This study explores the possibility of developing a new class of hybrid particulate-filled biocomposites using wood flour and rice husk wastes as environmentally friendly additives to poly(lactic acid) (PLA) as matrix material. Samples were prepared with fillers of different concentrations (0, 2.5, 5, 7.5 and 10 wt %), while the ratio of wood flour and rice husk was fixed at 1:1 in all cases. The preparation of biocomposites was performed through extrusion using a twin-screw extruder. Subsequently, they were formed into specimens by injection molding. Mechanical, thermal, thermomechanical, and morphological properties were examined. The addition of natural waste particles resulted in a remarkable improvement both in tensile and flexural modulus; however at a cost of impact strength and tensile strength. Meanwhile, flexural stress at conventional strain values were barely affected by the presence of wood flour and rice husk. The SEM images confirmed that there is a limited interfacial adhesion between the components, which supports the results obtained during mechanical tests. Both the differential scanning calorimetry (DSC) and the dynamic mechanical analysis indicated that the glass transition temperature of PLA was not affected by the incorporation of filler particles; however, the crystalline structure was gradually altered with increasing filler loading according to the DSC. Additionally, the particles were observed acting as nucleating agents, thereby increasing the overall crystallinity of PLA.

The objective of this work is to evaluate the effect of maleic anhydride-grafted polypropylene (MAPP) as coupling agent in polypropylene (PP)-based composites filled with ground wheat straw (WS) particles. The WS and the MAPP content in the composites was 10 wt% and 2 wt%, respectively. The samples were fabricated through melt compounding using a twin-screw extruder and then formed into dumbbell-shaped specimens by injection molding. The mechanical properties of neat PP and the composites with and without coupling were evaluated based on tensile and flexural tests and dynamic mechanical analyses (DMA). The experimental results showed that incorporating WS into the PP reduces its tensile strength by ~3 MPa, while improving its Young’s modulus by 0.14 GPa. The addition of MAPP compensated for the loss in tensile strength without affecting the modulus. Similar observations were made during the flexural tests as well, in which case, however, there was no loss revealed in the strength in the presence of WS due to the different types of load. The results of DMA analyses indicated an improved stiffness of WS-containing samples throughout the whole analyzed temperature range of 20-120 °C as a consequence of reduced chain mobility of PP caused by the stiff straw particles.

In our study, the effects of wood waste content (0, 2.5, 5, 7.5, and 10 wt.%) on thermal and dry sliding wear properties of poly(lactic acid) (PLA) biocomposites were investigated. The wear of developed composites was examined under dry contact conditions at different operating parameters, such as sliding velocity (1 m/s, 2 m/s, and 3 m/s) and normal load (10 N, 20 N, and 30 N) at a fixed sliding distance of 2000 m. Thermogravimetric analysis demonstrated that the inclusion of wood waste decreased the thermal stability of PLA biocomposites. The experimental results indicate that wear of biocomposites increased with a rise in load and sliding velocity. There was a 26–38% reduction in wear compared with pure PLA when 2.5 wt.% wood waste was added to composites. The Taguchi method with L25 orthogonal array was used to analyze the sliding wear behavior of the developed biocomposites. The results indicate that the wood waste content with 46.82% contribution emerged as the most crucial parameter affecting the wear of PLA biocomposites. The worn surfaces of the biocomposites were examined by scanning electron microscopy to study possible wear mechanisms and correlate them with the obtained wear results.

Designing excellent hip implant composite material with optimal physical, mechanical and wear properties is challenging. Improper hip implant composite design may result in a premature component and product failure. Therefore, a hybrid decision-making tool was proposed to select the optimal hip implant composite according to several criteria that are probably conflicting. In varying weight proportions, a series of hip implant composite materials containing different ceramics (magnesium oxide, zirconium oxide, chromium oxide, silicon nitride and aluminium oxide) were fabricated and evaluated for wear and physicomechanical properties. The density, void content, hardness, indentation depth, elastic modulus, compressive strength, wear, and fracture toughness values were used to rank the hip implant composites. It was found that the density and void content of the biocomposites remain in the range of 3.920–4.307 g/cm³ and 0.0021–0.0089%, respectively. The composite without zirconium oxide exhibits the lowest density (3.920 g/cm³), while the void content remains lowest for the composite having no chromium oxide content. The highest values of hardness (28.81 GPa), elastic modulus (291 GPa) and fracture toughness (11.97 MPa.m^1/2) with the lowest wear (0.0071 mm³/million cycles) were exhibited by the composites having 83 wt.% of aluminium oxide and 10 wt.% of zirconium oxide. The experimental results are compositional dependent and without any visible trend. As a result, selecting the best composites among a group of composite alternatives becomes challenging. Therefore, a hybrid AHP-MOORA based multi-criteria decision-making approach was adopted to choose the best composite alternative. The AHP (analytic hierarchy process) was used to calculate the criteria weight, and MOORA (multiple objective optimisation on the basis of ratio analysis) was used to rank the composites. The outcomes revealed that the hip implant composite with 83 wt.% aluminium oxide, 10 wt.% zirconium oxide, 5 wt.% silicon nitride, 3 wt.% magnesium oxide, and 1.5 wt.% chromium oxide had the best qualities. Finally, sensitivity analysis was conducted to determine the ranking’s robustness and stability concerning the criterion weight.

The aim of this present work was to study the applicability of waste marble dust (MD) in poly(lactic acid) (PLA)-based composites. Samples containing up to 20 wt% waste MD were prepared via melt blending. The attention was focused on the investigation of mechanical, morphological, thermal properties and the wear resistance of the PLA/MD composites. Regarding the mechanical properties, both the tensile and the flexural modulus improved remarkably, however, a slight loss was observed in strength and deformability. The impact toughness showed an increasing tendency up to 10 wt% MD loading, which was followed by a marginal decrease at higher concentration. With respect to the sliding wear rate, the composite with the highest MD content showed the best wear resistance. According to the DSC measurements, the MD hampered the chain mobility of PLA, thereby reducing the crystalline ratio. Overall, composites with improved properties were developed, while the reuse of waste MD is expected to reduce the production costs as well.

The aim of the research work is to study the physical, mechanical, and erosive wear properties of sugarcane bagasse fiber-reinforced epoxy composites. The physical (density, void content) and the mechanical (hardness, tensile strength, impact energy, flexural strength) properties of the composites were found to increase with the content of bagasse fiber. For erosive wear analysis, the experiments were carried out with the help of erosion test machine. To minimize the erosive wear rate, Taguchi technique is executed to explore the influence of five control factors including fiber content, impact velocity, impingement, stand-off distance, and erodent size at three levels. Using Taguchi (L27) orthogonal array, the optimal combination of control factors, which yielded minimum erosive wear rate, was statistically predicted and experimentally verified. The fiber content and impact velocity were the two most contributing control factors for the minimization of erosive wear rate. The important sequence of the parameters is fiber content > impact velocity > impingement angle > erodent size > stand-off distance. The optimal combination of control factors was obtained at 10 wt% of fiber content, 30 m/s of impact velocity, 30° of impingement angle, 85 mm of stand-off distance, and 250 μm of erodent size. Finally, composites worn surfaces were examined with scanning electron microscope to study the possible erosive wear mechanism. POLYM. COMPOS., 40:3777–3786, 2019. © 2019 Society of Plastics Engineers.