutral Lipids ◽

Lipid Extraction ◽

Water Soluble ◽

Formaldehyde Resin ◽

Electron Microscope Autoradiography ◽

Resorcinol Formaldehyde ◽

Major Disadvantage ◽

Cell Organization

The extraction of lipids from tissues during fixation and embedding for electron microscopy is widely recognized as a source of possible artifact, especially at the membrane level of cell organization. Lipid extraction is also a major disadvantage in electron microscope autoradiography of radioactive lipids, as in studies of the uptake of radioactive fatty acids by intestinal slices. Retention of lipids by fixation with osmium tetroxide is generally limited to glycolipids, phospholipids and highly unsaturated neutral lipids. Saturated neutral lipids and sterols tend to be easily extracted by organic dehydrating reagents prior to embedding. Retention of the more saturated lipids in embedded tissue might be achieved by developing new cross-linking reagents, by the use of highly water soluble embedding materials or by working at very low temperatures.

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Influence of anatomy on the adhesion performance of four wood species

Research Society and Development ◽

10.33448/rsd-v9i4.2727 ◽

2020 ◽

Vol 9 (4) ◽

pp. e31942727

Author(s):

João Gabriel Missia da Silva ◽

Pedro Nicó de Medeiros ◽

Denise Ransolin Soranso ◽

Vinicius Peixoto Tinti ◽

José Tarcísio da Silva Oliveira ◽

...

Keyword(s):

Shear Strength ◽

Specific Gravity ◽

Wood Species ◽

Tectona Grandis ◽

Glue Line ◽

Anatomical Characteristics ◽

Ray Cells ◽

Adhesion Performance ◽

Adhesion Process

The aim of this study was to evaluate the influence of anatomical characteristics on the adhesion performance of Vatairea sp., Paulownia sp., Aspidosperma populifolium and Tectona grandis wood. Specimens for anatomical, physical and mechanical analyzes were produced from tangentially oriented boards. The treatments were joint glued from pieces of the same anatomical orientation (radial and tangential), evaluated for shear strength and glue line failure. The Vatairea sp wood had the highest specific gravity (0.74 g cm-3) and the Paulownia sp (0.34 g cm-3) wood was smaller. Aspidosperma populifolium species showed the highest shear strength in the glue line in the tangential and radial faces. The anatomical variables with higher influence on the wood adhesion process were pith ray cells and especially fibers that exhibit the greatest correlation with the shear strength of the glue line.

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Innentitelbild: Extension of The Stöber Method to the Preparation of Monodisperse Resorcinol-Formaldehyde Resin Polymer and Carbon Spheres (Angew. Chem. 26/2011)

Angewandte Chemie ◽

10.1002/ange.201103443 ◽

2011 ◽

Vol 123 (26) ◽

pp. 5894-5894 ◽

Cited By ~ 2

Author(s):

Jian Liu ◽

Shi Zhang Qiao ◽

Hao Liu ◽

Jun Chen ◽

Ajay Orpe ◽

...

Keyword(s):

Formaldehyde Resin ◽

Carbon Spheres ◽

Stöber Method ◽

Resorcinol Formaldehyde ◽

The Stöber Method

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Selected Properties of Parallel Strand Lumber Made from Southern Pine and Yellow-Poplar

Holzforschung ◽

10.1515/hf.2003.030 ◽

2003 ◽

Vol 57 (2) ◽

pp. 207-212 ◽

Cited By ~ 4

Author(s):

Y. Liu ◽

A.W.C. Lee

Keyword(s):

Compressive Strength ◽

Shear Strength ◽

Specific Gravity ◽

Moisture Content ◽

Dimensional Stability ◽

Modulus Of Rupture ◽

Southern Pine ◽

Yellow Poplar ◽

Average Modulus ◽

Parallel Strand Lumber

Summary This study was conducted to explore basic physical and mechanical properties of parallel strand lumber (PSL) made exclusively from southern pine and yellow-poplar, respectively, and to examine their relationships using statistical analysis. Small specimens were prepared from commercial southern pine PSL and yellow-poplar PSL billets and tested for specific gravity, moisture content, dimensional stability, bending properties, shear strength and compressive strength. Results indicate average specific gravity of southern pine PSL is higher than that of yellow-poplar PSL, while their average moisture content and dimensional stability are very similar. Southern pine PSL has higher average modulus of elasticity but lower average modulus of rupture than yellow-poplar PSL. While average longitudinal shear strength does not exhibit differences between southern pine PSL and yellow-poplar PSL, average compressive strength of southern pine PSL is higher than that of yellow-poplar PSL. There are positive correlations among modulus of elasticity, modulus of rupture and specific gravity. PSL improves some properties of solid wood from which PSL is made.

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Moisture Adsorption and Hygroexpansion of Paraffin Wax Emulsion-treated Southern Pine (Pinus spp.)

BioResources ◽

10.15376/biores.10.2.2719-2731 ◽

2015 ◽

Vol 10 (2) ◽

Cited By ~ 2

Author(s):

ThiThanh Chau ◽

Erni Ma ◽

Jinzhen Cao

Keyword(s):

Paraffin Wax ◽

Southern Pine ◽

Moisture Adsorption ◽

Pinus Spp

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Influence of coarse aggregate on shear resistance of self-consolidating concrete beams

Revista IBRACON de Estruturas e Materiais ◽

10.1590/s1983-41952017000100003 ◽

2017 ◽

Vol 10 (1) ◽

pp. 30-40

Author(s):

G. SAVARIS ◽

R. C. A. PINTO

Keyword(s):

Shear Strength ◽

Failure Modes ◽

Coarse Aggregate ◽

Concrete Beams ◽

Shear Resistance ◽

Self Consolidating Concrete ◽

Coarse Aggregates ◽

Lower Shear ◽

Nominal Size ◽

High Flowability

Abstract Self-consolidating concrete is characterized by its high flowability, which can be achieved with the addition of superplasticizer and the reduction of the amount and size of coarse aggregates in the concrete mix. This high flowability allows the concrete to properly fill the formwork without any mechanical vibration. The reduction in volume and particle size of the coarse aggregates may result in lower shear strength of beams due to a reduced aggregate interlock. Therefore, an experimental investigation was conducted to evaluate the influence of the reduction in the volume fraction and the nominal size of coarse aggregate on concrete shear strength of self-consolidating beams. Six concrete mixes were produced, four self-consolidating and two conventionally vibrated. A total of 18 beams, with flexural reinforcement but without shear reinforcement were cast. These beams were tested under a four-point loading condition. Their failure modes, cracking patterns and shear resistances were evaluated. The obtained shear resistances were compared to the theoretical values given by the ACI-318 and EC-2 codes. The results demonstrated a lower shear resistance of self-consolidating concrete beams, caused mainly due to the reduced aggregate size.

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