A. Qaiss

Effect of Processing Conditions on the Mechanical and Morphological Properties of Composites Reinforced by Natural Fibres

In the last years, the exploitation of different natural fibres in the plastic industry has become increasingly essential for the introduction of new composites and products. The properties of polymers reinforced with natural fibre composites are generally governed by the fibre and matrix properties, the compatibility between the compounds, the process of treatment of fibres, and the manufacturing process of composites. Enhancements and innovations in manufacturing technology and assembly of fibre-reinforced polymer composite materials and structures are required to achieve the objectives of cost and performance to allow wider adoption in many sectors. In this chapter, natural fibres from doum, coir, and bagasse were added to polypropylene by twin-screw extrusion and molded by injection machine, to study the influence of manufacturing process especially during the extrusion and injection processes. The influence of extruder screw configuration (corotating and counterrotating), screw speed (60, 80, and 120 rpm), and temperature (190, 200, and 210 °C) was studied on the pressure of matter and torque, and then an optimized configuration was selected to evaluate the mechanical properties of injected composite. On the other hand, the preparation of the injected composite samples was performed by adopting different placing directions according to flow and tensile directions: parallel and transversal placements and the effect of fibre orientation in the mechanical properties of manufactured composites were evaluated. Advanced knowledge of the relationship between structure, composition, and characteristics of material composite based on natural fibres made possible the development of high-performance materials with excellent mechanical properties. We have demonstrated some aspects concerning the influence of the manufacturing process of the fibres in the thermoplastic matrix.

Characterization and Use of Coir, Almond, Apricot, Argan, Shells, and Wood as Reinforcement in the Polymeric Matrix in Order to Valorize These Products

The natural resource materials have an exceptional potential as reinforcement in plastic composites, due to their low cost, good mechanical properties, and biodegradability. This chapter is related to the use of some natural resources (nutshells residues) and their effect on polymer composite with varying filler reinforcement content and type or improving the adhesion between polymer matrix and filler. In this study, the used natural resources as bio-filler were almond shells, coir shells, argan shells, apricot shells, wood powder, and the mixture of these fillers, reinforcing thermoplastic polymer at various filler content (5, 10, and 20 wt.%), through extrusion and injection molding processes. The chemical and physical properties of the bio-filler and bio-filler/polymer composites were defined by using Fourier transform infrared spectroscopy (FT-IR); thermogravimetric analysis (TGA); differential scanning calorimetry (DSC); and tensile, torsional, and rheological tests. Depending on the bio-filler type, there was evidence that some particular difference in the chemical exists and also physical property changes. An increase in the crystallinity of composites is explained by the nucleating agent role of the bio-filler. The thermal, mechanical, and rheological properties of the composites were mostly enhanced with the addition of bio-fillers compared to the neat polymer matrix, and optimal properties were reached. Also, some optimal properties were observed when enhancing the interfacial adhesion by using a coupling agent. As a result, good final properties of the composites were manufactured with low cost. However, a fundamental understanding of the bio-filler structure and chemical composition could be beneficial to reach their full industrial applications.