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

Abstract

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.

Injection molding of short coir fiber polypropylene biocomposites: Prediction of the mold filling phase

“…). The solidified polymer layer at the walls combined with the expanded central material leads to the pronounced curvature of the flow front centerline . It was also observed that the viscosity tends to be constant along the mold width as shear rate increases.…”

“…Although the mold temperature can be increased, this will increase the cooling cycle time so a compromise must be made. The distance that the material can flow (short shot) is also related to the processing conditions taking into account the rheological properties of each material . An optimized injection molding process requires an accurate control of several parameters such as the melt temperature, melt viscosity, shear rate, mold temperature, injection speed, injection pressure, and switch over point for speed and pressure to reduce the cycle time .…”

“…The distance that the material can flow (short shot) is also related to the processing conditions taking into account the rheological properties of each material . An optimized injection molding process requires an accurate control of several parameters such as the melt temperature, melt viscosity, shear rate, mold temperature, injection speed, injection pressure, and switch over point for speed and pressure to reduce the cycle time . These factors must be controlled for each formulation and requires a multidisciplinary/multivariable approach to optimize the final product performances .…”

“…An optimized injection molding process requires an accurate control of several parameters such as the melt temperature, melt viscosity, shear rate, mold temperature, injection speed, injection pressure, and switch over point for speed and pressure to reduce the cycle time . These factors must be controlled for each formulation and requires a multidisciplinary/multivariable approach to optimize the final product performances . These complex interactions between all the parameters must be related to the mold geometry and the melt flow properties.…”

“…This enables to improve parts quality as well as reducing production cost and time. Fortunately, experimental design can be used to reduce/eliminate lengthy experimental testing (trials and error) .…”