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Man has a long history of using lignocellulosic materials for producing composites. Its beginning can be traced back to the ancient times when the Egyptians added straw to mud to make bricks, which proved to be very strong and durable. Today, bio-based composites are becoming attractive in both commercial and non-commercial appli- cations. Wood plastic composites (WPCs) are widely used throughout the world; the most common type of such panels is produced by mixing wood ?our and plastics. where can buy plastic outdoor benchThese composites are transformed by extrusion processes to obtain structural building applications including, pro- ?les, sheathings, decking, roof tiles, and window trims, with improved thermal and creep performance compared with un?lled plastics . In general, the stability of any building system consisting of interconnected components is directly related to the performance of the fastening ele- ments. Common wire nails and screws are widely used for making joints on WPCs particularly in decking, outdoor furniture, etc.
because of their good performance and low cost . Therefore, knowledge of the withdrawal strength of nails and screws for WPCs will provide useful infor- mation about the stability and durability of the materials in the building system . Although numerous studies have been carried out to evaluate the withdrawal strength of different types of fasteners (such as dowel, nail, and screw) embedded in wood species and wood-based panels , little information has been reported on the withdrawal strength of nail and screw in WPCs .Accelerated deforestation and forest degradation, in addition to a growing demand for wood-based products, have raised an important issue regarding the sustained supply of raw materials. the biggest wpc marketConsequently, there is need for alternative resources to substitute wood raw materials. Therefore, researchers, both in industry and academia, are looking for new sources of lignocellulosic materials. Among the possible alternatives, the develop- ment of composites using agricultural residues, non-wood plant ?bers, and fast-growing species could play a major role in providing the balance between supply and demand for the manufacturing of wood-based composites such as WPC.
Agricultural residues are excellent alternative waste materials to substitute wood because they are plen- tiful, widespread, and easily available. Aside from their abundance and renewability, utilization of agricultural residues has advantages for economy, environment, and technology .Iran has poor natural forest resources that cover only about 7 % of the country's land area. Similar to many developing Asian countries, deforestation and over-har- vesting in Iran have created environmental issues. pvc boards termite proofOn the other hand, increasing demand for forest resources in various applications has led to the shortages of wood supply. For these reasons, in the recent years, research in Iran and elsewhere has been focused on a wide range of alternative ?bers as supplements to, or as a direct substi- tutes for wood in the manufacture of wood-based products. Besides, the decision to utilize a new material in place of an established one should be taken with utmost care to ensure that all the characteristics of the new material are well understood.
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