This review paper explored the mechanical and thermal characteristics of hybrid composites by emphasising their performance using different types of fibres. This work also examines various kinds of biofibres and synthetic fibres reinforced with other polymers, focussing on how these composites behave in moisture conditions. Although hybrid fibres offer a variety of benefits, the hybridisation of natural and synthetic fibres poses challenges: increased moisture absorption, poor fibre-to-matrix adhesion bonding, and limited heat resistance. Fibre surface modification treatments can overcome these challenges. Thus, the hybridisation of natural-natural, natural-synthetic and synthetic-synthetic fibres, offers a wide range of applications in the automotive industry, 3D printing, military equipment, construction, and building industries, among others. This study highlights the current efforts using hybrid materials in different characterisation techniques, predominantly mechanical, thermal, and moisture absorption behaviours, which have helped address the current challenges and improved their performance in various fields.

Mechanical properties were evaluated for bio-natural fiber-reinforced epoxy hybrid composites made with varying amounts of jute, banana stem leaves (BSL), and tamarind shell powder (TSP). Each composite design had varying weight percentages of jute and BSL (5 to 25%) and a consistent mix of TSP (10%) and epoxy resin (60%). The tensile strength, flexural strength, interlaminar shear strength (ILSS), impact strength, hardness, and water absorption were examined. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to investigate chemical bonding and morphology. The findings indicated a relationship between fiber and filler content and mechanical properties of composites, with 20% jute fiber content resulting in the highest performance. The tensile strength of the composite increased by 24.6%, rising from 32.4 MPa for the 5% jute and 25% banana stem leaves (5J25BSL) composite to 40.4 MPa for the 20% jute and 10% banana stem leaves (20J10BSL) composite. Similarly, the flexural strength saw a 27.9% improvement, increasing from 67.2 MPa in the 5J25BSL composite to 86.0 MPa in the 20J10BSL composite. The impact strength also experienced a notable increase of 39.1%, moving from 2.56 J for the 5J25BSL composite to 3.56 J for the 20J10BSL composite. These results highlight significant improvements in all three properties, as the proportion of jute in the composite increased and the proportion of banana stem leaves decreased. This research influences material selection for engineering applications and informs the development of specialized composite materials.

The present work centers on aluminum-based metal matrix composites (AMCs), synthesized via stir casting and then processed by electrical discharge machining (EDM) in the case of Al7075 as a matrix and 6 wt.% boron carbide (B4C) as reinforcement. A design of experiment (DoE) approach, powered by hybrid optimization techniques (such as the entropy weight method (EWM), grey relational analysis (GRA) incorporated Taguchi method) was used to investigate the relationship between current (I), pulse ON time (Ton), pulse OFF time (Toff), and electrode gap (Gap) as input parameters and the material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) as response parameters. The results showed that an I = 140 A, Ton = 120 ms, Toff = 50 ms, and Gap = 0.4 mm combination gives the best response parameters of MRR = 0.5628 mm3/min, TWR = 0.0048 mm3/min, and SR = 4.4034 μs.

High performance and durability are essential for goods to satisfy the needs of the expanding worldwide market. Wood plastic composites (WPCs) are materials made from a combination of wood, polymers, and additives. WPCs can be extruded, injected, compressed, or thermoformed. Presently, WPCs are manufactured using sophisticated processes including as laser sintering, fused layer modeling, and additive manufacturing. Properly managing the melt temperature and pressure is crucial in the manufacturing process of WPCs to ensure effective polymer incorporation. Natural fibers have distinct benefits for polymer composites, but they also have some serious drawbacks, like lower strength properties—especially lower impact strength than synthetic fibers—poor compatibility with hydrophobic polymers, poorer dimensional stability and moisture absorption due to hydroxly groups, a maximum processing temperature that is limited, thermal degradation above 200–220°C, and lower biological durability. The modification of the surface of the fibers improves the mentioned disadvantages of the natural fibers. High‐quality WPCs require the application of chemical or physical treatment to the wood fibers. This extensive review focused on the modification techniques applied to the surface of wood, manufacturing processes, and properties and applications of WPCs. Highlights Modification methods used in surface treatment of natural fibers was explained. Properties and recent applications of wood polymer composites were given. Optimum requirements of natural fibers and polymer matrices are given. Fabrication methods of natural fiber composites are extensively given.

High performance and durability are essential for goods to satisfy the needs of the expanding worldwide market. Wood plastic composites (WPCs) are materials made from a combination of wood, polymers, and additives. WPCs can be extruded, injected, compressed, or thermoformed. Presently, WPCs are manufactured using sophisticated processes including as laser sintering, fused layer modeling, and additive manufacturing. Properly managing the melt temperature and pressure is crucial in the manufacturing process of WPCs to ensure effective polymer incorporation. Natural fibers have distinct benefits for polymer composites, but they also have some serious drawbacks, like lower strength properties-especially lower impact strength than synthetic fibers-poor compatibility with hydrophobic polymers, poorer dimensional stability and moisture absorption due to hydroxly groups, a maximum processing temperature that is limited, thermal degradation above 200-220 degrees C, and lower biological durability. The modification of the surface of the fibers improves the mentioned disadvantages of the natural fibers. High-quality WPCs require the application of chemical or physical treatment to the wood fibers. This extensive review focused on the modification techniques applied to the surface of wood, manufacturing processes, and properties and applications of WPCs.Highlights Modification methods used in surface treatment of natural fibers was explained. Properties and recent applications of wood polymer composites were given. Optimum requirements of natural fibers and polymer matrices are given. Fabrication methods of natural fiber composites are extensively given. Process of wood plastic composites (WPC). image

Over the past decade, significant progress has been made in creating environmentally friendly products using natural resources. Plant fibers, also known as lignocellulosic fibers, are hydrophilic due to the interaction and attraction between water molecules and the hydroxyl groups present in their components. The inherent hydrophilicity of plant fibers often prevents them from interacting effectively with hydrophobic polymer matrices. In order to improve the adhesion between plant fibers and the matrix, it is necessary to modify the surface of the fibers. Commonly used chemical processes include mercerization, silane treatment, acetylation, permanganate treatment, acrylation, benzoylation, peroxide treatment, stearic acid treatment, isocyanate treatment and sodium chlorite intervention. The desirability of chemically modifying the surface of plant fibers has declined due to several limitations. Plant fibers can be modified in an environmentally friendly way by various methods, such as plasma therapy and treatments using fungi, enzymes and bacteria. This part provides an analysis of the impact of different environmentally friendly surface modification techniques on the properties of plant fibers and reinforced polymers. Surface treatment of natural fibers: Although plant fibers have the ability to absorb water, the majority of the work involved in creating eco-friendly goods involves altering their surface. Fungus enzyme therapy and plasma therapy have both shown potential. Plant fibers are hydrophilic, but researches have changed their surfaces to make goods that are better for the climate image

This study investigates the enhancement of mechanical characteristics of hybrid polymer composites reinforced with Palmyra Palm Leaflet (PPL) and Coconut Sheath Leaf (CSL) fibers by integrating Tamarind Shell Powder as a filler material. The composites were fabricated with varying ratios of PPL and CSL fibers, and their tensile strength, flexural strength, interlaminar shear strength (ILSS), impact strength, hardness, and water absorption were evaluated. Results indicated that the composite with 20% PPL and 10% CSL exhibited superior mechanical performance, achieving the highest tensile strength of 42.22 MPa, flexural strength of 94.35 MPa, ILSS of 7.52 MPa, and impact strength of 5.98 J. Hardness values peaked at 84.12 SD for the same composition. Moreover, the integration of Tamarind Shell Powder significantly improved the mechanical properties compared to composites without filler, which showed lower values across all parameters. Water absorption tests revealed an increase in water uptake with filler incorporation, though within acceptable limits for practical applications. Scanning Electron Microscopy (SEM) analysis further supported these results by revealing enhanced fiber-matrix bonding and better dispersion of the filler, resulting in fewer voids and defects. This research highlights the potential of bio-based fillers in optimizing the mechanical performance of hybrid composites for sustainable engineering applications.

In the present work, caustic soda (NaOH) and sodium lauryl sulphate (SLS) was used to surface-treat the plain weave cotton-kenaf with the following two primary objectives in mind: (1) to improve the strength of cotton-kenaf composites, and (2) to increase the fibre content in the composite. The cotton-kenaf composites were made with treated or untreated fibre concentrations of 25, 30, 35, and 40

The usage of jute/cotton natural composites has surged in almost all fields of engineering due to their advantage of possessing high strength to weight ratio and biodegradability. This paper deals with the fabrication and investigation of mechanical properties of jute/cotton fiber reinforced epoxy composite which is relatively a hybrid composite. In this study, the composite is fabricated by a hand layup process followed by compression molding method with varying the number of layers of composite laminates also with different cutting angles. The composites are prepared with four different proportions of jute/cotton fibers. Various mechanical tests are conducted and the result shows that the 14-layer jute/cotton composite has optimum properties achieved and also observed that 90° has better properties than the others cutting angles. Statistical analysis of composites was done by ANOVA-table; based on mean effective plots, the optimum levels of parameters have been identified, and significant contribution of parameters is determined by analysis of variance Also, failure morphology analysis is done using a scanning electron microscope (SEM) through which the internal structures of the tested specimen are analyzed.

Due to the increasing demand for environmentally safe products, the use of composites manufactured from natural fibres has become one of the most widely researched subjects lately. In this present study, the influence of weave designs on the mechanical characteristics of bio-based cotton, bamboo and cotton/bamboo fabric reinforced textile epoxy composites is presented. The textile composites were prepared by compression moulding process with different fabric weight ratio of 70:30; 65:35; 60:40; 55:45 and 50:50. The composites were tested for interlaminar shear, flexural, compressive, tensile and impact strength as per ASTM standards. Compared to other weave design composite laminates, 45 wt.% loading of cotton and bamboo textile composite achieved the greatest results for all the tests in a simple weave pattern. The scanning electron microscopy results of the fractured samples exhibited superior interfacial bonding between the fabric and matrix, as evidenced by the presence of significantly reduced fibre bend, fibre pullout, tearing and crack. The prepared natural fibre composites (cotton/bamboo) can be used as an eco-friendly alternative to man-made materials that aid in pollution management. They are also less expensive, have higher mechanical characteristics and use less energy in the manufacturing process.

Natural fibres have improved their availability in an extensive range of engineering applications at a lesser cost because of their enhanced mechanical properties. Natural fibre from coconut leaf sheath is capable of enhancing the characteristics of composite materials. In this work coconut leaf sheath strengthened with epoxy is woven into composites with different fibre weight ratios (20

The requirement of the current scenario is to identify the sustainable material and process it into acceptable properties for current applications. The natural fiber is a prime sustainable material having the properties of biodegradability, plenty of availability, economical and adequate physical-mechanical property. Sesbania rostrata fiber is extracted from the stem of Sesbania rostrata plant which is cultivated along with Turmeric plants on 1000 acres annually as a nitrogen fixation plant. The fiber-reinforced composite is a tailor made material by altering the fiber and polymer weight proportion to achieve desired properties for applications. The natural fiber is a promising material to replace synthetic fiber to transform the composite into biodegradable. The making of holes in the biocomposite by the secondary process is essential for the assembly operation. The biocomposite was developed by reinforced Sesbania rostrata fiber in Polycaprolactone (PCL) biopolymer at the weight ratio of 20:80 and the mechanical properties and drilling parameters were investigated. The tensile, flexural and impact strength of the biocomposite was increased by 68%, 28% and 20.6% respectively compared with PCL biopolymer. The biocomposite was drilled by 4 mm at spindle speeds of 300, 750, and 1800 rpm with feed rates of 0.05, 0.12, and 0.25 mm/rev to evaluate the thrust force and delamination properties. The results showed that increasing spindle speed and feed rate resulted in higher thrust force and increased delamination in the composites. This study provides valuable insights into the mechanical properties and drilling behaviour of Sesbania rostrata fiber reinforced Polycaprolactone biodegradable composite and their potential use in various applications.

The most investigated issues over the past several years have been the use of natural fibers in replacing man-made fibers. This is a result of their natural qualities, which are superior to synthetic fibers in terms of biodegradability, renewability, and abundance of availability. Since synthetic fibers are made of limited resources (fossil fuels), they are primarily impacted by changes in oil prices and their build up mostly in the environment. Even synthetic fibers replace natural fibers in terms of their mechanical and thermal characteristics. Combining these fibers/fillers as reinforcing for different polymeric composite materials provides the potential for developing structures and materials with multiple functions for leading applications. Since biological and synthetic materials individually have benefits and drawbacks, different materials have been utilized in combination and in a composite form to enhance the physicochemical, mechanical, and biological qualities.

Biocomposites developed in the past few decades have gained utmost attention amidst researchers among which natural fiber particulate and wood particle reinforced plastic composites commit toward versatile applications. Natural fiber powder reinforced plastics in the current market are commonly developed with petroleum-based polymers that pose environmental hazards on disposal. In order to develop an alternative resource for these, many attempts have been made using various bioplastics as matrix materials with wood and plant particle form reinforcements. Polylactic acid with natural fiber reinforcement has majorly resulted in providing good mechanical performance among which particulate or powdered form processed to micro- and nano-sized reinforcements exhibits outstanding mechanical properties when compared to long and short fiber reinforcements. This review consolidates previous research profiles that have worked with polylactic acid reinforced with various wood flour and plant fiber particulate combinations to provide a database for researchers working in the similar frame.

The current study focuses on the creation of epoxy composites with cotton/bamboo woven fabric reinforcement. The effect of alkali treatment with varying (1, 2, and 3 wt.%) of NaOH on mechanical characteristics such as tensile, impact, flexural, compression, and interlaminar shear stress is explored and compared to those of the untreated cotton/bamboo fabric. The composites were made using a compression moulding process with four different fibre loadings (30, 35, 40, 45, and 50 wt.%). The mechanical characteristics of the composites were studied and their structure was evaluated by using a scanning electron microscope (SEM). The cotton/bamboo/epoxy composite with 2 wt.% NaOH at 45 wt.% fibre loading was found to have better mechanical properties when compared to the others.

Natural fibre reinforced composites are being used in a variety of industries. Epoxy matrix composites reinforced with woven bamboo-cotton fibre has been fabricated via., hand lay-up technique and compression moulding technique. In the fabrication of the composite panels, the number of layers varied from 8 to 14 according to the weight of the fabric. The tensile, bending, impact, compression, water-absorption, and ILS properties for the developed composites have been tested or examined. SEM characterization was being used to examine the fractured morphology and assess interface-strength of the developed composites. It was found that increasing the number of fibre layers improved the composites' physico-mechanical properties. Due to the micro-voids, detachment, and hydrophilic nature of natural fibres, the cotton/bamboo twill fabric reinforced composites absorb the most water. In addition, the results have demonstrated that the fibre matrix debonding, which was actually the result of a weak-bonding amid the fibre and matrix, was the cause of the escalated water absorption behavior. Hence, the fabricated composites are suitable for the applications of moderate load bearing, including automobile body parts and structural components that require sufficient strength.

Machining is considered to be an important post-manufacturing process. Evaluation of machinability of natural-fiber-reinforced composites is important owing to its wide application spectrum. Current experiments focus on the drilling parameters of cotton/bamboo woven fabric reinforced epoxy composites laminates using a solid twist drill. Composites were manufactured with 45 wt.% cotton/bamboo woven fabric in epoxy resin using a compression molding method. Drilling experiments were carried out in pillar-type drilling machine and the drilling characteristics, such as thrust force, were analyzed using four process parameters like spindle speed, feed rate, drill diameter, and silane-treated fabric. Drilling experiments were carried out using the Box–Behnken Experimental Design, and the recommended drilling characteristics were analyzed using quadratic models based on response surface methodology. It was observed from the results that the thrust force is low with small drill-bit diameter, higher cutting speed, and lower feed rate, according to the response surface analysis. Surface morphology of the drilled hole suggested that a better quality of hole can be obtained at lower feed rates.