Hemicellulose of Southern Yellow Pine wood spices was extracted by pressurized hot water at three different temperatures: 140oC, 155oC and 170°C. Compounding with PP (polypropylene) was per-formed by extrusion after preparing wood flour and sieving to determine its mesh size. The ratio of wood to polymer was 50:50 based on oven-dry weight of wood flour. All extraction treatments and control samples were compounded under two sets of conditions, without and with 2% MAPP as coupling agent. Injection molding was used to make tensile test samples (dogbone) from the pellets made by extrusion. Thermal properties of WOOD-PLASTIC COMPOSITES were studied by TGA and DSC while the thermal stability of pretreated wood flours, PP and MAPP were studied by TGA as well.The greater weight loss of wood materials was an indication that higher treatment temperature increases the extractability of hemicellulose. The removal of hemicellulose by extraction improves thermal stability of wood flour, especially for extraction at 170oC. WOOD-PLASTIC COMPOSITES made from extracted fibers at 170oC showed the highest thermal stability. Coupling agent did not have a significant effect on thermal stability but it improved the degree of crystallinity of the COMPOSITES.Surface roughness of wood fiber increased after treatment. Extraction of hemicellulose increased the degree of crystallinity but it was not significant except for samples from treated wood flour at 170oC and witli MAPP.

In this study, the possibility of making a composite from bagasse was investigated. Bagasse-polypropylene fiber samples with different bagasse percentages (15, 25, and 35%) and coupling agent (0, 1.5, and 3%) were made, and their mechanical properties were examined. The results showed that with an increase in bagasse fibers, the flexural strength and tensile modulus did not change significantly, but the modulus of elasticity and energy at the breaking point decreased significantly, but the tensile strength increased. The results of the impact resistance test showed that although the impact resistance decreased and increased slightly with an increase in the percentage of bagasse fibers and coupling agent, this amount of decrease and increase was very small and insignificant, and the results of this test were random and unrelated to the increase in raw materials. However, in the impact resistance test without a notch, a significant difference in the decrease in impact resistance was observed with an increase in fibers and its increase with an increase in coupling agent. Overall, all measured engineering properties in this study improved, except for impact resistance, which decreased with an increase in fibers. It is suggested that to improve the engineering properties of this type of composite, the bagasse percentage and coupling agent should be increased up to 30% and 3%, respectively.

Influence of the acetylation and the compatibilizer MAPP on the long term swelling rate of polypropylene/ acetylated wood fiber COMPOSITES (WPCs) was the main concern of the current research. Wood fibers were reacted with acetic anhydride without a catalyst to achieve weight percent gains (WPGs) of 4.5, 7.5 and 17.68%. The acetylated fibers were mixed with MAPP (0 and 2%) as well as the polypropylene as the matrix polymer and molded at 180oC in a hot press. Test specimens were cut from the samples and soaked in water for 1512 hours at room temperature to determine the thickness swelling as well as the rate of the swelling in the WPCs. Results revealed that the thickness swelling of the acetylated COMPOSITES was significantly reduced in comparison with the non-acetylated one. Application of the MAPP decreased the swelling as well. However, there were no significant differences between the acetylated WPCs containing the compatibilizer with the COMPOSITES without MAPP. The Shi and Gardner (2006) model was adopted to evaluate swelling in the acetylated COMPOSITES.

In this study, the possibility of producing WOOD-PLASTIC panels was studied using two different blending methods including melt blend and dry blend. WOOD-PLASTIC panels were made from recycled high density polyethylene (as resin) and MDF waste (as natural fiber) at 60, 70 and 80% by weight filler loading. Nominal density and dimensions of the panels were 1g/cm3 and 35×35×1 cm, respectively. The mechanical properties of the panels including flexural elastic modulus, flexural strength, screw and nail withdrawal resistance, and impact strength were studied. 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%. Mechanical properties of samples made with dry blend method were generally higher than those of samples made with melt blend method for all corresponding formulations.

The main objective of this study was to examine, the use of thermo set epoxy resin and wood powder for making wood polymer COMPOSITES. Results showed that mechanical properties of wood polymer COMPOSITES that are manufactured were better than wood specimen. Also the water uptake of samples was measured and the results showed the water absorption of wood polymer composite is too much less than wood sample. Images and infrared spectroscopy analysis support this fact that wood polymer COMPOSITES are more stable than wood. Then the effects of adding wood powder to fiberglass COMPOSITES were examined. The Results have clearly shown that adding appropriate amount of wood powder to fiber COMPOSITES will considerably improve their physical and mechanical properties.

As the outdoor application of Wood PLASTIC COMPOSITES (WPCs) become more widespread, the resistance of these products against weathering, particularly ultraviolet (UV) light becomes more important. When WPCs are exposed to outdoor ultraviolet light, rain, snow and atmosphere pollution, they will be degraded which can be indicated by color fade. To investigate the effects of methylation and Anti-Oxidant separately and together on discoloration of weathered wood PLASTIC COMPOSITES, COMPOSITES of poplar wood flour and high density polyethylene.Were made according to the ASTMD 2565, samples were placed in Atlas Xenon apparatus for 250 and 2000 hours. Discoloration and FT-IR spectra of the samples were measured and compared.The results have shown that methylation in short term and long term can relatively reduce the discoloration of weathered samples and also in short term can hinder the photodegradation. FT-IR spectra showed that, in long term, neither of the treatments could protect lignin from irradiation within wood flour. But methylation limited the depth of penetration of weathering. The Antioxidant did not have an influence on color change in a long period of time, but was able to relatively decrease it in short term.

In this study, feasibility of foaming wood PLASTIC COMPOSITES using injection molding process was investigated. The effect of lignocellulosic raw material (Poplar saw dust and soybean straw flour) on the properties of COMPOSITES was examined. Wood PLASTIC composite boards with 3.2 mm thickness, 105 mm width and 105 mm length were prepared using high density polyethylene granules. The foaming agent (Azodicarbonamide) at 2 wt % was also used. The scanning electron microscope micrographs confirmed that foaming process has been successfully carried out. The Results showed that all mechanical properties (except the impact strength) decreased while water absorption increased as the microcellular foaming method was used. Adding soybean straw flour to the foam structure led to the decrease in flexural strength, flexural modulus of elasticity and tensile strength. Water absorption and thickness swelling were negatively affected with the addition of soybean straw flour.

In this research, the mechanical behavior of COMPOSITES made with polyethylene matrix and wood powder reinforcement have been investigated. In order to improve the mechanical properties, the wood powder has been added to polyethylene at three levels of 30, 40 and 50 wt. %. The material was mixed using an internal mixer Haake and then the material was removed from the mixer and was granulated by a crushing machine. Finally, the granules were molded using an injection molding machine and tensile test specimens were made according to ASTM D638 standard and bending test specimens were made according to ASTM D790 standard. After preparing the specimens, a tensile and flexural test performed on them. The results of the mechanical tests show that the amount of elastic modulus increased with increasing the amount of wood powder so that the highest amount of elastic modulus was observed in the specimens containing 50 wt. % wood powder. Also, the highest strength in the tensile test was observed at the level of 30 wt. % of the wood weight and the highest flexural strength was in the 50% level of wood weight. Also, mechanical tests were simulated using Abaqus software.