Natural fibers reinforced polymers, known as FRPs, have received a great deal of attention during the past decades 1,2. FRPs include lignocellulosic materials, such as wood, hemp, linens, corns stalks, coconut shells, peanuts shells, almond shells, wheat and rice straws, etc., as fiber or filler and thermoplastic or thermoset polymers as a matrix. Although the use of natural fibers is not as popular as the use of mineral or inorganic fillers, it has several advantages over traditional fillers and reinforcing materials such as low density, flexibility during the processing with no harm to the equipment, acceptable specific strength properties and low cost on per volume basis. Despite all these advantages, there are also serious concerns. The main disadvantage of using natural fibers as fillers is their high water absorption or desorption when subjected to changes in the relative humidity of the environment and low mechanical properties, mainly, due to highly hydrophilic nature of natural fibers that causes compatibility problems with the hydrophobic polymers in composites. Various approaches are used for the improvement of mechanical properties of composites. There are two major ways to improve mechanical

The main objective of this research was to study the potential uses of almond shell flour (ASF) in the production of thermoplastic composites containing montmorillonite (MMT). Thirty, 35, and 40 wt% ASF was used, and 2.0 wt% maleic anhydride-grafted polypropylene was used as the compatibilizer. Two levels of MMT nanoclay, 2.5 and 5.0 wt%, were mixed with polypropylene (PP). The effects of MMT on the thermal properties of the blended composites were evaluated using thermogravimetric analysis (TGA), morphological characterization, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The XRD data showed that the relative intercalation of the composites with 2.5 wt% MMT was higher than that of the 5.0 wt% nanoclay composites. The TGA results indicated that by increasing the MMT percentage, the degradation temperature and the thermal stability were enhanced. The MMT exhibited better dispersion in the clay layers of the polymer-matrix composites when increased from 2.5 to 5.0 wt%, and at the 5.0 wt% MMT loading, the size of MMT became larger. The total weight loss of the ASF/PP/MMT composite decreased as the filler content increased, and the thermal stability increased as the MMT content increased.

The effect of montmorillonite (MMT) loading (0, 2.5, and 5 wt%) and almond shell flour (ASF) content (30, 35, and 40 wt%) on the decay resistance, hardness, water resistance of injection molded polypropylene (PP) composites was investigated. The amount of maleic anhydride grafted polypropylene was kept constant at 2% for all formulations. White-rot (Trametes versicolor) fungal treatment was applied to the produced composites for 14 weeks according to BS 838:1961 with the Petri dishes method. The weight loss of the composites decreased with increasing MMT content. The highest hardness (66 Shore D) was noted in the undecayed control composites (40ASF60PP0MMT) while the lowest hardness (61.3 Shore D) was recorded in the decayed control composites (30ASF70PP0MMT). The water absorption of the undecayed and decayed composites decreased with increasing amount montmorillonite at 30-40 wt% content of the ASF loading level. The water absorption of the decayed composites was higher than that of the undecayed composites but their thickness swelling was lower. Based on the findings obtained from the present study, a 35/5/65/2 formulation of the ASF/MMT/PP/MAPP can be used in outdoor applications requiring a high dimensional stability.