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In this study, the effect of walnut shell and charcoal flour on the applied characteristics of the resulting plastic composites was investigated. For this purpose, walnut shell and charcoal flour in three levels of 20, 30 and 40% were mixed with high density polyethylene using Brabender internal mixer during the melt mixing process, then standard test samples were made by injection molding method. Mechanical properties including tensile and flexural strength, tensile and flexural modulus and impact strength were measured. Physical properties including water absorption and thickness swelling after 24 hours immersion were evaluated and scanning electron microscopy images were also examined. The results showed that the flexural strength and impact strength of the wood plastic composite containing 40% walnut shell flour were higher than the samples containing 40% charcoal flour. Also, by increasing the walnut shell and charcoal flour from 20 to 30%, the flexural strength increased by 3.3% and 6.1%, respectively, and by increasing the walnut shell and charcoal flour from 20 to 40%, the flexural modulus increased by 51.9% and 63.8%, respectively. Other results of mechanical strength indicate that with increasing walnut shell charcoal from 20 to 40%, tensile strength and modulus increased to 22.9 and 109.7%, respectively, and with increasing walnut shell and charcoal flour from 20 to 40%, the impact strength decreased by 6.6 and 5.4%, respectively. The results of physical properties showed that with increasing walnut shell and charcoal flour from 20 to 40%, water absorption for 24 hours decreased by 19.2 and 8.4%, respectively, and thickness swelling by 24 hours decreased by 53.6 and 46.7%, respectively. [ABSTRACT FROM AUTHOR]

This research aimed to investigate the effect of chemical treatment of wood flour on some of physical, mechanical and morphological properties of wood plastic composite. Chemical treatment of wood flour at 7 levels without treatment, acetylation, benzoylation, mercerization, magnesium hydroxide, calcium hydroxide and warm water treatment were considered as variable factors. For evaluate reaction of wood flour with chemical materials, weight percent gain (WPG) were calculated. After chemical treatment, Wood flour and polypropylene with weight ratio of 60 to 40 and 4 per hundred compound (phc) of coupling agent mixed in the extruder device and then the specimens were fabricated by injection molding method. Then mechanical tests Included tensile, flexural and impact strength and physical examination, including water absorption and thickness swelling was performed on specimens according to (ASTM) standard. Also to study the morphology of the composites, scanning electron microscopy (SEM) was used. The results showed that by chemical treatment the mechanical strength increased and physical properties such as water absorption and thickness swelling decreased. Also the highest chemical treatments of wood flour was related to the banzylation treatment. As well as obtained results of scanning electron microscopy was indicate improve in cross linking between fibers and polymeric matrix on effect of chemical treatment, so that in treatment samples exiting of fibers into the matrix not observed.

In this study, effect of nano-wollastonite on fire resistance characteristics of wood flour/polypropylene composite was investigated. The composites samples were manufactured using a dry blend/hot press method. In this study, the dried wood flour of beech as the filler in a 60%, poly propylene as the matrix in a 37% and polyethylene grafted with maleic anhydride as the coupling agent in a 3% total weight was used. Also, nano-wollastonite was used in four levels of dried wood flour loading (0, 1, 3 and 5%). Nominal density and dimensions of the composites were 1 g/cm3 and 1*20*25 cm, respectively.Bending strenght according to ASTM standard and Fire resistance characteristics such as, flammability duration, duration of flame after removing the burner, duration of glow after removing the burner and mass reduction were measured acceding to ISO 11925. Results indicated that by increasing the nano-wollastonite increases the bending strengh,MOE and flammability duration increased but mass reduction, duration of flame and duration of glow decreased. Also the dispersion of nano-wollastonite in composites was evaluated by Filed Emission Scanning Electron Microscopy (FE-SEM).

In this study, the effect of nanoclay particles and coupling agent on the physical and mechanical properties of polypropylene / waste paper composites was studied. To meet this objectives, waste paper fibers with polypropylene in 50% by weight, nanoclay (0, 2 and 4%) and coupling agent (0 and 3%) were compounded in an internal mixer at 155°C and 60rmp and the samples were prepared by injection molding. The results showed that the physical and mechanical strength of composite improved in the presence of coupling agent. As well as water absorption, thickness swelling, flexural and tensile strength and flexural and tensile modulus, were improved by increasing of nanoclay particles content, however notched impact strength was reduced. Also, study on structural behavior of composite with x-ray diffraction showed that nanoclay distributed as intercalation structure in polymer matrix, and distance between layers were increased with increasing of nanoclay particles content.

This study was conducted to investigate the feasibility of using waste textile fibers and the effect of nanoclay content on the physical and mechanical properties of a composite made from wood flour and polypropylene. Therefore, wood flour and polypropylene with a weight ratio of 50 to 50 with the textile waste fibers in two levels (0 and 15%), nanoclay in three levels (0, 2 and 4%) and 3% compatibilizer were mixed in an extruder at temperature of 160°C. Afterwards, the specimens were made with injection molding thechnology. Mechanical properties including tensile and flexural strength, impact strength and physical properties such as water absorption and thickness swelling were measured. The overall results showed that addition of textile fibers significantly improves the mechanical and and weakens the physical properties of the studied composite. The results indicated that the physical and mechanical properties of wood plastic composites except impact resistance, improved with increasing nanoclay content. The results of morphological studies to study the distribution of nanoclay using a range of X-ray diffraction (XRD) showed that the distribution of particles in the polymer matrix is the type of intercalation and by increasing the amount of nanoclay particles, layer to layer distance was increased.

This study was carried out to investigate the effect of weathering time on the physical and mechanical properties and color change in composite made of wood flour and high density polyethylene (HDPE). For this purpose, wood flour and polyethylene at a weight ratio of 60:40 with coupling agent were compounded in an internal mixer, and the samples were made in injection molding. Then, the weathering process by ultraviolet irradiation and water spray was done on the samples at different times of 250, 500, 1000 and 2000 hours in accelerated weathering apparatus. Finally, the physical and mechanical properties and color measurement of samples were tested, and compared with control samples. Results indicated that the flexural strength, flexural modulus, tensile strength and tensile modulus decreased with an increase in weathering time; however, the water absorption increased. Also, the yellowness of wood plastic samples decreased with an increase in weathering time and due to the lightness and color change increased.

In this study, the possibility of using canola tree stem residues and nanoclay particles on physical, mechanical and morphological properties of canola wood flour – polypropylene composites was investigated. The weight ratio of canola wood flour and polypropylene in the mixture was 50% and 50%and 0, 3 and 5 percent nanoclay and 4% MAPP were used. First, the ingredients were mixed using the extruder and then final panels were produced by hot pressing the compoud. Physical and mechanical properties were measured. Results indicated that water absorption and thickness swelling of the composites decreased as the nanoclay content was increased. The screw and nail withdrawal strength of wood plastic composite increased with increasing nanoclay up to 3% percent, then decreases with the increasing nanoclay to 5%. Morphologies of the nanocomposites were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the results showed increased d-spacing of clay layers indicating enhanced compatibility between polypropylene and nanoclay and canola stalk flour.

The objective of this study was to investigate the influence of coupling agent and the content of fiber on tensile strength and physical properties of wood/plastic composite produced from recycled polypropylene using mat forming procedure. Recycled polypropylene and three levels of Cotton Fiber Stem (50, 55 and 60%) and three levels of MAPP (0, 3 and 5%) were used. The results of tensile strength and physical properties were statistically analyzed using factorial experimental design. The results indicated that the tensile strength of composites with increasing MAPP content and decreasing of fiber content was improved However the modulus of tensile reduced significantly when the fibers content reduced. Also, the physical properties of composites were improved with increasing of MAPP consumption. Thickness swelling of composites after 24 hours and water absorption after 2 hours in boiling water showed these properties are lower when 50% fibers is used.

Wood plastic composites (WPCs) are produced from a mixture of wood (in different sizes) and resin (thermoset or thermoplastic). This product has many applications as structural and non-structural materials and since its emerge in market its use received an increasing trend. Adding wood flour to polymer not only improves its mechanical properties compared to net polymer, but also leads to products with moldability characteristics. With increasing demand of WPCs and reduction in forest harvest according to new protecting law of forestry, and lack of raw materials for producers, other lignocelluloses materials replace wood flour. Agricultural by-products such as hemp, coir, rice husk and bagasse (residual from sugar cane extraction) are the examples that can be used in WPCs. As the outdoor application of Wood Plastic Composites (WPCs) becomes more widespread, the resistance of its products against weathering, particularly ultraviolet (UV) light becomes more concerned. When WPCs are exposed to outdoor, ultraviolet (UV) light, rain, snow and atmospheric pollution, they will be degraded which is marked by color fade and loss in mechanical properties. Nowadays many manufactures of WPCs use bagasse as a raw material. Their production in different color and shapes are used as arbors and pergolas and also as decorative applications for outdoor uses. However, so far there has been no research done on the effects of weathering on composites made from bagasse. In present study, composites from bagasse and high density polyethylene, with and without pigments in master batch, have been made through extrusion. Then samples were exposed to accelerated weathering for 1440h. After this period of time samples were removed and their chemical, mechanical and surface qualities were studied. The results have shown that using bagasse as filler can relatively reduce the discoloration of weathered samples. Moreover, adding pigments to WPCs can increase colorstability, while it would cause higher loss in mechanical properties.

Coupling agents in wood fiber reinforced plastic composites play an important role inimproving compatibility and adhesion between polar wood fiber and non-polar polymermatrices by forming bridges of chemical bonds between the fiber and the matrix. Maleatedpolyethylene (MAPE) and diisocyanate (HMDI) are two most common coupling agents whichare subject to evaluation, singly and in mixture. Polypropylene and wood fibers werecompounded with Maleated polyethylene (MAPE) and diisocyanate (HMDI) in concentration of2% and 4% in solitary form and mixture form (HMDI %2 + MAPE %2) into pellets using acounter-rotating twin-screw extruder and mechanical test specimens were prepared by injectionmolding. The result showed that adding 4% MAPE and 2% HMDI individually lead to increasein flexural and tensile strength of the composites. Also adding (%2HMDI + %2MAPE) causedan increase of flexural, tensile and in particular the impact strength.

In this study, the effects of penetration depth and the installing method of screw (with drill and without drill) on withdrawal resistance in face and edge of wood plastic panel were investigated. To meet this objective, the wood plastic panels from the malach choob factory with density of 1.017gr/cm3 and 100×100×1.4 cm3 indimension were prepared, and for withdrawal resistance test the screw with 3 mm in diameter and 2.5 mm in length were used. Then, the samples with dimension of 2×6×1.6 cm3 according to Iranian national standard (No: 7416) were selected and the screw joint in face and edge of panels according to variables including penetration depth of screw (6, 9 and 12 mm) and penetration type of screw (with drill and without drill) was done and the withdrawal resistance were measured on the samples. The results indicated that the withdrawal resistance of screw in wood plastic panels increases with increase of penetration depth of screw from 6 to 12 mm. Also, because of fibre compression and high density, the face of panels had higher withdrawal resistance of screw as compared with edge of them. With drilling the withdrawal resistance of screw in wood plastic panels were increased.

To investigate the effect of acetylation and antioxidant separately and together on discoloration and contact angle wood plastic composite due to weathering , composite s were made using popular wood flour and high density polyethylene . the sample were exposed to natural weathering for 6 months. The results have shown that acetylation can relatively reduce the discoloration of weathered sample treatment than control sample.the antioxidant does not have any influence on color change but it seems that antioxidant could prevent partly destruction of plastic . It should be mention acetylating increased the surface contact angle befor weathering. But it could not protect the sample surface after the exposure period. So that was zero after weathering.

By utilizing three different grades of Polypropylene (PP) as matrix, two different kind of MAPP as coupling agent and without MAPP and Pistachio's flour, composite samples were produced. Physical and mechanical properties of wood plastic composites including: MOR, MOE, tensile strength, bending strength, impact strength, hardness, water absorption and thickness swelling (816 hours) were determined. Results indicated that the effect of different grade of polypropylene and coupling agent on water absorption, thickness swelling, hardness and impact strength variables were insignificant. Use of Polypropylene having higher Melt Flow Index (MFI) leads to increase in mechanical properties of wood plastic composite samples such as Bending and Tensile strength even if coupling agent wasn't used. Use of different kind of MAPP as coupling age in making wood plastic composites can result in better mechanical properties which based on their type have different effect.