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Wood is one of the most important raw materials in Brazil, mainly for the industry of construction, packing, furniture among others. In the mechanic process of cutting wood, large volumes of sawdust can eventually pollute the rivers and landfills. There is a great deal for the society to find some rational use for such wastes, like as an energy source to replace the coal, the diesel oil, and enhances its capability in exchange for carbon credits. Following this trend, studies were developed at several countries looking for the reuse of vegetable fibers as reinforcement in thermoplastics matrices, for several industry applications. The objective of this work was to develop a composite from Pinus sp residues and recycled plastics, such as polypropylene (PP) and polyethylene (PE), seeking their use in the manufacture of pallets components. Characterization of the residue of saw dust of the manufacturing process of pallets One wood pallets company, located at the region of Campinas, Brazil, leads daily amount of 100 ton of waste from sawdust. Currently this waste is used as a source of burning energy in industries of this region.
Pinus sp is the principal waste wood used as a load of more thermoplastics in Brazil. Its bulk density is between 0.15 a 0.374 kg/m3 . Its chemical composition is 50.1% of cellulose, 30.3% of lignin, 9.7% of hemicelluloses and 10% of other substances (CAMARGO, 2006). Sawdust as reinforcement in thermoplastic (wood-plastic compound) Thermoplastic composites with sawdust (WPC) have some advantages over the conventional mineral material. They are lighter in compared to the fiber glass Moreover, these materials are less abrasive and not wear the equipment . Consumption of composite is very significant in the USA - about 1,170,000 ton of wood-profile extruded plastic was produced. In Europe, consumption was approximately 1,200,000 ton each in 2007. The consumer sectors are furniture, packaging (pallets) and construction (manufacture of terraces, balconies, ceilings, etc.). In the other countries, like Brazil and Chile, consumption still comes up in the cultural barrier that can be broken through an appeal of environmental issues facing marketing . Thermoplastics modified by vegetable fibers are recent and its melting point should be below the point of degradation of the fibers, usually between 200 to 220 ��C . The polypropylene is a polymer of the same family of polyethylene and differentiated by this one by the presence of radical methyl (CH3) in monomeric unit. The position occupied by methyl radical determines the classification of polypropylene in atatic, sindiotatic, isotatic.
The configuration gives the polymer isotatic a greater mechanical strength (SANTOS, 1998). Use of waste of low density polyethylene (LDPE) recycled The low-density polyethylene is highly translucent. It is resistant to most chemicals product, except for strong acids, some ketones. Almost half polyethylene produced in recent years has been to the film or plastic film because of its low density, flexibility, high resilience, resistance to wear, resistant to moisture and chemicals .Particle size distribution was obtained according to the standard of Brazilian Standardization (ABNT NBR-7217), which defines the mineral particle size distribution, since there is no specifics standard for clusters on the plant origin. Initially, it was weighed 180 g of each dried residue, subjecting them to the screening process using a mechanical shaker of sieves for a period of approximately 5 minutes. A standard series of sieves ABNT was used, with openings of 4.76 mm and 2.38 mm, 1.19 mm and 0.59 mm, 0297 mm and 0149 mm and residue. After the screening, it was obtained the mass of the material retained at each sieve.
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