Effect of juvenile wood on strength properties and dimensional stability of black spruce medium-density fiberboard panels

Holzforschung ◽  
2005 ◽  
Vol 59 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jun Li Shi ◽  
Shu Yin Zhang ◽  
Bernard Riedl

Abstract Strength properties and dimensional stability of medium-density fiberboard (MDF) panels made from black spruce (Picea mariana [Mill.] BSP.) 0–20, 21–40, and over 40 year old fiber were studied. An analysis of covariance (ANCOVA) was performed to examine the differences in modulus of rupture (MOR), modulus of elasticity (MOE), and thickness swell (TS) of the three types of panels, while panel density was treated as a covariate in order to adjust the mean values that were partly attributed to panel density. The results indicate that MOR, internal bond (IB), and water absorption of MDF panels made from 0–20 year old fiber, which contained 100% juvenile wood, were significantly superior to those of panels made from 21–40 and over 40 year old fiber; but linear expansion (LE) of MDF panels made from 0–20 year old fiber was significantly larger than that of panels from the other two age classes. The differences in MOR, IB, water absorption, and LE between panels made from 21–40 and over 40 year old fiber were not significant. The comparisons of panel MOE and TS were relatively dependent on panel density due to existence of interactions among the three age groups.

2007 ◽  
Vol 37 (5) ◽  
pp. 866-873 ◽  
Author(s):  
Jun Li Shi ◽  
Bernard Riedl ◽  
James Deng ◽  
Alain Cloutier ◽  
S. Y. Zhang

Mechanical and physical properties of medium-density fibreboard (MDF) panels made from black spruce ( Picea mariana (Mill.) BSP) top, middle, and butt logs were studied. The analysis of variance and analysis of covariance were both performed to examine the impact of log position in the tree on panel modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), linear expansion (LE), thickness swell (TS), and water absorption. Results indicate that MOE and IB strength of MDF panels made from top and middle logs were significantly superior to those of panels made from butt logs; however, there was no significant difference in MOE and IB between panels made from top and middle logs. Water absorptions of top and middle log panels were significantly lower than that of panels made from butt logs, and the difference in water absorption between panels made from top and middle logs was not significant. TS of top log panels was the smallest among the panels from the three log positions in the tree and was significantly different from those of middle and butt log panels. TS of butt log panels was the highest, which was significantly different from that of top and middle log panels. The differences in LE among the panels made from top, middle, and butt logs were not significant. The comparison of MOR of top, middle, and butt log panels was dependent on panel density because of the interactions among the three groups. Top and middle log panels showed superior properties, because the thinner cell walls of fibres from top and middle logs resulted in an increased compaction ratio compared with the butt log panels. Panel density affected both panel MOR and MOE considerably; however, its impact on IB, LE, TS, and water absorption was not significant in this study. The equations describing the linear relationships between MOR, MOE, and panel density were developed.


BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3718-3733
Author(s):  
Osman Camlibel

Physical, mechanical, and formaldehyde emission properties were studied for medium density fiberboard (MDF) produced with oak (75%) and pine (25%) fibers that had been mechanically refined in the presence of calcite particles. The calcite slurry was prepared at two levels of solids, 1.5% and 3% (10 and 20 kg·m-³). Chips were cooked for 4 min at 185 °C, under 8 bar vapor pressure in an Andritz defibrillator. 1.8% liquid paraffin, 0.72% ammonium sulphate solution, and 11% urea-formaldehyde were added by percentage based on oven-dried wood fibers in the blowline at the exit of the defibrator. The fibers were dried to 11% moisture content. MDF boards (2100 mm × 2800 mm × 18 mm) were created using a continuous hot-press process. The addition of calcite in the course of MDF production resulted in improved physical properties, such as thickness swelling (ThS 24 hours) and water absorption (WA 24 hours). MDF boards prepared with calcite exhibited higher internal bond (IB), modulus of rupture (MOR), and modulus of elasticity (MOE). Resistance to axial withdrawal of screw also was increased by addition of 3% calcite. In addition, the lowest levels of formaldehyde emission were observed for MDF prepared with calcite at the 3% level.


2020 ◽  
Vol 4 (3) ◽  
pp. 609-614
Author(s):  
K. J. Lawal ◽  
A. Oluyege ◽  
T. S. Bola ◽  
K. S. Aina ◽  
B. C. Falemara ◽  
...  

This study investigated the dimensional stability and strength properties of plastic bonded composites produced from wood waste particles and polyethylene using extruder. The composites were produced from wood species such as such as: Triplochiton scleroxylon, Terminalia superba and Gmelina arborea at a mixing proportion of 60:40 (plastic/wood) on a weight by weight basis. Evaluation of properties was carried out in accordance with the American Standard Testing Methods of 570 and 790 to determine the dimensional stability and strength properties of the composites. The results of findings revealed that water absorption and thickness swelling of the wood composites ranged from 10.08% to 15.36% and 4.33% to 5.58% respectively after 24hours and 48hours immersion in water. Tensile strength also ranged between 29.4MPa and 45.6MPa. Composite board made from T. superba wood particles had the lowest significant water absorption (10.08%), thickness swelling (4.33%) and highest significant tensile strength (45.6MPa) compared to composites produced from G. arborea and T. scleroxylon wood particles. It was observed that high density wood species exhibit lower water intake, lower thickness swelling and higher tensile strength, while the contrary is the case for lower density wood species. In conclusion, the three tree species used for the study could be recommended for the production of wood composite like particle board, fibre board, wood cement boards and others.


Author(s):  
Jacob Mayowa Owoyemi ◽  
Hazzan Adigun

The increase in demand for wood for various purposes has put serious pressure on Nigeria’s forest with its attendant fall in the supply of solid wood for construction purposes. As an alternative, non-woody material like banana stem fibre is being investigated for the production of Cement Bonded Particle Board (CBPB). The sorption and strength properties of CBPB from Musa spp fibre were assessed. The board samples were formed using cement to materials mixing ration of 2:1 and 3:1 and blending proportions of sawdust and banana fibre using ordinary Portland cement as a binder. Physical and Mechanical properties of boards produced from stem using were investigated. The influence of blending proportion (B.P) and mixing ratio (MR) on Density, Water Absorption (WA), Thickness Swelling (TS), Linear Expansion, Modulus of Rupture (MOR), and Modulus of Elasticity (MOE) were determined. The results of sorption properties showed that for immersion at 24, 48, and 72 hours, WA, TS, and LE decreased with an increase in mixing ratio. MOE mean values ranged between 293.65 and 2367.01 N/mm2 for 2:1 and 250.99 and 2009.28 N/mm2 for 3:1 while MOR values ranged between 2.55 and 7.592 N/mm2 for 2:1 and ranged from 0.55 to 1.40 N/mm2 for 3:1 respectively. The result proved that banana fibre is suitable for the production of panel products with enhanced strength properties.


Wood Research ◽  
2021 ◽  
Vol 66 (5) ◽  
pp. 891-899
Author(s):  
TOMASZ OZYHAR

The addition of inorganic filler material in medium density fiberboard (MDF) and the effect on material properties as a function of particle size was examined. Medium density fiberboard was manufactured in a laboratory scale environment to a target raw densityof 750 kgm-3. Wood fibers were replaced by using calcium carbonate at 3 and 10 wt.% using fillers with weighted median particle sizes of d50= 2.0 μm and d50= 30 μm, respectively. Urea formaldehyde resin was used as binder in all MDF. The influence of filler addition on the modulus of elasticity, bending and tensile strength, dimensional stability and liquid permeability was investigated. The results demonstrate the effect of filler content and its dependence on particle size. The addition of filler with d50= 30 μm does not have any influence on material properties up to a filler content of 10 wt.%. Using the finer filler with d50= 2.0 μm at 10 wt.% filler, the quantity significantly increases the water adsorption and swelling behavior and reduces the strength properties of the MDF.


Holzforschung ◽  
2018 ◽  
Vol 72 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Min-Jay Chung ◽  
Sheng-Yang Wang

AbstractThe properties of oriented bamboo scrimber boards (OBSB) have been investigated at three density levels (0.8, 0.9, and 1.0 g cm3), while the boards were made from moso bamboo (Phyllostachys pubescens) grown in Taiwan (T-OBSB) and China (C-OBSB). A non-destructive technique (NDT), ultrasonic-wave velocity (Vu) measurements were applied and the dynamic modulus of elasticity (MOEdyn) was calculated. Moreover, static modulus of elasticity (MOE), modulus of rupture (MOR), profile density distribution, internal bond strength (IB), springback (SB), and dimensional stability were determined based on traditional methods. Positive linear relationships between density andVu, MOEdyn, MOE and MOR were observed, no matter if the measurements were done parallel (//) or perpendicular (⊥) to the fiber direction of the OBSBs. Moreover,Vu(//), MOEdyn,u(//), MOE(//), and MOR(//)were higher thanVu(⊥), MOEdyn,u(⊥), MOE(⊥)and MOR(⊥). C-OBSB had slightly lowerVu(//),Vu(⊥), MOEdyn,u(//)and DMOEu(⊥)values than T-OBSB. T-OBSB had higher MOE(//), MOE(⊥)and MOR(//)than C-OBSB, but less MOR(⊥). The profile density distribution of high-density T-OBSB showed singnificant data scattering. The profile density distribution of C-OBSB was homogeneous at all density levels. IB and SB data are directly proportional to density, but water absorption, thickness swelling and volumetric swelling are inversely proportional to density. T-OBSB has better bonding and strength properties, and dimensional stability than C-OBSB.


Author(s):  
Salman Salim ◽  
◽  
Mona Lena Abdul Aziz ◽  
Sufyan Abdullah ◽  
Mohamad Hairi Osman ◽  
...  

Bamboo is an evergreen plant native to Asia and America that grows at every altitude, even in unideal climate conditions. Betung bamboo or its scientific name Dendrocalamus Asper is one of the bamboo species that are easily found in peninsular Malaysia. This study examined the characteristics of Betung bamboo and its potential to manufacture chipboard. Several tests were conducted, namely modulus of elastic (MOE), modulus of rupture (MOR), thickness swelling (TS), and water absorption (WA) to evaluate the potential of Betung bamboo as the primary material in the manufacture of chipboard mixed with polyethylene as additive are the parameters considered. This study found that the composition of 70% bamboo and 30% polyethylene was produced optimum chipboard which met BS EN standards (British and European Standard). It was also found that the MOE and MOR values of the resulting chipboard exceeded the medium density board standards. For WA and TS values, the chipboard achieved the standard requirements. Thus, this study concludes that chipboard made of Betung bamboo with the addition of polyethylene is suitable to be applied for internal and external doors, and internal paneling for any commercial or domestic building and furniture.


2019 ◽  
Vol 43 (5) ◽  
Author(s):  
Morgana Cristina França ◽  
Alexsandro Bayestorff da Cunha ◽  
Caio Cesar Faedo de Almeida ◽  
Bruna Laís Longo ◽  
Willian Grubert

ABSTRACT The objective of this study was to evaluate the technical feasibility of producing particleboard from oversize resin fibers in a reduced proportion of adhesive. It was used as raw material, oversize resin fibers discarded from the MDF (Medium Density Fiberboard) production process, flake particles of Pinus spp. derived from an MDP (Medium Density Particleboard) company’s chipper and adhesive formed by the urea-formaldehyde resin and paraffin emulsion. The experiment consisted of five treatments, mixing particles and fibers in different proportions (100: 0%; 75: 25%; 50: 50%; 25: 75%; 0: 100%). Three panels were produced per treatment, with nominal density of 650 kg.m-3, 8% resin and pressing cycle of 160ºC, 40 kgf.cm-2 for 8 minutes. The properties of the panels were evaluated by the procedures described in ASTM D-1047 (1993), DIN 53362 (1982) and ABNT / NBR 14810 (2013). The results showed that oversize resin fibers have potential for use in the sector, especially in quantities above 75%, a fact that was evidenced by the values found for dimensional stability and strength/stiffness. For internal adhesion, the increase in the number of fibers above 25% was not significant.


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