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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.

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.

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.