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Polylactic acid (PLA) has gained significant attention as an environmentally friendly biopolymer, but its limited mechanical properties have hindered broader applications. Nanoparticles such as montmorillonite (MMT) offer a promising approach to address this limitation. The intercalation of MMT with polymer chains can significantly impact the mechanical properties of the nanocomposites. Hence, this paper investigated the effect of surface-modified montmorillonite (MMT) nanoparticles on the mechanical properties of polylactic acid (PLA) nanocomposites. The acetylation process of MMT was carried out followed by neutralisation process with NaOH. PLA granules and acetylated-modified MMT were mixed, crushed into granular form, and moulded. The effect of varying concentrations of modified MMTs on the tensile strength, elongation at break, and maximum force of PLA/MMT nanocomposites was evaluated using the ASTM D638 standard. FTIR results showed shifts in peak intensities in regions 2750 cm-1-2810 cm-1 led to changes in the aliphatic and aromatic regions, which confirmed the presence of acetylation. Controlled surface modification improved interfacial interactions and load distribution, enhancing overall mechanical performance. The incorporation of surface-modified MMT in PLA/MMT nanocomposite increased the maximum force, Young's modulus, elongation at breaks and tensile strength. PLA/1wt% MMT and the PLA/7wt% MMT compositions exhibited good mechanical properties. However, the PLA/5 wt% MMT blend is deemed more suitable for food applications, such as disposable cups, plates, and cutleries, due to its lower elongation point. In conclusion, the hydrophilic properties of MMT and the hydrophobic properties of PLA are compatible due to the synergistic effects during surface modification which enhance the overall performance of the nanocomposites. [ABSTRACT FROM AUTHOR]

The use of rice husks (RH) to reinforce polymers in biocomposites are increasing tremendously. However, the incompatibility between the hydrophilic RH fibers and the hydrophobic thermoplastic matrices leads to unsatisfactory biocomposites. Surface modification of the fiber surface was carried out to improve the adhesion between fiber and matrix. In this study, the effect of surface modification of RH via alkali, acid and ultraviolet-ozonolysis (UV/O3) treatments on the properties of composites recycled high density polyethylene (rHDPE) composites was investigated. The untreated and treated RH were characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The composites containing 30 wt% of RH (treated and untreated) were then prepared via extrusion and followed by compression molding. As compared to untreated RH, all surface treated RH exhibited rougher surface and showed improved adhesion with rHDPE matrix. Tensile strength of UV/O3-treated RH composites showed an optimum result at 18.37 MPa which improved about 5% in comparison to the composites filled with untreated RH. UV/O3 treatment promotes shorter processing time and lesser raw material waste during treatment process where this is beneficial for commercialization in the future developments of wood plastic composites (WPCs). Therefore, UV/O3 treatment can be served as an alternative new method to modify RH surface in order to improve the adhesion between hydrophilic RH fibre and hydrophobic rHDPE polymer matrix. [ABSTRACT FROM AUTHOR]

Biocomposites were prepared with rice husk flour (RHF) (raw and alkalitreated) in a recycled polymer blend (RPB) using a co-rotating twin screw extruder. Modifications to the composite were carried out through fibre surface treatment with 4 wt.% sodium hydroxide (NaOH) and 3 wt.% maleic anhydride polyethylene (MAPE) coupling agent. Fourier transform infrared (FTIR) analyses of raw and NaOH-treated RHF were performed. The effects of the interfacial modification (MAPE or/and NaOH) and filler loading (50 to 80 wt.%) on the mechanical, physical, and morphological properties were investigated. Improvements in the tensile strength and Young's modulus as well as reduction in water absorption and water loss were observed for raw RHF composites incorporated with MAPE. Alkalisation of fibres resulted only in an enhancement in elongation and impact strength. The composite with 70 wt.% RHF modified with only MAPE exhibited the highest tensile strength and modulus, 22.2 and 711.6 MPa, respectively. The general trend of the composite results exhibited some decrease in water absorption and water loss from untreated RHF composites with only MAPE modification as compared to the NaOHtreated composite, although a rougher surface for the treated fibres was revealed in SEM images. [ABSTRACT FROM AUTHOR]

Biocomposites of recycled high-density polyethylene (rHDPE)/recycled polyethylene terephthalate (rPET) matrices with a high loading of rice husk flour (RHF) were fabricated through a two-step extrusion. The use of ethylene-glycidyl methacrylate (E-GMA) copolymer improved the compatibility of the immiscible rHDPE/rPET blend. Maleic anhydride polyethylene (MAPE) was used as a coupling agent to increase the adhesion of the fibre–matrix interface. In this study, the effect of natural fibre loadings on rHDPE/rPET blends was examined. The water absorption process in the RHF-filled composites followed the kinetics and mechanisms of Fickian diffusion. Compared with samples without RHF, the rHDPE/rPET/RHF system had 58–172% higher tensile modulus and 80–305% flexural modulus. The thermal stability of the composites slightly increased with the addition of the RHF filler. The storage modulus of biocomposites was greatly enhanced by RHF. From these results, we can conclude that RHF can work well with rHDPE/rPET for manufacturing high loading biocomposite products. [ABSTRACT FROM AUTHOR]

ABSTRACT Rice husk flour (RHF) biocomposites based on uncompatibilized and compatibilized recycled high density polyethylene/recycled polyethylene terephthalate (rHDPE/rPET) with ethylene-glycidyl methacrylate (E-GMA) copolymer were prepared through a two-step extrusion and hot pressing with fiber loadings of 40, 60, and 80 wt %. Results showed that tensile and flexural properties increased. However, the elongation to break and impact strength decreased as the RHF loading increased. Compatibilizing polymer blend matrices can further enhance the mechanical properties. Water absorption (WA) test were examined in distilled and seawater. It is interesting to note that for composites made from uncompatibilized matrix, the calculated D and KSR were lower in seawater, but for the compatibilized matrix composites, the D and KSR obtained were generally lower in distilled water. However, compatibilization of rHDPE/rPET has been markedly reduced the WA and thickness swelling. Scanning electron microscope analysis of the compatibilized matrix composites confirmed the improved interfacial bonding of matrix-matrix and filler-matrix phases. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41494. [ABSTRACT FROM AUTHOR]

WPCs are being used in a large number of applications in the automotive, construction, electronic, and aerospace industries. There are an increasing number of research studies and developments in WPC technology involving rice husk as fillers. This study investigated the effects of different compositions of rice husk (RH) filler on the mechanical and morphological properties of recycled HDPE (rHDPE) composite. The composites were prepared with five different loading contents of RH fibers (0,10, 20, 30, and 40 wt%) using the twin screw extrusion method. Maleic acid polyethylene (MAPE) was added as a coupling agent. Results showed that tensile and flexural properties improved with increasing RH loading. However, the impact strength of the composites decreased as the RH loading increased. SEM micrographs revealed good interfacial bonding between the fiber and polymer matrix. [ABSTRACT FROM AUTHOR]