CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Composite is the combination of a matrix and a reinforcement, which when combined gives properties superior to those of the individual components (Ashori & Nourbakhsh 2009a). Wood plastic composite (WPC) is therefore a combination of wood and plastic with the plastic as the matrix and the wood as the reinforcement. Wood plastic composite, (WPC), can be made from virgin materials as well as recycled ones. In Nigeria, plastic waste is enormous and its disposal has always been a challenge. In using recycled plastic of WPC, the advantages are that; raw materials are readily available, control the plastic waste menace and also save some virgin and natural products. Substantial increase in human population and the consequential strain on natural resources such as forests and the associated harmful results as well as the plastic menace challenging the nation are some of the challenges that make the study of WPC important. The green mentality and the shift in attitude are favouring environmentally-friendly products such as WPC (Azadeh et al., 2011). WPCs can be used in several applications such as profiles, sheathing, Decking, Roof tiles, Window trim, automotive parts, stepping stones etc. Natural fibers such as wood are considered environmentally friendly and sustainable due to their renewability and biodegradability. Natural fillers have other added advantages over artificial fibers in the sense that they have low specific weight, high specific strength and stiffness, safer handling and working conditions; they are also non-abrasive to the processing equipment (Tong et al., 2014).
Development of the oil sorbents made of organic waste materials was initiated in order to provide resources for marine oil spill response with less environmental load and cost (Masaki Saito et al., 2003). Sorbents of the oil spill in water are materials that soak up the oil. They can be used to recover oil through the mechanisms of absorption and adsorption, or both. Absorbents allow oil to penetrate into pore spaces in the material they are made of, while adsorbents attract oil to their surfaces but do not allow it to penetrate into the material. Once sorbents have been used to recover oil, they must be removed from the water and properly disposed of on land or cleaned for reuse. Any oil that is removed from the sorbent materials must also be disposed of or recycled. Sorbents can be divided into three basic categories: natural organic, natural inorganic and synthetic. The first category includes peatmoss, straw, hay, sawdust, ground corncobs, feathers, and other carbon-based products. They are relatively inexpensive and generally readily available. Organic sorbents can absorb 3 to 15 times their weight of oil, but they do present some disadvantages. Some organic sorbents tend to absorb water as well as oil, causing them to sink. Many organic sorbents are loose particles, such as sawdust, and are difficult to collect after they are spread on the water (Ghalambor, 1995).
Natural inorganic sorbents include clay, perlite, vermiculite, glass, wool, sand, and volcanic ash. They can absorb from 4 to 20 times their weight of oil. Inorganic substances, like organic substances, are inexpensive and readily available. Most organic materials can only be used on land and are not adaptable to water use for oil spill clean-up. Synthetic sorbents includes man-made materials that are similar to plastics, such as polyurethane, polyethylene, polypropylene, and nylon fibers. Most synthetic sorbents can absorb as much as 70 times their weight of oil. Synthetic sorbents that cannot be cleaned after use can present difficulties because they must be stored temporarily until they can be disposed of properly. They are best suited to absorb lighter viscosity oils that can perpetrate or wick into its fibre. Sorbents work by either absorption or adsorption (Ghalambor, A. 1995). Absorbents operate like sponges and collect oil by capillary action or suction. Adsorbents rely on the large surface area, the chemical affinity of the sorbents for the spilled oil, and chemical constituents including their porosity, molecular structure and change in volume. Absorbents work best on light, less viscous oils, while adsorbents work best on heavy, sticky, more viscous oils. In some cases, a sorbent material may utilize both techniques for oil recovery.