Zinat Farhadi; Ahmad reza Saraeian; Mohammad reza Dehghani firuzabadi
Abstract
This study was done to investigate the effect of bark content on the physical and mechanical properties of kraft pulp from chips Ppopulous deltoids. Three tree of the populous deltoids from the same age were randomly selected cut from Shastkalate research forest Gorgan. A disc was taken from each tree. ...
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This study was done to investigate the effect of bark content on the physical and mechanical properties of kraft pulp from chips Ppopulous deltoids. Three tree of the populous deltoids from the same age were randomly selected cut from Shastkalate research forest Gorgan. A disc was taken from each tree. The discs were completely debarked and wet weight of wood and bark from each disc was determined. Then weight ratio of wood/bark was determined in each disc. Kraft pulp was prepared under following pulping condition: sulfidity 25%, AA: 20%, temp: 170 0c, l/w: 6/1 and bark content as 0 , 6, 12, 18 and 24%, by weight. Pulp with kappa number around 20 was prepared from each treatment, which were separately beaten to reach freeness value around 350 ml,CSF. To determined the effect bark content on yield and kappa number of the pulp and their physical and mechanical properties, F test was used in completely randomized, and for comparison of the means, Dunkan test was used. Yield and kappa number of the pulps were as 50/32 - 52/03% and 20/37 - 21/17, respectively. With increasing, of the bark content, density of paper was decreased and the lowest value of which was 0/477 g/cm2for bark – contained pulp. Also, with increasing of the bark content to 18%, strength properties of the related pulp was improved.
Ali Pesaraklu; Mohammadreza Dehghani firoz abadi; Abolfazl Karegarfard; Taghi Tabarsa
Abstract
The objective of this study was to manufacture water resistant kenaf stalk particleboard.Twenty seven boards were produced using 170 °C steam treated kenaf particles, 30 and 60minute treatment time and three resin types include urea-formaldehyde, melamineformaldehydeand a mixture of fifty percent ...
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The objective of this study was to manufacture water resistant kenaf stalk particleboard.Twenty seven boards were produced using 170 °C steam treated kenaf particles, 30 and 60minute treatment time and three resin types include urea-formaldehyde, melamineformaldehydeand a mixture of fifty percent each. Physical and mechanical properties weremeasured and the results analyzed in a complete random design plan and by the factorialanalysis. The results showed that boards made from treated particles with 60 minute treatmenttime and Urea Formaldehyde resin had the highest bending strength. Modulus of elasticity(MOE) improved with an increase in treatment time. The greatest MOE was achieved with theboards produced using urea-formaldehyde and the greatest MOE was achieved with the boardsbonded with urea-melamine-formaldehyde resin. Moreover, with increasing treatment time from30 to 60 minutes internal bond strength (IB) reduced. Thickness swelling and water absorptionof the boards was significantly improved with increasing treatment time.
ّFahimeh Shabanalizadeh; Mohammad reza Dehghani firoz abadi; Abolfazl Karegarfard; Mehrab Madhoshi
Abstract
Utilization of kenaf core and stalk for the production of medium density fiberboard was investigated. Control boards were produced using poplar wood fibers and compared with kenaf boards. Urea formaldehyde resin was used. Medium density fiberboards were made at two densities of 0.55 and 0.75 g/cm3. ...
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Utilization of kenaf core and stalk for the production of medium density fiberboard was investigated. Control boards were produced using poplar wood fibers and compared with kenaf boards. Urea formaldehyde resin was used. Medium density fiberboards were made at two densities of 0.55 and 0.75 g/cm3. Six combinations of variable were tested and for each combination of variables, 3 replications and the total of 18 laboratory MDF boards were produced. The kenaf core and stalk fiber dimensions and the mechanical and physical properties of the MDF boards were measured. Factorial experimental design was used for statistical analysis of generated data. Results showed that average length of kenaf core and stalk fiber are 3.607 and 0.78 mm, and their respective diameters are 41.48 and 36.76 μm. The results of modulus of rupture, modulus of elasticity, internal bonding and thickness swelling after 2 and 24 hours immersion in water showed that kenaf core fiberboard with the density of 0.75 g/cm3 are above the required values for these boards which indicate that these properties are comparable with MDF from wood. It can be expressed that kenaf core fibers can substitute the poplar wood fiber for MDF production. The modulus of rupture, modulus of elasticity and internal bonding of MDF boards produced using kenaf core was improved as the density of the boards increased. The thickness swelling after 2 and 24 hours immersion in water was comparable to poplar fiberboard. Kenaf stalk fiberboard showed lower mechanical and physical properties due to the presence of bark fibers.
