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This paper aims to fabricate a novel kenaf fiber, glass fiber, graphene composite reinforced with epoxy, and to study its water absorption, mechanical and machining properties. Natural fiber composites seek numerous applications nowadays due to its high strength is to weight ratio, high impact resistance, thermal stability, and recyclability. The literature study on natural fiber composites indicates lack of research on Kenaf fibers reinforced with E-glass fibers in conjunction with 0.5% and 1.0% of graphene. Hence, this research focuses on Kenaf fiber with percentage composition of graphene was varied as 0.5%, and 1.0%, by weight of the holding matrix and with/without incorporation of glass fiber. Suitable surface modifications were done by treating natural fibres by 0.5% NaOH for better adhesion of fibre and epoxy resin. Sonication and Cetyl trimethyl ammonium bromide (CTAB) treatments were also done to realize the fine scattering of graphene in the epoxy matrix in order to achieve better mechanical behaviour. Moulds were prepared as per D-638 ASTM standards. The treated fibres were then arranged in the mould by the conventional hand layup technique. The main objectives of this study are to conduct tensile, flexural, Impact, water absorption, machinability, and FTIR test. Result shows that the incorporation of graphene in natural fiber composites showed an increase in tensile strength, flexural strength, and water absorption properties by 27.7%, 53%, and 15% on average, respectively. The composites used in this research find their use in potential applications such as defence, biomedical aids, automobiles, packaging, actuators, etc. These often generate great interest, whenever there is a demand for fabricating lightweight and high strength material. [ABSTRACT FROM AUTHOR]

This study explores the synergistic influence of hybridizing titanium oxide (TiO2) filler on the mechanical properties and sliding wear behavior of epoxy composites reinforced with hairy cotton grass (HCG) fibres. The experimental results reveals that the combination with 9 wt‐% HCG/4 wt‐% titanium oxide observed better mechanical results (tensile‐51.03 MPa, flexural‐28.66 MPa, and impact energy‐3.1 J) whereas higher hardness (40.77 HV) achieved at 9 wt‐% hairy cotton grass/6 wt‐% titanium oxide composites. There is deterioration in mechanical results at higher titanium oxide (6 wt‐%) loading due to uneven distribution and particle agglomeration in hairy cotton grass‐epoxy composites. The design of expert was generated by using control parameters, sliding velocity (1 m ⋅ s−1–4 m ⋅ s−1), TiO2 content (0 wt‐%–6 wt‐%), and normal load (15 N–30 N) respectively. The optimization of the sliding wear rate was analysed by the Taguchi approach followed by an analysis of variance used for evaluating the significant of control parameters. The results showed a combination with significance sliding velocity of 1 ms−1 (78.15 %)>titanium oxide content of 6 wt‐% (20.28 %) >normal load of 30 N (1.57 %) exhibited an optimum value of specific wear rate. [ABSTRACT FROM AUTHOR]

The objective of this work was to produce and use green pea pod lignin for improving the thermal stability, flammability, and creep resistance of pineapple fibre-reinforced epoxy composite. The lignin macromolecules are derived from waste green pea pods via thermo-chemical process and used as reinforcement. The composites were made using the compression moulding method followed by post curing at 120°C. The prepared composites are then machined for testing according to ASTM standards. The results of this research demonstrate that the decomposition temperature of the composite known as EF is improved by the incorporation of pineapple woven mats by a volume of 40%. Comparing to all the composite designations, the EFL3 offers the least loss of weight, the highest decomposition temperature (approximately 420°C), the highest storage modulus (about 7.5 GPa), and the lowest loss tangent (0.6). Accordingly, the EFL3 composite designation has been reported to have the lowest combustion rate of 5.88 mm/min and the highest DSC value of 0.6 mW/mg. However, the creep strain is reduced when adding lignin by 0.5, 1.0, and 2.0 vol. %. These eco-friendly waste converted green pea pod lignin strengthened pineapple fibre-epoxy composites could be used in high thermal applications including automotive insulation panels and domestic infrastructure. [ABSTRACT FROM AUTHOR]

Natural fibre-reinforced hybrid polymer composites have gained significant attention worldwide in mechanical, aerospace, and automotive applications. Advanced machining techniques, such as abrasive water jet machining, have emerged as a solution to various challenges in this field, offering benefits such as the ability to shape complex geometries, achieve superior performance, improve surface characteristics, and attain high levels of accuracy. The research proposes a new approach for producing biodegradable hybrid composites composed of polylactic acid, bamboo particles, and montmorillonite clay using an innovative solvent-free stir-casting technique optimised for maximum efficiency. To systematically analyse the surface roughness, kerf angle, and material removal rate, a Box–Behnken design of experiments was employed, with the traverse rate, abrasive feed rate, and stand-off distance considered design variables. Analysis of variance was used to determine the significance of the differences between means of variables, while response surface methodology was utilised to establish the explicit relationship between the design variables and the response of the composite machining. The particle swarm optimisation algorithm was also employed to determine the optimal values of the design parameters for machining composites. The results showed that the traverse rate was the most influential factor, followed by the abrasive feed rate. In contrast, the stand-off distance had a relatively lower level of influence. The optimal process parameters were identified, resulting in a minimum surface roughness of 5.56 μm, a kerf taper of 0.0044 radians, and a material removal rate of 1175 g/min. [ABSTRACT FROM AUTHOR]

Selecting an appropriate Multi-Criteria Decision-Making (MCDM) method to provide a solution to assist design engineers in prioritising the right criteria in the early design process is essential. Part of the aim of this study is to establish an integration CRITIC-TOPIS for selecting the most efficient framework to choose performance criteria, namely density, tensile strength, Young's modulus, cellulose, and elongation at break for natural fibre material intended for cap toe shoes like abaca, bamboo, coir, jute, kenaf, sisal. Hence, a new framework was proposed and tested based on integrating Criteria Importance Through Inter Criteria Correlation (CRITIC)-Technique Order Preference by Similarity to Ideal Solution (TOPSIS). Therefore, this proposed framework consists of two phases: the first involves determining the weights of attributes using the CRITIC method, and the second consists of making material criteria decisions using the TOPSIS method. Meanwhile, to achieve this objective, numerical validation was obtained using data from selected past case studies, which were then replicated to validate the output of the proposed framework. According to the validation conducted using CRITIC-TOPSIS, the results show a significant level of similarity, with the rankings being consistent. Therefore, the proposed methodology may provide imprecise and ambiguous information for prioritising the performance criteria of natural fibre composite materials. Moreover, design engineers can utilise this framework in the composite industry to create the best possible evaluation model for composite material criteria selection for various applications. [ABSTRACT FROM AUTHOR]

Abstract This paper aims to fabricate a novel kenaf fiber, glass fiber, graphene composite reinforced with epoxy, and to study its water absorption, mechanical and machining properties. Natural fiber composites seek numerous applications nowadays due to its high strength is to weight ratio, high impact resistance, thermal stability, and recyclability. The literature study on natural fiber composites indicates lack of research on Kenaf fibers reinforced with E-glass fibers in conjunction with 0.5% and 1.0% of graphene. Hence, this research focuses on Kenaf fiber with percentage composition of graphene was varied as 0.5%, and 1.0%, by weight of the holding matrix and with/without incorporation of glass fiber. Suitable surface modifications were done by treating natural fibres by 0.5% NaOH for better adhesion of fibre and epoxy resin. Sonication and Cetyl trimethyl ammonium bromide (CTAB) treatments were also done to realize the fine scattering of graphene in the epoxy matrix in order to achieve better mechanical behaviour. Moulds were prepared as per D-638 ASTM standards. The treated fibres were then arranged in the mould by the conventional hand layup technique. The main objectives of this study are to conduct tensile, flexural, Impact, water absorption, machinability, and FTIR test. Result shows that the incorporation of graphene in natural fiber composites showed an increase in tensile strength, flexural strength, and water absorption properties by 27.7%, 53%, and 15% on average, respectively. The composites used in this research find their use in potential applications such as defence, biomedical aids, automobiles, packaging, actuators, etc. These often generate great interest, whenever there is a demand for fabricating lightweight and high strength material.

The experimental study of the physicochemical properties of biodegradable composite of sugarcane bagasse-polyester have been investigated. Natural composite materials having biodegradable property which makes them a material with limited lifespan, thereby there is a need to research on these materials beyond their normal scope before their lifespan for solid material applications as current technological concepts advances. In this research, water absorption, specific gravity, and chemical resistance test were conducted on sugarcane bagasse polyester composite of different specimen, using a laboratory beaker filled with distilled water, HCl, NaOH, H2O2, NaOCl and detergent solution, at a particular time observing a suitable ASTM. From the result obtained, specimen with 25 weights % increase in Sugarcane bagasse fibre loading, indicated water absorption value of 1.42 %, which could be acceptable for good resistance to water material. The chemical resistance test, severity of the attack and effect on the appearance and weight of the composites followed the order: 10% HCl > 10% NaOH solutions, the deteriorating effect of the composites showed to be unaffected by neither the amount of filler weight nor the presence of any additive incorporated in the SCB-PES composites.

This study evaluates the effects of sodium hydroxide (NaOH) treatment on tensile properties of sugar palm 'ijuk' (SPI) fibre-reinforced polymer (FRP) composites, with and without an open hole that acts as a stress concentrator. The NaOH treatment is aimed to improve the interfacial adhesion between SPI fibres and polymer matrix. Composite specimens were prepared using the hand lay-up method, incorporating SPI fibres in various orientations, and featuring a 6 mm diameter hole. Tensile tests were conducted to evaluate the mechanical performance of SPI FRP composite, including ultimate tensile strength, Young's modulus, and elongation at break. The research also compared the properties of SPI to those of synthetic glass fibre in fibre-reinforced polymer composites. The results showed that NaOH treatment significantly improves the fibre-matrix adhesion with 26% increase in tensile strength, leading to enhanced tensile properties in both samples, regardless of hole presence. The 0° orientation provides the highest strength and stiffness when the load is applied in the direction of the fibres. While for the 90° orientation, strength reduces by 14%. The impact of the hole on stress concentration and the subsequent mechanical behaviour of the open-hole specimens is substantial. The findings of this study offer insightful perspectives on the potential use of NaOH-treated SPI fibre in structural and other applications, demonstrating its ability to withstand tensile stresses, even with geometric discontinuities like holes. [ABSTRACT FROM AUTHOR]

This paper presents a numerical study of the influence of geometry and orientation of fibres on the mechanical behaviour of a hemp fibre reinforced polypropylene, obtained with injection. Tensile tests and multiplexing mode Dynamic Mechanical Analysis (DMA) were carried out in order to determine the mechanical behaviour of the neat and reinforced material. A numerical homogenization was then performed with the elastic hemp fibres for aligned and random orientation as well as a reconstructed microstructure obtained with injection simulation to correlate with tensile tests. The simulations were performed for sphero-cylinder and curved fibres and the results were compared to FFT results obtained directly on micro-tomography images as well as experimental data. The results showed that the complex geometry of the fibres can be approximated with a random 3D orientation of sphero-cylinder shaped fibres, a reasonable hypothesis leading to a simplification of the problem and an easier process of design of parts made with such materials. [ABSTRACT FROM AUTHOR]

This work involved an experimental study on Abaca fibre bio-composites subjected to a low-velocity impact test at 2.42 m/s to study the effect of fibre weight fraction on the impact performance. The abaca fibre reinforced composite (AFRC) specimens were fabricated with a 10% increment of fibre, varying from W f = 20% to 50%, and their impact properties compared with each other. The impact properties such as force-time history, energy-time history, Coefficient of Restitution (CoR), Energy Loss Percentage (ELP) and Energy Absorption Ratio (EAR) were studied. A significant change in impact force and energy absorption was found as the fibre content increased in the composite. The findings show a good relationship between fibre weight fractions, composite laminate stiffness, impact load and total absorbed energy. The experimental results of the impact test show that the composite specimen with W f = 40% has high impact energy absorption capacity with 4. 09 J 92.94 N and 4.09 J, EAR of 39.94%, CoR of 0.77 and ELP of 40.04%. Low fibre weight fraction composite has shown brittle failure, and high fibre weight fraction has shown ductile behaviour. Scanning electron microscopy (SEM) based study was used for post-impact damage analysis. [ABSTRACT FROM AUTHOR]

Polymeric foams are used in many applications, from packaging to structural applications. While polymeric foams have good mechanical performance in compression, they are brittle in tension and bending; fibre reinforcement can enhance their tension and flexural behaviour. This work reports a novel investigation of the mechanical properties of fibre-reinforced polyurethane (FRPU) foams with natural henequen fibres. Pull-out tests were performed with 10 mm fibres and various foam densities to identify the optimal density of 100 kg/m3. Thus, FRPU foams with this density and fibre contents of 1, 2 and 3 wt% were manufactured for mechanical testing. Compression tests showed an increase in the elastic modulus of the FRPU foam specimens compared to the unreinforced PU foam. The FRPU foams also exhibited higher yield stress, which was attributed to the reinforcing effect of the fibres on the cell walls. A maximum increase of 71% in the compressive yield stress was observed for the FRPU foam specimens with a fibre content of 2%. In addition, FRPU foam specimens absorbed more energy for any given strain than the unreinforced PU foam. Flexural tests showed the FRPU foams exhibited increased flexural strength compared to the unreinforced PU foam. A maximum increase of 40% in the flexural strength was observed for the FRPU foam with a fibre content of 1%. The findings reported here are significant because they suggest that FRPU foams incorporating natural henequen fibre exhibit promising potential as sustainable materials with enhanced mechanical properties. [ABSTRACT FROM AUTHOR]

To research the mechanisms of diffusion and water uptake kinetics biocomposites, various HDPE materials reinforced by varying quantities of Washingtonia filifera (WF) fibres (10 to 30 wt%) were submerged at room temperature in distilled water. To optimise the immersion time and WF fibre content in HDPE/WF biocomposite water uptake, an artificial neural network, the response surface methodology and the genetic algorithm were employed. In this research, the CCD model of RSM was utilised to carry out test design, modelling, and optimisation. It was found that the way water absorbs liquids follows the Fickian diffusion mode. The outcomes demonstrate that the incorporation of WF fibres into the HDPE matrix decreased the diffusivity. The ANOVA determined the relative significance of each variable and demonstrated the model's validity by demonstrating a high correlation between the observed data. Moreover, the results showed that the ANN models have training, test and validation correlation coefficients for water absorption prediction of 0.9955, 0.9915 and 0.9999, respectively. RSM-GA revealed that a 10% fibre content and a one-hour immersion duration produced the lowest levels of absorption. Additionally, a model that is very suitable for predicting biocomposites water uptake and is applicable to a variety of industrial applications is developed. [ABSTRACT FROM AUTHOR]

Environmental concerns and the depletion of petroleum resources have spurred research into natural fibres as sustainable alternatives to synthetic fibres as the reinforcement phase in polymer composites. Given that the local availability of materials is a crucial component in the sustainability framework, there is a need to map out the fibres used to develop natural fibre composites across geographical regions to optimize local resource utilization. Through a systematic review of publications sourced from Scopus and Web of Science databases, this study examines the contributions made by Africa to develop green polymer composites. The bibliometric data from both databases were systematically merged, and bibliometric analysis was carried out to identify trends and relevant relationships and provide a more general insight into Africa's progress in the natural fibre polymer composite field. A meta‐analysis was then conducted to identify the natural fibres exclusively sourced from Africa that have been used to develop polymer composites. The study also discussed natural fibre classifications with respect to fibre type and form. Sisal, palm varieties (particularly date palm), alfa, jute and members of the Musaceae family (i.e., banana, plantain and enset) were found to be the most used African‐sourced fibres. This study is a step to creating a more extensive global natural fibre database that seeks to provide more precise knowledge, enhance research efficiency, and ensure the utilization of local materials in creating more sustainable composites. Highlights: The use of local materials is a key component of sustainable developmentA natural fibre database can foster sustainability in the composite industryEgypt, Morocco, and Tunisia are leading Africa's composite researchResearch prioritizes composite material science over practical applicationsSisal, date palm, alfa and jute are the most used natural fibres in Africa [ABSTRACT FROM AUTHOR]

This study investigates the mechanical properties of hybrid composites composed of web kapok fibers and fiberglass reinforced with epoxy for potential application in the marine industry. The web kapok fibers were carefully processed using a carding technique to ensure better alignment and consistency. Various composite configurations were produced, and extensive mechanical testing was conducted, including flexural, tensile, and impact tests. The results revealed that the presence of two web kapok fiber layers within the composite significantly increased flexural strength and flexural modulus compared to pure fiberglass laminates. However, a single layer of web kapok fabrics exhibited the highest tensile strength, although it decreased with additional layers. The impact strength of these hybrid composites also showed promising results, especially when compared to raw fiberglass composites. Moreover, these composites exhibited improved resistance to water absorption and corrosion, making them potentially suitable for marine applications. This research highlights the potential of web kapok/fiberglass hybrid composites as an eco-friendly alternative for marine engineering, with implications for reduced environmental impact and sustainable technology in the industry. [ABSTRACT FROM AUTHOR]

Greener materials, particularly in sandwich panels, are in increasing demand in the transportation and building sectors to reduce environmental impacts. This shift is driven by strict environmental legislation and the need to reduce material costs and fuel consumption, necessitating the utilisation of more sustainable components in the transportation and construction sectors, with improved load-bearing capabilities and diminished ecological footprints. Therefore, this study aims to analyse and evaluate the structural performance of polyethylene terephthalate (PET) core and flax or basalt/flax FRP sandwich panels as an alternative to conventional synthetic materials. The novel eco-friendly sandwich panels were manufactured using the co-curing technique. Four-point bending, edgewise compression and core shear tests were performed and insights into how the skin properties affect the strength, stiffness and failure mode of specimens were provided. The stress–strain behaviour, facing modulus and strength, flexural rigidity, core shear strength and failure modes were evaluated. The flexural facing modulus of the flax and flax/basalt sandwich skins were found to be 5.1 GPa and 9.8 GPa, respectively. The flexural rigidity of the eco-friendly sandwich panel was compared with published results and demonstrated a promising structural performance. The environmental benefits and challenges were outlined and critically evaluated focusing on transportation and construction applications. [ABSTRACT FROM AUTHOR]

Natural fibre-reinforced polymer composite (NFRPC) has been introduced as one of the solutions to overcome the ecological and environmental problems accompanying the widespread usage of polymeric materials in every facet of life. However, the organic nature of both natural fibres (NFs) and polymers increases their flammability behaviour, and this, in turn, limits their application. In this regard, this work concentrates on studying the effect of adding flame retardants (FR) to jute-reinforced epoxy composites (JRECs), either by treating the jute fabric with diammonium phosphate (DAP) or adding DAP powder to the epoxy resin matrix on the flame retardancy performance as well as the mechanical properties. The results showed that the effect of the incorporation method of DAP either to jute fabric or to resin matrix has a significant difference on the flammability test results at low concentrations; however, at higher concentrations, the flame retardancy performance is not affected by the technique of adding FR to the composite system. On the other hand, the mechanical properties are significantly affected by the method of incorporating FR to JRECs at all concentrations. Moreover, the results obtained from JRECs with FR systems were evaluated and compared with the literature by constructing selection charts that relate the flame retardancy level to mechanical properties. [ABSTRACT FROM AUTHOR]

This paper presents the parametric investigation and optimization of various chemical treatment parameters that affect the mechanical performance of the green composite. The injection moulding method was used to produce the green composites using flax fibre (FF) and polylactic acid (PLA). The chemical parameters chosen to investigate their effects are chemical type (sodium hydroxide, sodium carbonate, and potassium hydroxide), chemical concentrations (1 %, 2 %, and 3 % (w/v)), and duration for fibre treatment (2 h, 4 h, and 6 h). The mechanical performance of the green composites was assessed by evaluating the various properties namely strength, modulus, and elongation under tensile, share, flexural, and compression loading conditions. The morphological study was also performed to examine the failure behavior of the composite after mechanical testing. The effect of fibre length (2 mm, 3 mm, 4 mm, 5 mm, and 6 mm) and fibre loading (10 wt.%, 20 wt.%, and 30 wt.%) on the performance of the flax fibre (FF)/polylactic acid (PLA) composite was also investigated. The fibre dispersion, fibre orientation, and fibre length retention were investigated to assess the characteristics of fibre during injection moulding of the developed flax fibre (FF)/polylactic acid (PLA) composite. [ABSTRACT FROM AUTHOR]

Pinus roxburghii needles are plentiful in the Himalayas and may be processed into a natural fibre. In this research, polylactic acid composites were made, including both untreated and treated Pinus roxburghii fibres as reinforcing materials. The Pinus roxburghii fibres were produced by subjecting the Pinus roxburghii needle to an alkali treatment with a 5% sodium hydroxide solution in water, and the Pinus roxburghii fibres were obtained by a water retting extraction method. Pinus roxburghii fibre–polylactic acid composites were made using a compression moulding process. Composites were fabricated utilizing treated and untreated Pinus roxburghii fibre with fibre loadings of 20%, 30%, and 40% by weight. Subsequently, the investigators examined the alterations in the tensile, flexural, impact, and morphological properties with sodium hydroxide treatment. As expected, alkaline treatment considerably boosted the compatibility between Pinus roxburghii fibre and polylactic acid, leading to improvements in the morphological, hardness, and mechanical characteristics of Pinus roxburghii fibre composites. In addition, when 30 wt.% of treated fibres were used, the mechanical characteristics improved. [ABSTRACT FROM AUTHOR]

Many researchers are interested in using natural fibres to treat due to recent advancements in polymer characteristics. The mechanical properties of three types of bars are studied in this paper: Cotton Fibre-Reinforced Polymer bars, Cotton/Carbon Fibre-Reinforced Polymer bars, and Cotton/Glass Fibre-Reinforced Polymer bars. The goal of the paper was to create low-cost bars with comparable mechanical performance and corrosion resistance to steel reinforcement. The bars were made using two methods: fibres immersed in polymer and fibres coated with polymer by repeated tension and relaxation of fibres. The second method produced better results in terms of the tensile strength of Cot.CFRP, Cot.GFRP, and Cot.FRP bars, which were 688, 477, and 284 MPa, respectively, and the stress–strain curve revealed brittle behaviour for all bars and modulus of elasticity of 43, 31 and 22 GPa. When sand was put on the bar's surface, the bars demonstrated a good connection with the concrete. It also showed good resistance to moisture, alkaline solutions and acids, as well as heat resistance at temperatures below 200°C. [ABSTRACT FROM AUTHOR]

Flax fibre-reinforced polymer was used to manufacture 27 tubes. A parametric study was conducted to investigate the effect of length and wall thickness on the tubes' bending capacity, strain behaviour, and failure mechanism which was investigated by conducting four-point loading experiments. The results indicated that with increasing the tube length, the failure mode of the tubes changed from ring-type deformation mode for short tubes to shear mode for medium-length and then to the bending mode for long tubes. While for short tubes, the largest strains developed in the hoop direction of the cross-section at mid-height, bottom, or top; for medium-length and long tubes, the largest strains occurred in the axial direction of the top or bottom cross-section. [ABSTRACT FROM AUTHOR]

The current review context elaborates on the engineering methods adopted by the researchers for the development of different sustainable flexible composites for use as an alternative to leather like material. This article also elaborates on the usage of different natural fibre-based cellulose, bacterial cellulose, and different plant-based compounds for the construction of leather like lifestyle products with the examination report of essential physical properties of engineered products. Besides, it elucidates the process conditions followed by the researchers for making natural fibre based flexible composite products. [ABSTRACT FROM AUTHOR]

Mineral carbonation is an effective CO2 sequestration approach and can be applied to cement-based materials through enforced carbonation curing. To accelerate this process, this study investigated the use of natural fibres (hemp, jute, cotton, and wool) to enhance CO2 transport in cement composites. Spun fibre yarns were added to cement pastes and subjected to enforced carbonation (20 vol% CO2) at 25 °C and 1 atm for 24–168 hours. Carbonation profiles were evaluated using two methods: phenolphthalein indicator coupled with image analysis, and thermogravimetric analysis (TGA). A novel image analysis method, based on colour deconvolution of phenolphthalein-stained images, was developed. Results from this method were consistent with those from TGA, offering a reliable and rapid technique for quantitatively assessing carbonation profiles of cement-based materials. The results confirmed that the natural fibre yarns created preferential CO2 transport pathways to facilitate CO2 uptake. Hemp yarns led to the most significant acceleration of CO2 transport, with carbonation fronts reaching 50 mm depths within 24 hours. Samples without fibres only showed superficial carbonation at the exposure surface. The findings of this study indicate the feasibility of using natural fibres to improve CO₂ sequestration in cement-based materials.

This study aims to develop sustainable, renewable and biodegradable biocomposite films from environmentally friendly materials. For this purpose, completely biodegradable polymer composites were prepared by mixing polylactic acid (PLA) with a new source, quince peel (QP), by solvent casting method, and their structural, mechanical and thermal properties were examined. The tensile strengths of the composites prepared using QP in proportions varying between 5% (P5Q) and 30% (P30Q) by weight vary between 21.13 ± 0.80 and 12.01 ± 0.10 MPa, and their elongations at break vary between 11.33 ± 0.38 and 4.08 ± 1.06 %. As the QP contribution increased, the tensile strength and breaking elongation of these composites generally decreased, while the elastic modulus also increased. Among these composites, whose elastic modulus varies between 1040.00 ± 140.01 and 811.33 ± 13.31 MPa, it was determined that the elastic modulus (1040.00 ± 140.01 MPa) of the 20% QP added composite (P20Q) was higher than the others. When the thermal analysis of PLA/QP films were examined, it was observed that the glass transition temperatures (Tg) were between 58.54 and 51.45°C and the melting temperatures (Tm) were between 167.71 and 164.28°C, and these temperatures generally decreased with increasing QP doping. When the T50 values, which represent the temperature at which 50% of the composite materials decompose, were examined, it was found that the QP-added ones were higher than the pure composites. While this value was 317.96°C in pure PLA composite, T50 values varied between 327.92 and 340.80°C depending on the varying QP ratios. According to the XRD results performed to evaluate the crystalline properties of PLA composites containing quince bark, the crystallinity of pure PLA was determined as 19.5% and the crystallinity of composites containing 5, 10, 20 and 30 wt % QP additives was determined as 19.3, 18.3, 16.4 and 14.6%, respectively. [ABSTRACT FROM AUTHOR]

The viability of incorporating agricultural by-products, such as oat husks, not yet explored in limestone-based composites, as more sustainable alternatives for use as novel aggregates may be improved through the adoption of well-known valorisation strategies applied to other plant-based resources. In this context, this work innovates by assessing how treatments on oat husk surfaces and the choice of limestone-based binders impact the mechanical performance of composites. The strategy adopted to achieve these objectives, in addition to carrying out the physical and geometric characterisation of the husks, consists of treating the husks' surface using washing cycles in water, cement/pozzolan binder, and linseed oil. Furthermore, matrices combining cement, calcium hydroxide Ca(OH)2, and microsilica (SiO2) were used. In conclusion, even though the effects of different binder combinations are inconsistent, coating oat husks—especially with linseed oil—works well in delaying particle degradation and improving mechanical strength compared to untreated particles. Furthermore, when aggregates are substituted with the longer and lamellar particles of oat husk, the impact of the water/cement ratio on mechanical performance and composite workability significantly decreases. [ABSTRACT FROM AUTHOR]

This study investigates the production and assessment of fracture toughness in Polypropylene (PP) composites reinforced with different weight fractions of treated and untreated coconut coir fibres. The potential of natural fibres, especially those obtained from agricultural waste like coconut coir, to create lightweight, affordable, and environmentally friendly composite materials has drawn attention. In the study, coir fibres were cleaned and chemically treated with NaOH before being incorporated into PP using injection moulding and extrusion techniques. According to ASTM guidelines, composites with 10%, 20%, and 30% coir fibre concentrations underwent Single Edge Notched Bend (SENB) testing to determine their fracture toughness. The fracture toughness of composites containing 10% and 20% untreated coir fibres was found to be higher than that of pure PP, but composites containing 30% untreated and all treated coir fibres showed reduced fracture toughness. The best composite, with 20% untreated coir, showed the best mix of fibre content and material performance, emphasizing how chemical treatment hurt fibre brittleness and the composites' overall ability to support loads. The potential of untreated natural fibres to improve composite materials for industrial applications- particularly in the automotive industry- is highlighted by this study. [ABSTRACT FROM AUTHOR]

A novel lightweight aggregate concrete (LWAC) or lightweight concrete (LWC) is developed using expanded perlite powder and lightweight expanded clay aggregate as a replacement for conventional fine and coarse aggregates, respectively. Furthermore, the natural plant-based flax fibre in treated form was added to the LWC mix at three different volume fractions. The mechanical and thermal characterisation of LWC was carried out using the compressive strength test, split tensile test, modulus of rupture, thermal conductivity and thermal resistance test. Moreover, the microstructural and durability properties were obtained using scanning electron microscopy/energy dispersive X-ray spectrum analysis, rapid chloride penetration test, sorptivity test and water absorption test. Test results reveal that the addition of 2.0% flax fibre resulted in improved mechanical, thermal and durability properties when compared to LWC with no fibres. Moreover, the microstructural analysis using SEM revealed the formation of ettringite which is responsible for the strength development in the LWAC mix. [ABSTRACT FROM AUTHOR]

This work aimed to investigate the low velocity impact behaviour of short jute fibre non-woven preform epoxy matrix composites experimentally. Dry fibre preforms were developed using an optimised process and a laboratory made preforming device. The effects of alkali and poly vinyl alcohol (PVA binder) treatments on impact performances of jute composites were investigated and compared at 3 J and 6 J impact energy levels. To identify the failure modes of tested composites, the X-ray µCT tomography was employed. The results demonstrated that the developed untreated short jute fibre preform reinforced composites absorbed a higher impact energy, when they were compared to treated (alkali or PVA binder) composites. For untreated composites, maximum impact forces at 3 J and 6 J energies, were found as ⁓2478 N and ⁓2319 N, respectively; for the PVA treatment these values were measured as ⁓2457 N and ⁓2216 N, while, at same energy levels, alkali treated composites showed the lowest values as ⁓1683 N and ⁓1440 N, respectively. Untreated jute fibre contains natural matrices such as hemicellulose, lignin and waxes, which ensured a positive response to absorb more energy upon impact loading. In contrast, the alkali treatment facilitates a highly fibre packed composite structure, which accelerated the impact crack propagation in tested composites, resulting in lower resistance to impact energy. Although, PVA treated composites showed reduced impact properties compared to untreated composites due to the PVA polymer brittleness on the treated fibre surface during the impact incidents, this treatment demonstrated better impact responses over the alkali treatment. The application of PVA binder on alkali-treated fibres provided an extra support to fibres and a better fibre/matrix interface and hence, this combined treatment demonstrated a slightly better impact resistance (⁓2027 N and ⁓1874 N impact forces at 3 J and 6 J respectively) compared to only alkali treated fibre composites. The SEM fracture images and the X-ray µCT damage analysis revealed different impact damage modes, which supported the observed impact results. The obtained results from this investigation could be helpful for using short jute fibre composites in various load demanding applications where impact incidents are likely to be happened.

Abstract There has been an increase in research over the past decades into the use of environmentally friendly materials in brake pads, such as natural fibres. This is due to the possibility that natural fibbers could serve as an alternative to the noxious asbestos materials in tribological applications like brake pads. As a result, utilizing the compacting mould technique, an asbestos-free friction material was developed using agricultural waste (coconut shell and oil bean stalk) as a filler element, alongside aluminium dross, metal chip industrial wastes and carbon black. The filler material considered had particles as small as 300 μm, with epoxy resin serving as the binding agent. Using these waste materials can help reduce environmental pollution and the risk to animal and plant life (Preeti et al., Pharma Innov J 7:94–102, 2018; Sajib, A Study on the effects of environmental pollution on human life in the riverbank area of Barishal City Corporation (Kirtankhola River), 2021). This research aimed to replace asbestos in brake pads due to its carcinogenic nature, reducing the health risks associated with manufacturing and using these brake pads. The brake pad materials were cast and produced using square wooden moulds. Four samples were created, comprising the same mixing ratio but varying in reinforcement fibre and particle size, with epoxy resin used as the matrix. Various tests were conducted on these samples, including a water absorption test, specific gravity test, compressive strength test, hardness test, thermal conductivity, SEM and EDX. The developed brake pads underwent microscopic characterization and structural examination using a scanning electron microscope (SEM) fitted with energy-dispersive X-ray spectroscopy (EDX) for elemental characterization. Thermal conductivity was obtained using automated Lee’s Disc apparatus. Comprehensive strength analysis was conducted using a universal testing machine (UTM). The specific gravity tests yielded values for the developed composites in the range of 1.136–1.257, while the commercial brake pad had a value of 2.081, indicating that the produced samples were lighter and less dense. The water absorptivity of the developed samples ranged from 0.95 to 2.174%, while the commercial brake pad had a value of 1.031%. For the hardness tests, at three different loads, the developed values ranged from 16.4HV3 to 19.4 HV3; 26.4HV30 to 28.7HV30; and 25.5HV100 to 29.6HV100, while the commercial brake pad had values of 16.5HV3, 28.4HV30 and 28.2HV100. Sample C (212 μm: coconut shell powder) exhibited the most desirable characteristics with five values: water absorptivity 0.95, compressive strength 120.5 MPa, hardness value 29.6 HV100, wear resistance 0.099 mm/mm3, specific wear rate 1.00 mm3/Nm. The outstanding values were attributed to the chemical composition, particle sizes and good interfacial bonding of the microstructure. The developed brake pads performed favourably when compared with the existing commercial brake pads. The chemical tests showed that the natural fibres bonded well with the epoxy matrix. The thermal and mechanical tests yielded comparable results with the values obtained from the commercial brake pads. Therefore, the developed materials for brake pads can be considered suitable replacements for asbestos brake pads.

Recent decades have seen a substantial increase in interest in research on natural fibres that is aligned with sustainable development goals (SDGs). Due to their renewable resources and biodegradability, natural fiberreinforced composites have been investigated as a sustainable alternative to synthetic materials to reduce the usage of hazardous waste and environmental pollution. Among the natural fibre, jute fibre obtained from a bast plant has an increasing trend in the application, especially as a reinforcement material. Numerous research works have been performed on jute fibre with regard to reinforced thermoset and thermoplastic composites. Nevertheless, current demands on sustainable materials have required new developments in thermoplastic composites. In this paper, the author reviews jute plants as reinforcement materials for thermoplastic matrix polymers. This review provides an overview of the sustainability of jute plants as reinforcement material for thermoplastic matrix polymers. The overview on jute based thermoplastic composites focused on the thermal behavior and mechanical properties. Apart from physical, chemical, and mechanical properties, the study also covers the current and perspectives for future research challenges faced by the researchers on jute fibre reinforced thermoplastic composites. [ABSTRACT FROM AUTHOR]

Biofibres' wide application in mortar enhancement has thus far been restricted by factors related to their chemical composition and hygroscopic nature. Their hydrophilic behaviour increases the water demand of mortar mixtures and diminishes their affinity to the matrix, while further moisture-related fibre degradation issues may arise. Additionally, natural fibres seem to be susceptible to degradation caused by exposure to alkaline environmental conditions such as those experienced by cement mortars, restricting their utilisation in the construction industry. Therefore, the current study investigates the potential of fibre modification through treatments that would permanently alter their structure and chemical composition to improve their performance. In this study, wood fibres of black pine and beech species were exposed to mild thermal treatment (140 °C 2 h, under a steam atmosphere), characterised in terms of the physical and chemical properties and incorporated in cement mortars, applying the proportion of 1.5% v/v in the mortar, in order to assess their performance as reinforcement material. The mortars' workability (at a fresh state) was examined, as well as other physical, hygroscopic, thermal, and mechanical characteristics of the mortars at the ages of 28, 90 and 365 days and weathering performance, by subjecting them to different artificial ageing environments (freeze–thaw cycles or outdoor exposure). The results revealed the beneficial role of the treated fibres in dimensional stability, flexural strength, thermal insulation properties and capillary absorption of the mortar specimens, especially during the ageing process, with the black pine fibres showing the greatest improvement. The hydrothermally treated wood fibres seem to help maintain the integrity of cement mortars under all ageing conditions, proving that they could provide low-cost and eco-friendly mortar enhancement pathways. [ABSTRACT FROM AUTHOR]

In this present investigation, a new attempt was made to produce sustainable polyester-based biocomposites using Lansium parasiticum fruit shell powder and hemp chopped fibre. The main objectives of this investigation were developing biocomposite and studying its mechanical, wear, water absorption and flammability properties. The powder was produced from waste fruit shell via ball milling process whereas the fibre was used in as-received form. The biocomposites are prepared using a hand layup method where post-curing is applied at 110 °C at the end of the process. The results revealed that the addition of fibre and filler improved the mechanical properties. A maximum tensile and flexural strength of 98 MPa and 143 MPa were noted for composite having 3 vol% filler and 40 vol% of fibre. Similarly, the addition of filler into the resin reduced the wear coefficient as well as wear loss. A lowest sp. wear rate of 0.009 mm3/Nm was recorded for composite made with 5 vol% of filler. But the water absorption and flammability were found to be affected marginally upon cellulosic fibre and filler addition. Nonetheless, they are in acceptable range indicating better hydrophobicity and low flammability. As a verdict, the combination of hemp fibre and Lansium parasiticum fruit shell powder along with polyester resin could be a noteworthy combination to form biocomposites with less cost, more eco-friendly and sustainable and circular economy concerns. Moreover, this practice could create a habit of producing sustainable eco-friendly products from waste, thus reducing the severity of solid waste accumulation. These new generation waste-derived biocomposites could be used as functional working material in applications starting from domestic to high performance engineering sectors. [ABSTRACT FROM AUTHOR]