The increased attention to sustainable materials has triggered the progress of polymer composites in which plant-based fillers, i.e. jute, hemp, flax, coir, and abaca, are used to reinforce the materials. These materials which are given by biomass possess the benefits of low density, low cost, much more efficient in terms of renewability and also with less effect on the environment than the traditional synthetic reinforcements. Although these have these advantages, their further implementation is limited by natural hydrophilicity, low thermal stability, incompatibility with hydrophobic polymer matrices, and irregular material quality. The present review of literature offers critical insight into the chemical structure, functional group, mechanical, and thermal performance, surface treatments, and processing techniques of natural fillers. Such sophisticated methods of interfacial modification as graft polymerization is discussed as one of the effective techniques to improve adhesion and multi functionality. Its use in the automotive, aerospace, construction, packaging, and biomedical industries is tested, and such aspects of sustainability as a carbon footprint reduction and the potential of the circular economy are taken into account. Necessary technical issues and research directions are outlined in order to enable scalable and high-performance natural filler-based composite systems.

Polycaprolactone (PCL) is widely employed in fused filament fabrication (FFF) for biomedical applications; however, its mechanical strength, hydrophobic nature of the surface, and lack of antimicrobial property are the barriers to its wider use. The rice husk-derived amorphous silica (RH-SiO2), acquired through a sustainable waste valorization route was incorporated with PCL to fabricate multifunctional composites using FFF. The composite filaments with different contents of RH-SiO2 were extruded and printed, followed by a series of tests on melt flow behavior, dimensional stability, thermal characteristics, mechanical performance, wettability, in vitro degradation, and antibacterial activity. The results of microstructural analysis showed the filler was well dispersed. The optimal 2 wt% RH-SiO2 reinforcement led to an impressive enhancement of tensile strength (9.95 MPa), compressive strength (29.32 MPa), and surface hardness due to the synergistic effects of increased crystallinity and controlled melt rheology. The change in the contact angle showed a dramatic increase in wettability, while the results of degradation studies indicated that there was a balanced and stable degradation profile with very little pH variation. The printed PCL/RH-SiO2 composites has a compressive strength within the required range of trabecular bone, making it suitable for biomedical scaffold applications.

Recent developments in polymer science have provided good opportunities for developing composites reinforced by natural fibers. The superior sustainable and economical merits behind these composites make them much sought after in commercial and industrial applications. Besides being biodegradable and recyclable, they can be produced from renewable resources, thus providing good alternatives to synthetic fiber-reinforced materials. Along with their satisfactory mechanical properties, the adequate availability of abundant resources like flax, jute, and hemp only makes them appealing. This paper focuses on the classification, applications, and key mechanical and chemical properties of reinforced composites, highlighting their significant benefits in terms of ecological sustainability and material performance.

Present research focused on the addition of bio fibers (soyabean and corn) with bio fillers (coconut shell and walnut shell powder) and biopolymer (polylactic acid) for composite fabrication. Characterization of developed sample includes the hardness, tensile, flexural, and impact test. Outcomes evidently shows that addition of fillers and fibers enhanced the hardness value of composite specimen as compared to neat PLA composite specimen. Maximum hardness value of 98 Shore-D was achieved by SPW composite. Addition of walnut fillers achieved higher tensile strength of developed bio composites. Among all the developed bio composite specimens, SPW composite specimens achieved highest tensile strength of 57.82 MPa and neat PLA exhibits minimum tensile strength of 23.54 MPa. Incorporation of coconut filler with soyabean fiber and walnut filler with corn fiber gives better flexural strength as compared to other developed bio composites. SPC composite specimens achieved highest flexural strength of 59.59 MPa and neat PLA exhibits minimum flexural strength of 23.32 MPa. SPW composite achieved maximum impact strength of 18.8 Joule. At 25

Present research focused on the formation and effect of melamine–formaldehyde self-healing microcapsules on the mechanical performance of sisal, hemp and abaca reinforced epoxy composites. Self-healing microcapsules were formed by combining 3.12 g of melamine–formaldehyde and 0.75 g of copolymer in deionized water, followed by mixing the solution with bafflers inside a cylindrical vessel. In mechanical tests, Sisal/Epoxy/Self-healing Microcapsules (SESM) composite demonstrates the highest elongation at break of 9.21

In this study, biodegradable composites were prepared which were reinforced with pineapple fiber and fillers (coconut, eggshell and seashell) epoxy polymer resin. All prepared bio composite samples were characterized for thermal characteristics using thermogravimetric analysis (TGA) and chemical composition of fabricated samples were investigated using Fourier Transform Infrared Spectroscopy (FTIR). The study was focused on the effect of reinforced fillers on the thermal stability of prepared composites and their identification for absorbance peaks in FTIR analysis. Results of TGA show that all prepared composite exhibits the glass transition temperature between 250 and 275 °C. Pineapple/epoxy/seashell presents higher amount of residue as compared to pineapple/epoxy/coconut and pineapple/epoxy/eggshell composites. FTIR results revealed the presence of hydroxyl group and creation of hydrogen bonding by absorbance peaks between 3500 and 3900 cm−1 wavenumber. Absorbance peaks between 500 and 1500 cm−1 wavenumber proves the amount of cellulose, lignin and pectin in prepared composite specimens.

Mechanical, thermal, and structural improvements of natural fiber (Aloe vera and Eucalyptus) reinforced polylactic acid (PLA) composites with agro-waste fillers (Rice Husk and Wheat Husk) without and with maleic anhydride grafted polypropylene (MAPP) as a compatibilizer are reported in the present study. The composites comprise 70% PLA and 30% reinforcements, fillers, and MAPP. In hybrid composites, 70% PLA is combined with 10% fiber reinforcement, 10% fillers, and 10% MAPP. Ten formulations were produced and systematically investigated through measuring surface roughness, hardness, tensile, and flexural properties, impact strength, density, creep, fatigue, and thermal conductivity. The incorporation of MAPP had a substantial effect on fiber-matrix interface, contributing to the enhanced load transfer ability, dimensional stability, and energy dissipation. APWM and APRM had better tensile strength, fatigue performance was better, and flexural and thermal properties of EPWM and EPRM were good. Tensile, impact strength and creep resistance were also significantly improved in MAPP-modified composites. Composites with hybrid reinforcement were always better than those with either type of reinforcement or no reinforcement, indicating synergy in hybrid reinforcement. Although uncompatibilized and particulate-only composites showed moderate increase, they were still inferior to those of MAPP-modified counterparts. The results highlight the potential of lignocellulosic fiber-filler systems for the sustainable development of high-performance PLA composites. Morphological analysis of fractured surfaces was performed using scanning electron microscopy (SEM) to evaluate interfacial adhesion between the reinforcements and the polymer matrix.

In present work, tribology tests were enacted to analyze the wear behavior of composite reinforced with Aloe vera, Corn, Eucalyptus and Soybean Fiber and Epoxy resin. Fatigue and creep tests were accomplished to evaluate the strength of prepared composite specimen under fluctuating and static load conditions. Tribological analysis revealed that hybrid composites achieved higher frictional force as compared to single fiber-based composites. Hybrid ACESE composite exhibits maximum frictional force of 14.01 N, 35.78 N and 37.46 N at 10, 30 and 50 N load for 5 m/s sliding speed as compared to other prepared composite specimens. COF of prepared composite samples were calculated at different sliding speeds (3, 5 and 7 m/s) and applied load of 10, 30 and 50 N load. Hybrid ACESE composite shows maximum value of COF at 10, 30 and 50 N load for 3, 5 and 7 m/s sliding speed. Sliding speed (3, 5 and 7 m/s) with respect to applied load (10, 30 and 50 N) shows the variations in specific wear rate (SWR) for all prepared specimens. During tribological analysis, higher frictional force achieved by hybrid ACESE composite exhibits the highest value of interfacial temperature at 5 m/s sliding speed for 10, 30 and 50 N applied load. While the lower value of frictional force achieved by CE composite displays the lowest value of interfacial temperature at 5 m/s sliding speed for 10, 30 and 50 N applied load. The fatigue test illustrated that hybrid ACESE composite attained the highest fatigue number of cycles at 3822, 3217 and 2218 for 25, 50 and 75% UTS. While CE composites resulted in the lowest fatigue number of cycles at 2234, 1826, and 1219 for 25, 50 and 75% UTS among all prepared specimens.

Synthetic plastic-based products are very dangerous for human beings and the environment due to their toxicity during their whole life. Bio resources are the strong alternatives and cultivating more to form the composite materials due to their biodegradable and non-toxic nature. Humans are shifting from toxic plastic-based composites to natural bio fibers composites due to their main advantages of being biodegradable and having hydrophilic properties. Bio fibers are the material which can be attained by plants, crops, agricultural, or forestry wastages. The present study demonstrates the impact of flax fiber reinforcement on mechanical performance of developed flax/epoxy composites. Flax reinforcement was taken on 20, 30, and 40 by weight percentage with epoxy polymer matrix to develop the composite materials. Experimental testing of hardness, tensile, flexural, and Charpy Impact test methods were executed to analyze mechanical behavior of prepared composite specimens. Among all the developed composite specimens, 30wt.

The present study focused on the mechanical and water uptake behavior of composite materials made by natural fibers, epoxy resin, and natural nanoparticles. This study uses hemp and flax fibers with epoxy and with the addition of walnut shell powder and coconut shell powder as nanofillers. Hemp-reinforced nanocomposites absorbed more water as compared to other prepared specimens. Hemp-reinforced composites had the lowest value of surface roughness (Ra). The flax/epoxy composite specimen had the highest value of mechanical characteristics (tensile strength, Young’s modulus, and elongation at break) of 22.61 MPa, 2.0268 GPa, and 1.126 GPa, respectively. The flexural strength of the flax/epoxy/walnut shell was the highest at 52.87 MPa among all other composites. Flax fiber-reinforced composite has better mechanical strength, and the addition of walnut shell powder to flax/epoxy composites achieved maximum mechanical performance.

Present study investigates the possibilities of the effect of fillers (coconut and eggshell) on the fatigue, creep and tribological (wear and friction) performance of fibers (jute and flax) reinforced epoxy composites. The fatigue test results revealed that the Flax/Epoxy/Coconut Shell Powder composite exhibited the highest fatigue life and achieved maximum fatigue cycles at different ranges of the ultimate tensile strength (UTS), respectively, while the creep analysis demonstrated superior dimensional stability for the same composite. Frictional analysis revealed that all composite specimens exhibited maximum friction force values at an applied load of 50 N and a sliding speed of 5 m/s. The coefficient of friction was between 0.29 and 0.85 at a 3 m/s sliding speed and a 30N load for all the developed samples. Wear test results showed that a minimum SWR of 3.82 mm(3)/N-mm was achieved by JEE composite while maximum SWR was 15.08 mm(3)/N-mm by pure epoxy sample at 3 m/s sliding speed and 10 N applied load. JEC composite achieved the highest interfacial temperature among all prepared specimens at 15 degrees C, 36 degrees C, and 65 degrees C for 10, 30 and 50 N applied load at 5 m/s sliding speed. The Scanning electron microscopy appears in the presence of wear out surfaces after tribological test and helps to identify the failure mechanism after tribological performance. The morphological analysis of the FEE and FEC composites uncovered lengthened fracture patterns and broad matrix surface breakage. Additionally, fiber debonding and sliding during tribological analysis led to significant matrix damage.