Composite wood products
Abolfazl Kargarfard
Abstract
The of utilization corn stalk residues in combination with poplar wood for particleboard production is investigated. Four combinations of corn stalk and P.nigra particles (100% corn stalk; 75% corn stalk, 25% poplar wood; 50% corn stalk, 50% poplar wood and 25% corn stalk, 75% poplar wood) is used. Two ...
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The of utilization corn stalk residues in combination with poplar wood for particleboard production is investigated. Four combinations of corn stalk and P.nigra particles (100% corn stalk; 75% corn stalk, 25% poplar wood; 50% corn stalk, 50% poplar wood and 25% corn stalk, 75% poplar wood) is used. Two resin contents of 10 and 12% and two press temperatures of 170 and 180C is employed.
The results showed that increasing press temperature from 170 to 180C, decreased both MOR and MOE of boards and increasing resin content from 10 to 12%, improved MOR. When the ratio of poplar wood to corn stalk increases, both MOR and MOE of the boards increases and the highest values were reached at 50 and 75% poplar wood. Higher press temperature and lower ratio of corn stalk improved internal bond (IB). Higher press temperature, resin content and lower ratio of corn stalk, decreased thickness swelling. Based on the results, with application of either 25 to 50% corn stalk and press temperature of 170C, standard particleboard can be produced.
Composite wood products
Abolfazl Kargarfard
Abstract
Abstract: The application of corn stalks in the production of oriented strand board (OSB) is investigated. Corn stalks strands were produced in three sizes of 50, 75 and 100 millimeters length and dried to reach 2% moisture content. Oriented strand boards were made using either urea formaldehyde, melamine ...
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Abstract: The application of corn stalks in the production of oriented strand board (OSB) is investigated. Corn stalks strands were produced in three sizes of 50, 75 and 100 millimeters length and dried to reach 2% moisture content. Oriented strand boards were made using either urea formaldehyde, melamine formaldehyde and phenol formaldehyde resin, and two press temperatures of 175 and 185 ° C. OSB boards using poplar wood strands, 100 millimeters long were also produced as control samples. The results of strength measurements of the boards were statistically analyzed using factorial experiment and completely randomized block design. The grouping of the averages was based on Duncan Multiple Range Test. The results showed that the effect of the resin type on the flexural properties and internal bonding of the boards is statistically significant and boards produced using phenol formaldehyde resin exhibited the lowest modulus of rupture, modulus of elasticity and internal bonding strength. However, the adhesive type did not statistically influence the physical properties. The strand length also statistically influenced the board strength properties and boards made using poplar strands showed higher strength compared to corn stalks strands. The thickness swelling of the poplar OSB was almost twice the values of corn stalks OSB but the water absorption of these boards was lower than of corn stalks OSB. Press temperature adversely affected the modulus of rupture and elasticity, but higher press temperature improved the internal bonding strength. Higher press temperature increased the physical properties of the boards.
Abolfazl Karegarfard
Abstract
The objective of this investigation was the utilization of corn stalk in Medium Density Fiberboard (MDF) production. Therefore 27 laboratory MDF boards were produced using three press temperatures of 165, 175 and 185 °C and three press duration of 3, 3.5 and 4 minutes. The mechanical and physical ...
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The objective of this investigation was the utilization of corn stalk in Medium Density Fiberboard (MDF) production. Therefore 27 laboratory MDF boards were produced using three press temperatures of 165, 175 and 185 °C and three press duration of 3, 3.5 and 4 minutes. The mechanical and physical properties of the boards were measured and the results were statistically analyzed. The results indicated that press temperatures and press duration did not impose significant effect on MOR, but with increasing the press temperature and press duration, the MOE of the boards improved and the highest MOE was observed applying 185 °C press temperatures and 4 minutes press duration. The internal bonding (IB) of boards increased with increasing press duration, and the highest IB was related to boards produced with 3.5 and 4 minutes press duration. The press duration significantly influenced the thickness swelling after 2 and 24 hours immersion in water, and the lowest values were observed in boards produced applying 3.5 minutes press duration, as expected from the results of highest IB at same condition. Generally it can be expressed that corn stalk shows the potential as raw material to produce standard Medium Density Fiberboard.
Pulp and paper
Ahmad Jahan - Latibari; Fardad Golbabaei; Amir Zyadzadeh; Majid Farzi; Arad Vaziryan
Abstract
Fiber length, diameter and lumen diameter and its distribution is determined. Five stalks were randomly selected and after cleaning, the internodes and nodes of each stalk were separated. Each part was depithed manually and then experimental samples were cut from these depithed parts. ...
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Fiber length, diameter and lumen diameter and its distribution is determined. Five stalks were randomly selected and after cleaning, the internodes and nodes of each stalk were separated. Each part was depithed manually and then experimental samples were cut from these depithed parts. Each sample was defibered according to procedure developed by Franklin, 1954. After defibration, fiber length, diameter and lumen diameter of 30 fibers were measured. Each stalk contained 10 nodes and internodes.
Average fiber length of internodes and nodes were determined at 1.004 and 0.802 millimeter respectively. The difference in averages of fiber length for different stalks, different heights in each stalk and between nodes and internodes were significant at 99% level. Fiber length distribution curves for internodes, nodes and all fibers show uniform and symmetrical distribution and the highest points in distribution curves are all at similar fiber length.
Average fiber diameter for internodes and nodes were determined at 16.8 and 20.1 µm respectively which are significantly different at 99% level. Fiber diameter distribution curves for nodes, internodes and all fibers also shows uniform and symmetrical shape, but the highest point for internodes is located at lower fiber diameter than nodes. The average lumen diameter for internodes and nodes were measured at 9.42 and 12.7 respectively which is significantly different at 99% level. The distribution curves for lumen diameter is identical to fiber diameter.
The results indicate that the fiber geometry of cornstalks is similar to hardwoods and other agricultural residues and it can be utilized for production of lower grade pulps such as fluting paper pulp.
