Mechanical Properties, Microstructure and Surface Quality of Polypropylene Green Composites as a Function of Sunflower Husk Waste Filler Particle Size and Content

Agricultural waste is a still untapped source of materials that can,in case of proper utilization,significantly improve the sustainability of polymers and their composites.In this work,polymer composites based on isotactic polypropylene were produced incorporating ground sunflower husk in the amount of 10 wt%and 20 wt%.The work’s main objective is to evaluate how preliminary fractioning of this agricultural waste filler affects the thermomechanical properties,microstructure and surface topology of polypropylene-based injection molded composites.The composites were analyzed for mechanical properties(tensile,impact strength and hardness),thermomechanical properties(Vicat softening point VST,heat deflection temperature HDT,and dynamic thermomechanical analysis DMTA)with reference to morphological changes evaluated using scanning electron microscopy(SEM).The quality of the produced composites was assessed on the basis of the analysis of the surface topology of the injected composites.It has been shown that the larger particle size of used filler has a direct impact on increasing composite stiffness in the room and elevated temperature.Moreover,a relationship was demonstrated between the size of the filler and the deterioration of the tensile strength in the case of composites with a higher content of filler.The results show that the addition of sunflower husk as a particle-shaped waste filler is an effective method to increase sustainability of polypropylene-based green composites with beneficial thermomechanical properties and to reduce the residue of sunflower husk from industrial oil production.

Beneficial use of mussel shell as a bioadditive for TPU green composites by the valorization of an aqueous waste

Scientific studies have focused on environmentally friendly solutions as effective as the reuse of crop products owing to plastic-waste problems in recent years.This issue is the main driving force for upcoming academic research attempts in waste valorization-related studies.Herein,we integrated an aqua-waste,mussel shell(MS),as a bioadditive form into green thermoplastic polyurethane(TPU)green composites.Tuning of the MS surface was performed to achieve strong adhesion between composite phases.The surface functionalities of MS powders were evaluated via infrared spectroscopy and scanning electron microscopy(SEM)images.Composite samples were prepared by melt-compounding followed by injection molding techniques.It was confirmed by morphological analysis that relatively better adhesion between the phases was achieved for composites involving surface-modified MS compared to unmodified MS.Tensile strength and Young’s modulus of surface-modified MS-filled composites were found to be higher than those of unmodified MS,whereas the elongation at break shifted to lower values with MS inclusions.The shore hardness of TPU was remarkably improved after being incorporated with silane-treated MS(AS-MS).Stearic acid-treated MS(ST-MS)additions resulted in an enhancement in the thermal stability of the composites.Thermo-mechanical analysis showed that the storage moduli of composites were higher than those of unfilled TPU.ST-MS additions led to an increase in the characteristic glass transition temperature of TPU.Melt flow index(MFI)of neat TPU was highly improved after MS loading regardless of modification type.According to the wear test,surface modification of MS displayed a positive effect on the wear resistance of TPU.As the water absorption data of the composites were evaluated,the TPU/AS-MS composite yielded the lowest water absorption.The silane layer on MS inclusion promoted water repellency of composites due to the hydrophobicity of silane.The results of the biodegradation investigation demonstrated that adding unmodified and/or modified MS to the TPU matrix increased the biodegradation rate.The test results at the end of a 7-week period of biodegradation with a soft-rot fungus implied that the composite materials were more biodegradable than pure TPU.Silane modification of MS exhibited better performance in terms of the characterized properties of TPU-based composites.

Sustainable Biocomposites Materials for Automotive Brake Pad Application:An Overview

Research into converting waste into viable eco-friendly products has gained global concern.Using natural fibres and pulverized metallic waste becomes necessary to reduce noxious environmental emissions due to indiscriminately occupying the land.This study reviews the literature in the broad area of green composites in search of materials that can be used in automotive brake pads.Materials made by biocomposite,rather than fossil fuels,will be favoured.A database containing the tribo-mechanical performance of numerous potential components for the future green composite was established using the technical details of bio-polymers and natural reinforcements.The development of materials with diverse compositions and varying proportions is now conceivable,and these materials can be permanently connected in fully regulated processes.This explanation demonstrates that all of these variables affect friction coefficient,resistance to wear from friction and high temperatures,and the operating life of brake pads to varying degrees.In this study,renewable materials for the matrix and reinforcement are screened to determine which have sufficient strength,coefficient of friction,wear resistance properties,and reasonable costs,making them a feasible option for a green composite.The most significant,intriguing,and unusual materials used in manufacturing brake pads are gathered in this review,which also analyzes how they affect the tribological characteristics of the pads.

A comprehensive review on material selection for polymer matrix composites subjected to impact load

Polymer matrix composites(PMC)are extensively been used in many engineering applications.Various natural fibers have emerged as potential replacements to synthetic fibers as reinforcing materials composites owing to their fairly better mechanical properties,low cost,environment friendliness and biodegradability.Selection of appropriate constituents of composites for a particular application is a tedious task for a designer/engineer.Impact loading has emerged as the serious threat for the composites used in structural or secondary structural application and demands the usage of appropriate fiber and matrix combination to enhance the energy absorption and mitigate the failure.The objective of the present review is to explore the composite with various fiber and matrix combination used for impact applications,identify the gap in the literature and suggest the potential naturally available fiber and matrix combination of composites for future work in the field of impact loading.The novelty of the present study lies in exploring the combination of naturally available fiber and matrix combination which can help in better energy absorption and mitigate the failure when subjected to impact loading.In addition,the application of multi attributes decision making(MADM)tools is demonstrated for selection of fiber and matrix materials which can serve as a benchmark study for the researchers in future.