Composite production of polypropylene polymers was considered in this work as the matrix, filled with the fiber of wheat straw and paper mill sludge; different ratios were evaluated relative to their potential as reinforcement materials. Maleic anhydride polypropylene (MAAP) was used at 3% by weight. The bending modulus of elasticity of the composites significantly increased with both types of filler. The highest bending modulus of the composites was found with 40% of paper mill sludge. Using 40% wheat straw fiber decreased bending strength, but the addition of paper mill sludge increased bending strength. The highest bending strength of the composites related to polypropylene/10% of wheat straw fiber and 30% of paper mill sludge. In terms of impact strength, the use of paper mill sludge had a higher impact on strength than wheat straw fiber composites. The inclusion of MAPP improved the mechanical properties of all composites. Scanning electron micrographs showed that the composite paper mill sludge improved the adhesion and dispersion of the filler (paper mill sludge/fiber paper instead of wheat) in the matrix.

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.

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Wood plastic composites have received increasing attention during the last decades, because of many advantages related to their use. However the durability of Wood plastic composites after ultraviolet exposure has become a concern. In this research, hybrid nanocomposites of polyethylene and woodflour with different concentrations of nanoclay were fabricated using melt compounding followed by injection molding. Specimens were exposed for 2000 h to ultraviolet radiation and moisture cycling in a laboratory weathering device to simulate the effects of exposure to sunlight and rain. Physical and mechanical properties of the nanocomposites were evaluated, before and after weathering. The results indicated that the water absorption of wood plastic composites increased after weathering but nanoclay reduced the intensity of weathering to some extent, through decreasing of water absorption. Also results showed that weathering decreased modulus of elasticity values, however good dispersion of clay layers resulted in fewer drop of modulus of elasticity values. Fourier transform infrared spectroscopy showed that lowest carbonyl index is related to the nano wood plastic composites with 2wt% nanoclay. Also X-Ray diffraction patterns revealed that intercalation morphology has been formed for nano particles.

Recently, the use of nanoparticles in Wood Plastic Composites (WPCs) has been considered by researchers. In this study, Multi-Walled Carbon Nanotubes (MWCNTs) were compounded with PVC, wood-flour, and foaming agent in an internal mixer. The wood flour amount was constant at 40 phr. For CNT and chemical foaming agent , different levels of 0, 1, 2 phr and 0, 3, 6 phr were considered respectively. The samples were foamed via batch process using a compression molding machine at 180°C. Morphology, density, water absorption, thickness swelling, and tensile properties of foamed composites were evaluated as a function of CNT and chemical foaming agent contents. The experimental results indicated that in the presence of CNT, cell density increased and cell size decreased. Density of the foamed composites was not affected by chemical foaming agent contents. Water absorption and thickness swelling of samples were decreased as compared with wood plastic composite without CNTs. Also, the maximum tensile strength and modulus were increased by up to 20% and 23% respectively.