scholarly journals Influence of Veneer Density on Plywood Thickness and Some Mechanical Properties

2021 ◽  
Vol 46 (341) ◽  
pp. 66-74
Author(s):  
Laimonis Kūliņš ◽  
Anete Meija ◽  
Rihards Roziņš ◽  
Kārlis Hermanis Liepa ◽  
Uldis Spulle
Keyword(s):  
Mechanical Properties ◽  
Symmetry Axis ◽  
Scientific Literature ◽  
Common Knowledge ◽  
Wood Fiber ◽  
Solid Wood ◽  
Wood Fibers ◽  
Tensile Shear ◽  
Wood Moisture ◽  
Direct Production

Abstract It has been common knowledge that as the density of wood increases, the mechanical properties also improve. In turn, the density of wood depends on many factors, including the wood moisture content, location and cross-section in the trunk, the type of treatment and the parameters of technological processes. There is a great deal of research reported in the scientific literature on the effect of solid wood density on mechanical properties for different wood species as well as for structural timber. However, no research data can be found related investigation of the influence of veneer density on the properties of the birch plywood. In the present study, researching the properties of 7-ply birch plywood (thickness 9 mm), it was concluded that as the density of veneers increases, the bending properties of plywood in the direction of wood fibers (covered veneers) increases. When determining the plywood gluing quality, similar tendencies have been observed. For plywood with a lower density in all veneer plies the gluing quality (tensile-shear test) for perpendicular wood fiber veneers increases in the direction from the symmetry axis or middle veneer to the plywood outer plies, which can be explained by the fact that the outer plies become denser at the time of the hot pressing process. The results of the study will allow birch plywood manufacturers in direct production, sort veneers by density, to produce plywood with very predictable gluing quality, plywood thickness and mechanical properties in bending.

Effect of the delignification of wood fibers on the mechanical properties of wood fiber–polypropylene composites

2006 ◽  
Vol 102 (5) ◽  
pp. 4759-4763 ◽  
Author(s):  
Alinaghi Karimi ◽  
Saleh Nazari ◽  
Ismaeil Ghasemi ◽  
Mehdi Tajvidi ◽  
Ghanbar Ebrahimi
Keyword(s):  
Mechanical Properties ◽  
Wood Fiber ◽  
Wood Fibers ◽  
Polypropylene Composites

Investigation of the Fracture of Resinated Single Wood Fibers in an Environmental Scanning Electron Microscope (Esem)

1998 ◽  
Vol 4 (S2) ◽  
pp. 838-839
Author(s):  
A. Egan ◽  
S. Shaler
Keyword(s):  
Mechanical Properties ◽  
Polymer Composite ◽  
Laser Scanning ◽  
Medium Density Fiberboard ◽  
Wood Fiber ◽  
Image Correlation ◽  
Environmental Scanning ◽  
Wood Fibers ◽  
Wood Polymer ◽  
Scanning Electron

Single fiber fracture is important in understanding the fundamental failure mechanisms in wood/polymer composite products such as medium density fiberboard (MDF). The mechanical properties and fracture behavior of individual wood fibers has only recently been observable using a combination of environmental scanning electron microscopy (ESEM), laser scanning confocal microscopy and digital image correlation (DIC). Previous work has shown that specific areas on the fiber such as microcompressions and pits acted as crack nucelators and induce a brash fracture across the surface of the fiber. Given the development of these procedures it is now possible to observe and measure the mechanical properties and fracture characteristics of the wood fiber/ polymer composite fibers.Individual black spruce wood fibers were coated with diphenylmethane 4-4'diisocyanate resin containing Hostasol Red GG. The addition of the Hostasol Red flurochrome provided the option of quantifying resin coverage by fluorescence microscopy.

scholarly journals A novel DOPO-g-KH550 modification wood fibers and its effects on the properties of composite phenolic foams

2018 ◽  
Vol 20 (2) ◽  
pp. 47-53 ◽  
Author(s):  
Yufeng Ma ◽  
Xiang Geng ◽  
Xi Zhang ◽  
Chunpeng Wang ◽  
Fuxiang Chu
Keyword(s):  
Mechanical Properties ◽  
Phenolic Resin ◽  
Wood Fiber ◽  
Treated Wood ◽  
Comprehensive Analysis ◽  
Wood Fibers ◽  
H Nmr ◽  
Interfacial Compatibility ◽  
Ft Ir ◽  
Diffraction Peaks

Abstract A novel 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) graft γ-amino propyl triethoxy silane (KH550) was synthesized and introduced on the surface of wood fiber. Finally DOPO-g-KH550 treated wood fiber (DKTWF) was used to prepare DKTWF composite phenolic foams (DKTWFCPF). The structures of DOPO-g- KH550 was acknowledged by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H-NMR). The structures of DKTWF were confirmed by FT-IR. Compared with wood fiber, the diffraction peaks’ position was basically unchanged, but the crystallinity was slightly increased and thermal stability were dramatically improved, T5% and Tmax increased by 21.9o and 36.1o respectively. But the char yield (800o) was slightly reduced. With the dosage of DKWF, there were different degrees of improvement including the mechanical properties, flame retardancy and microstructure of DKTWFCPF. Comprehensive analysis, the interfacial compatibility was significantly improved between DKTWF and phenolic resin, and the suitable content of DKTWF was 4%.

scholarly journals Sustainable Development of Hot-Pressed All-Lignocellulose Composites—Comparing Wood Fibers and Nanofibers

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2747
Author(s):  
Erfan Oliaei ◽  
Tom Lindström ◽  
Lars A. Berglund
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Lignin Content ◽  
Wood Fiber ◽  
High Yield ◽  
Wood Fibers ◽  
Cumulative Energy ◽  
Glass Fiber Composites ◽  
Sustainable Materials ◽  
Fiber Materials

Low-porosity materials based on hot-pressed wood fibers or nanocellulose fibrils (no polymer matrix) represent a new concept for eco-friendly materials with interesting mechanical properties. For the replacement of fossil-based materials, physical properties of wood fiber materials need to be improved. In addition, the carbon footprint and cumulative energy required to produce the material also needs to be reduced compared with fossil-based composites, e.g., glass fiber composites. Lignin-containing fibers and nanofibers are of high yield and special interest for development of more sustainable materials technologies. The present mini-review provides a short analysis of the potential. Different extraction routes of lignin-containing wood fibers are discussed, different processing methods, and the properties of resulting fiber materials. Comparisons are made with analogous lignin-containing nanofiber materials, where mechanical properties and eco-indicators are emphasized. Higher lignin content may promote eco-friendly attributes and improve interfiber or interfibril bonding in fiber materials, for improved mechanical performance.

Quantifying effects of compositional variations on microstructural properties of polypropylene-wood fiber composites by melt rheology and tensile test data

2018 ◽  
Vol 53 (4) ◽  
pp. 503-514 ◽  
Author(s):  
Ali Durmus ◽  
Mehmet Ozcan ◽  
Ismail Aydin
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Wood Fiber ◽  
Micromechanical Model ◽  
Viscoelastic Behavior ◽  
Alkaline Treatment ◽  
Fiber Composites ◽  
Test Machine ◽  
Wood Fibers ◽  
Compositional Variations

In this study, melt-state rheological behavior and solid-state mechanical properties of polypropylene-wood fiber composites were investigated in detail depending on compositional variations such as (i) alkaline treatment on wood fibers, (ii) fiber size, (iii) wood fiber content, and (iv) compatibilizer/wood fiber ratio. Composite samples were prepared in a lab-scale co-rotating twin screw extruder by using a maleic anhydride grafted polypropylene as compatibilizer. Morphological features of composites were examined in a scanning electron microscopy. Viscoelastic behavior and mechanical properties of samples were analyzed by performing oscillatory tests in a rotational rheometer and a universal tensile test machine. It was found that the increasing amounts of wood fiber and compatibilizer/wood fiber ratio led to improve melt elasticity and tensile strength. It was concluded that the amount of compatibilizer into composite formulation was the most important compositional parameter compared to size and chemical treatment of wood fibers for improving the physical properties of composites. The Nicolais-Nicodemo micromechanical model showed that the increasing amount of compatibilizer yielded lower parameters which implied better interfacial adhesion between polypropylene and wood fibers.

scholarly journals Thermo-Mechanical Properties of a Wood Fiber Insulation Board Using a Bio-Based Adhesive as a Binder

Buildings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 152
Author(s):  
Franz Segovia ◽  
Pierre Blanchet ◽  
Nicolas Auclair ◽  
Gatien Geraud Essoua Essoua
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Citric Acid ◽  
Crude Glycerol ◽  
Wood Fiber ◽  
Physical And Mechanical Properties ◽  
Acid Mixture ◽  
Wood Fibers

The goal of the present study was to develop a low-density thermal insulation board using wood fibers and a bio-based adhesive as a binder, which was prepared from a crude glycerol and citric acid mixture. The physical and mechanical properties of insulation boards manufactured using two ratios of crude glycerol and citric acid (1:0.66 and 1:1 mol/mol) and two adhesive contents (14% and 20%) were evaluated. The results show that the insulation boards with a range of density between 332 to 338 kg m−3 present thermal conductivity values between 0.064 W/m-K and 0.066 W/m-K. The effect of adhesive content was very significant for certain mechanical properties (tensile strength perpendicular to surface and compressive strength). The tensile strength (internal bond) increased between 20% and 36% with the increased adhesive content. In contrast, the compressive strength decreased between 7% and 15%. The thermo-mechanical properties obtained of insulation boards such as thermal conductivity, traverse strength, tensile strength parallel and perpendicular to surface, and compressive strength are in accordance with the requirements of the American Society for Testing and Materials C208-12 standard for different uses. The results confirm the potential of crude glycerol and citric acid mixture to be used as an adhesive in the wood fiber insulation boards’ manufacturing for sustainability purposes.

Study on Mechanical Properties of Wood Fiber/Polypropylene Composites

2010 ◽  
Vol 123-125 ◽  
pp. 1195-1198 ◽  
Author(s):  
Alireza Ashori
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Sample Preparation ◽  
Coupling Agent ◽  
Wood Fiber ◽  
Wood Fibers ◽  
Polypropylene Composites ◽  
Fiber Loading ◽  
Four Levels ◽  
Properties Of Composites

In this study, the effect of wood fiber concentrations on the mechanical properties of composites, prepared by using MAPP as the coupling agent, was investigated. In the sample preparation, four levels of fiber loading and three compounding temperatures were used. Most major changes in composite performance occurred at fiber contents above 30 wt%.The results clearly showed that the fiber loading of 30 and 40 wt% at 190oC was provided adequate reinforcement to increase the tensile and flexural strength of the PP powder. The modulus also increased with increasing the fiber content, because poplar fibers are believed to be more rigid than polymer. However, the addition of wood fibers resulted in a decrease in elongation and impact properties of the composites.

scholarly journals Correlation between Mechanical Properties and Processing Conditions in Rubber-Toughened Wood Polymer Composites

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1170 ◽  
Author(s):  
Valentina Mazzanti ◽  
Lorenzo Malagutti ◽  
Andrea Santoni ◽  
Francesca Sbardella ◽  
Andrea Calzolari ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wood Flour ◽  
Wood Fiber ◽  
Sharp Decrease ◽  
Processing Conditions ◽  
Wood Fibers ◽  
Screw Speed ◽  
Feeding Mode ◽  
Wood Polymer ◽  
The Cost

The use of wood fibers is a deeply investigated topic in current scientific research and one of their most common applications is as filler for thermoplastic polymers. The resulting material is a biocomposite, known as a Wood Polymer Composite (WPC). For increasing the sustainability and reducing the cost, it is convenient to increase the wood fiber content as much as possible, so that the polymeric fraction within the composite is thereby reduced. On the other hand, this is often thwarted by a sharp decrease in toughness and processability—a disadvantage that could be overcome by compounding the material with a toughening agent. This work deals with the mechanical properties in tension and impact of polypropylene filled with 50 wt.% wood flour, toughened with different amounts (0%, 10%, and 20%) of a polypropylene-based thermoplastic vulcanizate (TPV). Such properties are also investigated as a function of extrusion processing variables, such as the feeding mode (i.e., starve vs. flood feeding) and screw speed. It is found that the mechanical properties do depend on the processing conditions: the best properties are obtained either in starve feeding conditions, or in flood feeding conditions, but at a low screw speed. The toughening effect of TPV is significant when its content reaches 20 wt.%. For this percentage, the processing conditions are less relevant in governing the final properties of the composites in terms of the stiffness and strength.

scholarly journals Morphology and Mechanical Properties of 3D Printed Wood Fiber/Polylactic Acid Composite Parts Using Fused Deposition Modeling (FDM): The Effects of Printing Speed

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1334 ◽  
Author(s):  
Teng-Chun Yang ◽  
Chin-Hao Yeh
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Fused Deposition Modeling ◽  
Wood Fiber ◽  
Wood Fibers ◽  
Surface Color ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Printing Speed ◽  
Morphology And Mechanical Properties

In this study, a wood fiber/polylactic acid composite (WPC) filament was used as feedstock to print the WPC part by means of fused deposition modeling (FDM). The morphology and mechanical properties of WPC parts printed at different speeds (30, 50, and 70 mm/s) were determined. The results show that the density of the printed WPC part increased as the printing speed decreased, while its surface color became darker than that of parts printed at a high speed. The printing time decreased with an increasing printing speed; however, there was a small difference in the time saving percentage without regard to the dimensions of the printed WPC part at a given printing speed. Additionally, the tensile and flexural properties of the printed WPC part were not significantly influenced by the printing speed, whereas the compressive strength and modulus of the FDM-printed part significantly decreased by 34.3% and 14.6%, respectively, when the printing speed was increased from 30 to 70 mm/s. Furthermore, scanning electronic microscopy (SEM) illustrated that the FDM process at a high printing speed produced an uneven surface of the part with a narrower width of printed layers, and pull-outs of wood fibers were more often observed on the fracture surface of the tensile sample. These results show that FDM manufacturing at different printing speeds has a substantial effect on the surface color, surface roughness, density, and compressive properties of the FDM-printed WPC part.

Sign in / Sign up

Export Citation Format

Share Document