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The effect of using nanoclay on MDF properties was investigated. Sodium montmorolonit (NA+MMT) was used in three levels of 0, 3 and 6 percent based on dry weight of two resins of urea formaldehyde (UF) and Methylene diphenyl diisocyanate (MDI). Modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding (IB), thickness swelling (TS) and water absorption (WA) of MDF were measured based on EN standard. Results demonstrated that with the increase of nanoclay in both UF and MDI resins MOR and MOE of MDF increased significantly in such a way that with the use of UF containing 6% nanoclay MOR increased by 33%. Although, IB was significantly affected by UF containing nanoclay, MDI containig nanoclay caused reduction in IB. WA and TS of MDF made from MDI did not show significant variation by increase of nanoclay but those made from UF resin positively affected by adding nanoclay in such a way that MDF made from 3% nanoclay showed 41% loss in TS compared to those made from pure UF.

The purpose of this study was to investigate which equation (Linear, Exponential equation and quadratic) can describe exactly the interaction effect of particle size and adhesive percent and predict mechanical properties of particleboard (modulus of rupture, modulus of elasticity and bending strength). For this work three levels of density including 0.65, 0.7, and 0.75 g/cm3 and also, three levels of adhesive content including 8, 9.5, and 11% and four levels of slenderness ratio of particles including 46.35, 33.7, 21.51 and 12.87 were used. After conducting the experiment and preparing the data, three kind of equation (linear, quadratic and Exponential equation) for each mechanical property based on slenderness of particles, density and adhesive percent obtained. The result indicated there was no correlation between mechanical properties of particleboard and quadratic equation but there were good correlations between linear and Exponential equation. Also the result indicated that Exponential equation can describe efficiently the simultaneous effect of slenderness and adhesive present on the mechanical properties of particleboard, and it can predict better mechanical properties than linear equation.

Poplar lumbers with nominal thickness of 5 cm from Taleghan region, located in west of Karaj were dried under three different schedules including T8-F4 (recommended schedule by F.P.L for poplar), T8-F5 and T9-F4. The purpose of this research was to study the effects of the kiln’s rows (upper, middle, lower) on the quality of the dried boards. Dry bulb temperatures for the schedules were adjusted at 54, 54 and 60 °C, while the final temperatures were adjusted at 82, 82 and 71 °C, respectively. The severity of warping, internal checking and surface checking in kiln dried lumbers were measured and analyzed. The results indicated that the boards in upper, middle and lower rows of the kiln, in all three schedules, did not have any significant difference in 95% confidence interval. Also, the final moisture content of the boards in all three rows and all three schedules were in acceptable quality.

In this investigation the effect of using of UF and MUF Resins on Physical and mechanical Properties of Particleboards Produced from Rice Straw and Aspen Particles has been studied. The aim of this study was to determine of physical and mechanical properties of rice straw– particleboard. Single-layer particleboard was produced. That was produced with 11% MUF and 11% UF. For using of UF and MUF 2% hardener was added to adhesives. The Press condition for MUF was: 1750C for 4 minutes and also for UF application was 1750C for 6 minutes. Another variable factor was the rice straw content in three levels (15%, 30% and 45%). Other factors such as board density (0/7gr/cm3), mat moisture (12%) were constant factors. The results indicate that increasing rice straw to wood particles cause some reduction in modulus of rupture , and internal bonding , and some increase in thickness swelling , and water absorption of manufactured boards. But comparing and grouping means by Duncan test showed that in the most case these effects were insignificant when rice straw add to wood particle up to 30%. Particleboard bonded with 11% MUF had the highest bending strength. Particleboards bonded with MUF had better bending strength, shear strength, thickness swelling and water absorption after 2, 24 hours immersion. Grouping the experimental data while using Duncan method was indicated of the fact that an optimum condition for manufacturing particleboard while using a mixture of rice straw and wood particles is to add 30% rice straw to the mixture , use 11% melamine urea formaldehyde resin and employ a pressing time of 4 minutes.

Neutral sulfite semi chemical pulping of Canola residues has been investigated. Canola residues collected from research farm at Agriculture and Natural Resources, University of Tehran, in Karaj. Chemical composition of Canola residues including cellulose, lignin, extractives soluble in ethanol-acetone and ash were determined using relevant TAPPI standard test methods. Fiber dimensions of Canola residues were also measured. Then neutral sulfite semi chemical pulps were produced from Canola residues applying following conditions: Cooking time at 3 levels(20,40,60min),chemical charge at 5 levels(8,10,12,14,16 %), Cooking temperature was kept constant for all cooks at 175ċ , Na2SO3 to Na2CO3 ratio was 3:1,and liquor to Canola residues at 8:1. Each pulping was repeated tree times. At the end of each cooking, initial defibration was carried out using a laboratory disc refiner. Total yield before defibration and yield after defibration and screened yield were determined. The highest yield (72%) was obtained at treatment combination of and the lowest yield (58.7%) was in treatment of .Both factors, time and chemical charge, had significant effect on yield and increasing these two factors caused lower yield.

In order to investigate the effect of compatibilizer, (MAPP), on physical and mechanical properties of reed stem flour- polypropylene composites, 60 mesh size reed stem flour particles were compounded at 60% and 70% by weight with a polypropylene homopolymer with a melt flow index of 18 g/10min. Two compounds were prepared from which formulations with 60 mesh particle size and 60% and 70% filler loading were selected to evaluate the role of the compatibilizer. One of them was without MAPP and the other one had 3% MAPP by weight. Totally, 4 compounds were prepared. Composites were produced using a twin screw counter rotating extruder. Then, mechanical tests including static flexural test, tensile test, Izod impact test and hardness test were carried out. Physical tests including water absorption and thickness swelling were also performed. All testing was in accordance with ASTM D7031-04 specification. The results of physical tests have indicated that by the increase in reed flour content, maximum water absorption and maximum thickness swelling increased. Generally, by adding the coupling agent (MAPP), the physical and mechanical properties significantly improved.

In this investigation, the effect of paraffin content and press time and temperature on practical properties especially surface roughness of particleboard is studied. The variables such as paraffin content at 0, 1& 2 percent, press temperature at 170° and 180° C and press time of 4 and 5 minutes were investigated. Modulus of rupture, modulus of elasticity, shear strength, water absorption and thickness swelling after 2& 24 hours soaking in water & surface roughness were measured. The results indicate that there is no significant difference on the influence of paraffin content on either MOR & MOE of the particleboard. But increasing paraffin content decreased shear strength of panels. However, addition of paraffin reduced water absorption and thickness swelling. Press temperature had no significant influence on measured properties, but this variables increased surface roughness. Increasing press time, improved MOE, but showed no significant influence on other properties.

Apparent Density of paper is the most effective physical property which directly and indirectly affects most of the strength and optical properties of paper such as tensile strength, modulus of elasticity, light scattering coefficient as well as the bonded area between fibers. Since paper making variables influences the apparent density of paper, in this study, the influence of OCC pulp freeness, and drying conditions are investigated. The influence of three freeness levels of 350,450, and 550 CSF, drying under strain and unstrained, drying temperatures of 100, 150, 200 C and drying pressure of 7 and 10 kg/cm2 are studied. The relationship between paper making variables and apparent density is developed. All measurements of apparent density were analyzed using Minitab 15 and regression model between independent variables was calculated. The results showed that both pulp freeness and drying temperature had the highest impact on apparent density and both factors increased the apparent density. The response of apparent density of the hand sheets dried at 200 ◦C varied considerably and was analyzed thoroughly. Higher pressure increased apparent density of the sheets. The combined effect of variables is also considered. The combined effect of pulp freeness and drying temperature caused lignin softening and delamination. However, the influence of increasing the drying pressure for unrefined and less refined pulp is not significant. Furthermore, for unstrained drying, the influence of freeness on apparent density was more than strained drying. Manufacturing of more desirable quality papers would be possible considering the obtained results and the effect of Apparent Density on paper strength properties.