Iranian Journal of Wood and Paper Science Research
Year:2005 | Volume:20 | Issue:2 (23)|Papers Count:10

Poplar trees are classified as a fast growth trees and because of short rotation period, and suitable technical properties, are considered by pulp and paper making industries. In this study, physical and anatomical properties and pulp and paper of three colons of poplar trees, populous Alba. L. colon 44.9, populous deltoids 69.55, and populous euramerican are investigated. The average fiber length of these three colons were 0.854, 1.148, 1.08 mm. respectively and their average dry specific gravity were 0.386, 0461, and 0.341 g/cm3, and also their average cellulose content were 50.5, 51.5, and 49.5 percent.For Kraft process cooking of the mentioned colons, three cooking time, 1, 2, and 3 hours, 17°C cooking heat, 25% sulfidity, and active alkali at 3 levels, 15, 17.5, and 20% were used. The results show that p. alba, colon 44.9, and p. deltoids colon 69.55 with using 20% A.A and 3 hours cooking time have 53% yield and 18 kappa number.

The objective of this study was to investigate the effect variables on tensile load of dowel joints in particleboard fastening. T-shape samples were made. Variable factors included dowel type: smooth and rough, dowel diameter: 6,8 and 10 mm, degree of freedom of less than 0.25, 0.25, 0.5 and depth of penetration 2D, 3D and 4D. Combination of above variable factors revealed 54 treatments Considering four replication for each combination, a total of 216 samples were made and tensile load of joints were measured. Tensile load of rough dowel joints with 10mm dowel diameter, 4D depth of penetration and 0.5mm degree of freedom was superior. The measured load at this combination of variable was 1.76 KN.

Anatomical, chemical and pulping characteristics of Cotton stalk as a nonwood material.Fiber length, fiber diameter, lemun and cell wall thickness were measured at 24.47, 16.43 and 4.02 mn respectively. Paper making coefficients were also calculated coefficient, flexibility coefficient and ranckl coefficient were calculated at 34.28, 67.14 and 48.93 respectively.Chemical composition of cotton stalk was determined at 47.83%cellulose, 21.66% lignin, 2.13% alcohol-acetone extractives and 2.83% ash.Soda pulping at following variables was investigated. Three levels, of cooking temperature (140, 160 and 180 degree Celsius), three cooking time (30, 40 and 50 minutes) and raw material condition (normal and debarked stalks). Active alkali of 20% (based on NaOH) and liquor to wood ratio of 5: 1 were kept constant for all soda cooks. The optimum combination of variables160 degree Celsius I temperature, 40 minutes time and debarked raw material. The yield and kappa no. of pulp obtained at this cooking condition was 50.4% and 89.15 respectively.

The natural forests and rangelands of Iran are reach in their insect fauna. The survey caring out in many province of Iran during 1993-2005 and the long horn beetles (Cerambycidae) were collected from these areas. In this regard different setting of ecosystems such as forests, urban vicinities, poplar plantations, poplar research stations, fruit garden, lumberyards in many part of Iran had been visited and the beetles Were captured directly by hand, light trap, sweeping net, chopping the infested logs of host trees.The collected specimens were identified and geographic distribution and economic importance of them were studied. Theretofore, about 80 specimens were identified and sixteen of them are the pest of different trees and they have economic importance. These specimens belong to four subfamilies namely Prioninae, Lamiinae, Cerambycinae and Parandrinae as follow: Prioninae (Megopis scabricernis Scopolu Prionus coriarius L.), Lamiinae (Saperda spp. L. Oberea oculata L., Morimus verecundus Faldermann, Monochamus sutor (L.), Cerambycinae (Osphranteria coerulescens Red, Cerambyx cerdo L., Xehopachys matthiesseni Reitt., Aeolesthes Sarta Solsky, Aromia moschata L., seudophilus testacyeus Gah., Derolus mauritanicus iranensis Gahan. Stromatium Fulvum Villers., Hylotrupes bajulus L.), Parandrinae (Parandra caspica Men).

In this study, in order to gain the best Particleboard made of production, the effect of three factors, resin content, hardener content, and press time on the static bending strength, Internal board, water absorption, and thickness swelling after 2, and 24 hrs. Immersion in water of boards mades are studied. 54 boards were made and after measuring of their physical and mechanical, the results was analyzed with using the factorial completely randomize design.The results show that increasing resin content causes better quality of properties of boards such as bending strength, Internal bound, and dimensional stability.Increasing of press time from 5 to 5.5 min. Causes better bending strength, Internal board and dimensional stability of boards where, with increasing of press time from 5.5 to 6 min are observed that all of the mechanical properties of boards were reduced.Totally speaking, it can be noted that changing of bending properties, internal bound, water absorption, and thickness swelling after 2, and 24 hrs. Immersion in water of boards made show that optimum condition are 11% resin, 2% hardener, and 5.5 min press time for making particle board made of Bagasse. 

Wood -Plastic panels were made from high density polyethylene (as resin) and MDF waste and particleboard waste (as natural fiber) at 60, 70 and 80% by weight fiber loading. Density and dimensions of the panels were 1g/cm3 and 35*35*1 cm, respectively. Physical properties of the panels including equilibrium moisture content, long term water uptake and thickness swelling behavior were studied.Results indicated that equilibrium moisture content, maximum water uptake and thickness swelling of wood plastic samples increased with the increase in fiber content from 60% to 80%. Moreover, samples with higher fiber content faster reach to saturation point.

The possibility of producing wood-plastic panels using melt blend method was studied in this research and mechanical properties of the panels including flexural modulus, flexural strength, screw and nail withdrawal resistance, and impact strength were studied.Wood -Plastic panels were made from high density polyethylene (as resin) and MDF waste and particleboard waste (as natural fiber) at 60, 70 and 80% by weight fiber loading. Density and dimensions of the panels were 1g/cm3 and 35*35*1 cm, respectively. Results indicated that the mechanical properties of the composites are strongly affected by the proportion of the wood flour and polymer in the material. Maximum values of flexural modulus of wood plastic panels were found at 70% fiber content in both methods. Flexural strength, screw and nail withdrawal resistance and impact strength of wood plastic composites reduced with the increase in fiber content from 60% to 80%.

Density profile of three types of medium density fiberboard (MDF) panels used in Iran market was studied through direct method and gradually removing of layer. Modulus of elasticity, bending strength, internal bond, water absorption and thickness swelling were also determined. The results show that the shape of density profiles in all types of panels is nearly symmetric and normal, but the profil density in one was deeper, so it showed higher modulus elasticity and bending strength. No significant difference in internal bond was observed between different types of panels.