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Fiber reinforced composites are made by reinforcing fibers in a polymeric matrix and shaping them to fit. Natural fibers, on the other hand, such as jute sisal, hemp, flax etc. are increasingly commonly utilized as reinforcements and perform similarly to artificial fibers. Man‐made fibers like as carbon, glass, and kevlar are utilized as reinforcements in the start and have shown to be the best in terms of characteristics, reinforcing capacity, and usefulness. Research investigations also show that when man‐made and natural reinforcements are combined in a hybrid form, the composite characteristics increase significantly. The composite material obtains all of the better qualities of individual fibers as a result of this combination, and when the composite is subjected to varying loads, each fiber gives its own maximal resistance. The chemical and physical properties are further enhanced by including particular reinforcements into polymer matrix composites, which provide whole new features (which has transformed the aerospace, marine, defence, and automobile industry). As a result, the composite would be better in all attributes. The current study provides a thorough examination of the different challenges concerning the synthesis and mechanical characterization of natural fiber reinforces hybrid polymer composites. Future difficulties, as well as areas of use for polymer matrix composites, have been investigated that may aid in the elimination of plastic waste and the reduction of environmental pollution. [ABSTRACT FROM AUTHOR]

This study is devoted to characterization of the Glycyrrhiza glabra (licorice root) fibers (GGFs) that have different uses in industrial areas, globally. For this purpose, several properties of GGFs were investigated to determine their suitability for natural fiber-reinforced composite production. Such properties include; physical, chemical, thermal, morphological, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy, as well. As a result of these analyses, it was found that the GGFs are composed of cellulose (40.46%), hemicellulose (15.94%), lignin (12%), waxes (1.3%), moisture (9.93%), and others. The density of GGFs was measured as 1.43 g/cm3. Additionally, the existence of cellulose with a 35.86% crystal index, was also verified by the XRD characterization results of these fibers. The thermogravimetric analysis (TGA) results showed that GGFs are thermally stable within the polymerization process temperature of 354.09°C. As a result, it was determined that GGFs have characteristics with significant potential as cellulose-based reinforcement fiber for industrial applications. [ABSTRACT FROM AUTHOR]

Natural cellulose fibers have a great potential for the development of new alternative reinforcement materials that are used in various polymer composite applications. In this study, waru tree trunk fiber was extracted and treated with NaOH and Silane. Meanwhile, the characteristics of chemical, morphological, mechanical, and fiber surfaces were determined through composition analysis, Fourier transforms infrared (FTIR), scanning electron microscope (SEM), and single fiber test. The results showed that the cellulose content increased with the addition of silane treatment which was supported by the high crystalline index of 63.02% waru bark fiber. Based on this treatment, the tensile strength of the single fiber had the highest value of 243.94 Mpa. Therefore, this fiber has the potential as a new reinforcement development in polymer-based products.

Improvement in mechanical properties of the natural fiber reinforcement for potential use in the composite for mechanical performance is a key focus of researchers in recent years. However, few studies are available in the literature on the mechanical performance of hybrid-woven fabrics. In this article, the effect of the weave structure of reinforcing fabric on mechanical performance has been investigated. Jute-based woven fabrics having four different weave structures (matt, sateen, and hybrid-weave A/B) were developed in the in-house lab using a shuttle dobby weaving machine. The tensile test and puncture tests were performed to evaluate the mechanical performance by varying the weave architecture. The sateen weave exhibited maximum penetration load during a puncture test. The results demonstrated a significant improvement in the tensile strength by using a hybrid weave in the warp direction. However, sateen woven fabric demonstrated enhancement in the tensile attributes in the weft-wise direction. Similarly, a hybrid weave consisting of a combination of sateen and matt weave exhibited a maximum stiffness value. To check the statistical significance of the results, ANOVA analysis was performed. The findings of ANOVA suggest that the results are statistically significant. This research will open a new avenue in the field of reinforcement composite material.

Improvement in mechanical properties of the natural fiber reinforcement for potential use in the composite for mechanical performance is a key focus of researchers in recent years. However, few studies are available in the literature on the mechanical performance of hybrid-woven fabrics. In this article, the effect of the weave structure of reinforcing fabric on mechanical performance has been investigated. Jute-based woven fabrics having four different weave structures (matt, sateen, and hybrid-weave A/B) were developed in the in-house lab using a shuttle dobby weaving machine. The tensile test and puncture tests were performed to evaluate the mechanical performance by varying the weave architecture. The sateen weave exhibited maximum penetration load during a puncture test. The results demonstrated a significant improvement in the tensile strength by using a hybrid weave in the warp direction. However, sateen woven fabric demonstrated enhancement in the tensile attributes in the weft-wise direction. Similarly, a hybrid weave consisting of a combination of sateen and matt weave exhibited a maximum stiffness value. To check the statistical significance of the results, ANOVA analysis was performed. The findings of ANOVA suggest that the results are statistically significant. This research will open a new avenue in the field of reinforcement composite material. [ABSTRACT FROM AUTHOR]

Natural cellulose fibers have a great potential for the development of new alternative reinforcement materials that are used in various polymer composite applications. In this study, waru tree trunk fiber was extracted and treated with NaOH and Silane. Meanwhile, the characteristics of chemical, morphological, mechanical, and fiber surfaces were determined through composition analysis, Fourier transforms infrared (FTIR), scanning electron microscope (SEM), and single fiber test. The results showed that the cellulose content increased with the addition of silane treatment which was supported by the high crystalline index of 63.02% waru bark fiber. Based on this treatment, the tensile strength of the single fiber had the highest value of 243.94 Mpa. Therefore, this fiber has the potential as a new reinforcement development in polymer-based products. [ABSTRACT FROM AUTHOR]

Biological materials that are created by growing mycelium-forming fungal microorganisms on natural fibers can form a solution to environmental pollution and scarcity of natural resources. Recent studies on the hybridization of mycelium materials with glass improved fire performance; however, the effect of inorganic particles on growth performance and mechanical properties was not previously investigated. Yet, due to the wide variety of reinforcement particles, mycelium nanocomposites can potentially be designed for specific functions and applications, such as fire resistance and mechanical improvement. The objectives of this paper are to first determine whether mycelium materials reinforced with montmorillonite nanoclay can be produced given its inorganic nature, and then to study the influence of these nanoparticles on material properties. Nanoclay-mycelium materials are evaluated in terms of morphological, chemical, and mechanical properties. The first steps are taken in unravelling challenges that exist in combining myco-fabrication with nanomaterials. Results indicate that nanoclay causes a decreased growth rate, although the clay particles are able to penetrate into the fibers' cell-wall structure. The FTIR study demonstrates that T. versicolor has more difficulty accessing and decaying the hemicellulose and lignin when the amount of nanoclay increases. Moreover, the addition of nanoclay results in low mechanical properties. While nanoclay enhances the properties of polymer composites, the hybridization with mycelium composites was not successful. [ABSTRACT FROM AUTHOR]

Replacing weaving and stitching used in textile-based reinforcements by using short fibers as a binder was discussed based on the tensile and compressive properties of [0], [± 45], and [0/90] laminates. A slight decrease in the longitudinal properties of the [0] composites was accompanied by a significant reduction of the properties of variability. In the case of [± 45] laminates, the presence of the short flax fiber shows a positive effect on the tensile, shear, and compressive properties. The mechanical properties of [0/90] laminates have shown a limited effect of the short fibers, with a slight decrease of both modulus and strength.

This paper presents a novel natural fiber reinforcement manufacturing approach, based on a combination of short flax fibers and unidirectional flax yarns inspired by a papermaking process. The short fibers are used as a binder, replacing weaving and stitching used in textile-based reinforcements. The tensile and compressive properties of three different composites, in both longitudinal and transverse directions, were studied in order to highlight the effect of the mat binder. The presence of short fibers in the composite resulted in a slight decrease of about 10% of the longitudinal tensile modulus and strength. However, the transverse tensile properties are almost doubled. A similar trend was obtained in compression loading, where the addition of short fibers decreases the compressive modulus and strength. Particularly, the compressive strength in the yarn direction was more influenced by the presence of short fibers and was reduced by 30% compared to a decrease of 10% in the case of tensile loading. Here again, the transverse modulus was slightly increased, even if no effect was observed on the transverse compressive strength. The presence of the short fibers also shows a significant positive effect on the fracture behavior in tensile loading. The fractured surface is more uniform and presents a reduction of the splitting and crack formation along the unidirectional yarn direction.

Biological materials that are created by growing mycelium-forming fungal microorganisms on natural fibers can form a solution to environmental pollution and scarcity of natural resources. Recent studies on the hybridization of mycelium materials with glass improved fire performance; however, the effect of inorganic particles on growth performance and mechanical properties was not previously investigated. Yet, due to the wide variety of reinforcement particles, mycelium nanocomposites can potentially be designed for specific functions and applications, such as fire resistance and mechanical improvement. The objectives of this paper are to first determine whether mycelium materials reinforced with montmorillonite nanoclay can be produced given its inorganic nature, and then to study the influence of these nanoparticles on material properties. Nanoclay–mycelium materials are evaluated in terms of morphological, chemical, and mechanical properties. The first steps are taken in unravelling challenges that exist in combining myco-fabrication with nanomaterials. Results indicate that nanoclay causes a decreased growth rate, although the clay particles are able to penetrate into the fibers’ cell-wall structure. The FTIR study demonstrates that T. versicolor has more difficulty accessing and decaying the hemicellulose and lignin when the amount of nanoclay increases. Moreover, the addition of nanoclay results in low mechanical properties. While nanoclay enhances the properties of polymer composites, the hybridization with mycelium composites was not successful.

Thermoplastic polyurethane (TPU) reinforced with natural or renewable fillers gained significant attention in the scientific community and industries. The properties of TPU can be tailored using different reinforcements or blends to enhance its performance and elevate the potential applications of the composite. Besides, composites offer eco-friendliness, recyclability, and biocompatibility thus overcoming the environmental concerns. However, the manufacturing in mass quantity and upholding the quality of these composites has remained one of the principal challenges. Herein, we critically highlighted an overview of the current comprehension of the various eco-friendly and renewable fillers/fibers reinforced in TPU composites for tuning the mechanical and thermal properties of TPU. Some of the important research articles that discuss the influence of interactions, morphology, and modification/treatment of fillers are contained within to understand the behavior and consequence of reinforcements on the physical properties of TPU composites. [ABSTRACT FROM AUTHOR]

Replacing weaving and stitching used in textile-based reinforcements by using short fibers as a binder was discussed based on the tensile and compressive properties of [0], [± 45], and [0/90] laminates. A slight decrease in the longitudinal properties of the [0] composites was accompanied by a significant reduction of the properties of variability. In the case of [± 45] laminates, the presence of the short flax fiber shows a positive effect on the tensile, shear, and compressive properties. The mechanical properties of [0/90] laminates have shown a limited effect of the short fibers, with a slight decrease of both modulus and strength. [ABSTRACT FROM AUTHOR]

This paper presents a novel natural fiber reinforcement manufacturing approach, based on a combination of short flax fibers and unidirectional flax yarns inspired by a papermaking process. The short fibers are used as a binder, replacing weaving and stitching used in textile-based reinforcements. The tensile and compressive properties of three different composites, in both longitudinal and transverse directions, were studied in order to highlight the effect of the mat binder. The presence of short fibers in the composite resulted in a slight decrease of about 10% of the longitudinal tensile modulus and strength. However, the transverse tensile properties are almost doubled. A similar trend was obtained in compression loading, where the addition of short fibers decreases the compressive modulus and strength. Particularly, the compressive strength in the yarn direction was more influenced by the presence of short fibers and was reduced by 30% compared to a decrease of 10% in the case of tensile loading. Here again, the transverse modulus was slightly increased, even if no effect was observed on the transverse compressive strength. The presence of the short fibers also shows a significant positive effect on the fracture behavior in tensile loading. The fractured surface is more uniform and presents a reduction of the splitting and crack formation along the unidirectional yarn direction. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • PP/sugarcane bagasse composites were prepared from agricultural waste. • Sugarcane bagasse fibers reinforce polypropylene similarly to other natural fibers. • Debonding dominates when adhesion is weak, while fracture occurs when it is strong. • Increased plastic deformation results in slightly improved impact resistance. Abstract Polypropylene composites were prepared from sugarcane bagasse fibers by extrusion and injection molding. Wood flour was used as reference filler in the study. The fiber content of the composites changed between 0 and 30 wt% in 5 wt% steps. Maleated polypropylene was used as coupling agent to improve interfacial adhesion. Mechanical properties were characterized by tensile and fracture testing, while local deformation processes were followed by acoustic emission and instrumented impact testing, as well as by the analysis of scanning electron micrographs. The results showed that sugarcane bagasse fibers reinforce polypropylene similarly to other natural fibers. They increases stiffness, but decrease tensile yield stress, tensile strength and deformability. Increased interfacial adhesion leads to the considerable improvement of reinforcement. Bagasse fiber and wood flour filled composites have very similar properties. The impact resistance of the composites increased in the presence of both fibers compared to the neat matrix. Debonding is the dominating process in the absence of the coupling agent, while mainly fiber fracture occurs in its presence. Increased plastic deformation after debonding results in slightly improved impact resistance. [ABSTRACT FROM AUTHOR]

The current work deals with three dimensionally molded plywood formed parts. These are prepared in two different geometries using cut-outs and relief cuts in the areas of the highest deformation. Moreover, the effect of flax fiber reinforcement on the occurrence and position of cracks, delamination, maximum load capacity, and on the modulus of elasticity is studied. The results show that designs with cut-outs are to be preferred when molding complex geometries and that flax fiber reinforcement is a promising way of increasing load capacity and stiffness of plywood formed parts by respectively 76 and 38% on average.

To improve the interfacial bonding of sisal fiber-reinforced polylactide biocomposites, polylactide (PLA) and sisal fibers (SF) were melt-blended to fabricate bio-based composites via in situ reactive interfacial compatibilization with addition of a commercial grade epoxy-functionalized oligomer Joncryl ADR@-4368 (ADR). The FTIR (Fourier Transform infrared spectroscopy) analysis and SEM (scanning electron microscope) characterization demonstrated that the PLA molecular chain was bonded to the fiber surface and the epoxy-functionalized oligomer played a hinge-like role between the sisal fibers and the PLA matrix, which resulted in improved interfacial adhesion between the fibers and the PLA matrix. The interfacial reaction and microstructures of composites were further investigated by thermal and rheological analyses, which indicated that the mobility of the PLA molecular chain in composites was restricted because of the introduction of the ADR oligomer, which in turn reflected the improved interfacial interaction between SF and the PLA matrix. These results were further justified with the calculation of activation energies of glass transition relaxation (ΔEa) by dynamic mechanical analysis. The mechanical properties of PLA/SF composites were simultaneously reinforced and toughened with the addition of ADR oligomer. The interfacial interaction and structure--properties relationship of the composites are the key points of this study. [ABSTRACT FROM AUTHOR]

Hydrogels which become increasingly important in the biomedical field are composed of a three-dimensional hydrophilic network. Pure hydrogels are usually weak and brittle; therefore, reinforcements are assimilated into the hydrogel structure to improve the mechanical strength of the hydrogels. However, even if mechanical properties are enhanced, drapability remains an issue. In that regard, natural fiber-reinforced composite hydrogel fibers for wound dressing application are investigated in this study. Kapok and hemp fibers were used as reinforcement to improve the strength of hydrogel fibers. The properties of the prepared composite hydrogel fibers were studied with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimeter (DSC). The effect of alginate concentration and fiber weight percent on the mechanical characteristics and water absorbency was studied. Diclofenac sodium drug was loaded in the hydrogel fibers and investigated the drug release as well as antibacterial characteristics. Both fibers' reinforcement enhanced the strength of the alginate hydrogel fiber, but hemp reinforcement showed better mechanical properties. Kapok reinforcement resulted in a maximum tensile strength of 174 cN (1.24 % elongation) and 432 % exudate absorbency, while hemp reinforcement resulted in 185 cN (1.48 % elongation) and 435 % exudate absorbency. Statistical analysis revealed significant effects of sodium alginate concentration on tensile strength (p -value 0.042) and exudate absorbency (p-value 0.020) and of reinforcement (wt%) on exudate absorbency (p-value 0.043). Therefore, these composite hydrogel fibers with improved mechanical properties are capable of drug release and exhibit antibacterial effectiveness, making them a promising option for use as wound dressings. [ABSTRACT FROM AUTHOR]

Since the starting the 21st century, there is an increased awareness that non-renewable resources are becoming scarce, and dependence on renewable resources is growing. The 21st century may be the cellulosic century as we look more and more to renewable plant resources for products. It is easy to say that natural fibers are renewable and sustainable. Although the use of these materials is not new, horse hair was used in mortar and straw for mud bricks, and many plants types like sisal, coir, bamboo, jute, akwara, elephant grass…etc. In this papers, a human hair fibers (HHF) is studied as a reinforced material in cementitious material. A total of 86 concrete specimens (Cubes, cylinders, prisms and plates) are tested to study the effect of including human hair fibers HHF reinforcement on the mechanical properties of flowable mortar fiber reinforced concrete. Fibers of different lengths and equivalent diameters were used with an aspect ratio ranged from 500 to 700, fiber content ranges from zero to 1 percent by volume. The influence of fiber content on the compressive strength, splitting tensile strength, flexural strength and load deflection is presented for two w/c ratios (0.6 and 0.7). An improvement in the energy absorption capacity due to the fiber addition is observed, and the optimum fiber volume fracture is seen to be 0.8%. The experimental findings in our tested samples will encourage future researches in this direction for long term performance to extending this cheap type of fibers for use in structural applications especially for low strength cementitious materials.

To improve the interfacial bonding of sisal fiber-reinforced polylactide biocomposites, polylactide (PLA) and sisal fibers (SF) were melt-blended to fabricate bio-based composites via in situ reactive interfacial compatibilization with addition of a commercial grade epoxy-functionalized oligomer Joncryl ADR@-4368 (ADR). The FTIR (Fourier Transform infrared spectroscopy) analysis and SEM (scanning electron microscope) characterization demonstrated that the PLA molecular chain was bonded to the fiber surface and the epoxy-functionalized oligomer played a hinge-like role between the sisal fibers and the PLA matrix, which resulted in improved interfacial adhesion between the fibers and the PLA matrix. The interfacial reaction and microstructures of composites were further investigated by thermal and rheological analyses, which indicated that the mobility of the PLA molecular chain in composites was restricted because of the introduction of the ADR oligomer, which in turn reflected the improved interfacial interaction between SF and the PLA matrix. These results were further justified with the calculation of activation energies of glass transition relaxation (∆Ea) by dynamic mechanical analysis. The mechanical properties of PLA/SF composites were simultaneously reinforced and toughened with the addition of ADR oligomer. The interfacial interaction and structure–properties relationship of the composites are the key points of this study.

With the growing popularity of hybrid yarn techniques, the micro-braided yarn is becoming a good choice as one kind of intermediate materials for thermoplastic biocomposites, by presenting favorable morphology during the preform process and lowering the resin flow distance during the thermo-compression process. In this article, different flax/polypropylene (PP) based multi-core micro-braided hybrid yarns with the similar total number of flax core fibers were manufactured, by varying the parameters: multi-core configuration and braiding angle; both dry-and thermo- states tensile tests on yarns were carried out, since it is necessary to simulate the deforming behavior of a single hybrid yarn during the thermoforming process. The objective is to determine the cover factor especially for multi-core micro-braided yarn as a comprehensive textile indicator; and to study the influence of the cover factor parameters on mechanical tensile properties at the yarn scale. It has been observed that the cover factor parameters contributed the braider effect (friction and compression) on flax cores in the dry-state and lubricant effect (distribution and viscosity) in the thermo-state; further influenced the characterizations. Increasing multi-core configuration and braiding angle can both increase the tensile strength; larger cover factor results in greater tensile stiffness both in dry-and thermo-states. [ABSTRACT FROM AUTHOR]

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The current work deals with three dimensionally molded plywood formed parts. These are prepared in two different geometries using cut-outs and relief cuts in the areas of the highest deformation. Moreover, the effect of flax fiber reinforcement on the occurrence and position of cracks, delamination, maximum load capacity, and on the modulus of elasticity is studied. The results show that designs with cut-outs are to be preferred when molding complex geometries and that flax fiber reinforcement is a promising way of increasing load capacity and stiffness of plywood formed parts by respectively 76 and 38% on average. [ABSTRACT FROM AUTHOR]

• Lightweight geopolymer blocks were produced for non-structural construction purposes. • Compressive strength in the block was 8.1 MPa and bulk density was reduced to 1269 kg/m3. • Hydrogen peroxide proved to be effective for reducing density in geopolymer matrices. • Fine aggregate positively affected strength and dimensional stability of geopolymer mortars. • Stabilization of geopolymer mortars with jute fibers was necessary to control cracking. • The fibers were also effective for controlling the non-brittle failure of the blocks. Lightweight geopolymers are alternative low-carbon footprint building materials with high potential to produce value added products for the construction industry such as low-density masonry units. This work focuses on presenting the development of a new lightweight masonry block using natural pozzolana-based geopolymer mortar, hydrogen peroxide as a foaming agent and jute fibers as reinforcement additive. The experimental plan allowed the optimization of the production process and the definition of the optimum quantities of hydrogen peroxide content, pozzolana: fine aggregate ratios and the appropriate amount of fibers to be incorporated. The experimental results demonstrate the feasibility of the production of new masonry units, which can achieve up to 8.1 MPa of compressive strength after 28 days of fabrication with reduced bulk densities of 1269 kg/m3. [ABSTRACT FROM AUTHOR]