Interfacial Bonding Characteristics in Natural Fiber Reinforced Polymer Composites

Interfacial bonding of natural fiber reinforced composites is important to be in contact with reinforcement and matrix at the time of processing of a composite which brings in to close bonding. The strength of the composites will be more if the Interfacial bonding is high. Variety of materials, chemical treatment, and pre-processing before making composites which increases the interfacial bonding between the natural fiber matrix. The selection of a proper binder for the suitable fiber along with the ideal pre-processing technique is the key determining factor of the interfacial bonding technique. So, in this chapter, various specifications of fiber and matrix bonding are discussed and analyzed with the interfacial bonding using SEM image.

In recent years, because of rising environmental consciousness, depletion and emission issues of oil resources arose several research and production attempts to use natural fibres instead of synthetic fibres in fibre reinforced composites. Natural fibres can be a sustainable resource for composites with several advantages such as being biodegradable, cheap and available, having acceptable strength to weight ratio, low density, excellent insulating/noise absorption and reduced tool wear. Researchers increasingly explore and try to find novel and appropriate methods to utilize natural fibres in various industrial applications. However, plant based fibres have some drawbacks due to especially its chemical structure. When compared to its synthetic competitors like glass fibres, natural fibres have poor moisture/water resistance that causes swelling, poor fibre/matrix adhesion, low impact resistance, low durability, restricted maximum processing temperature, poor fire resistance, and quality variability. Among those disadvantages, it is fundamental to resolve problems of fibre-matrix interactions to produce a qualitative composite that meets certain specifications. Several researches revealed that improving the interfacial interactions in natural fibre-matrix composites by establishing better stress transfer results better physical, mechanical and thermal performance. Therefore, modifying the natural fibre surface through several methods in order to improve adhesion of fibre and matrix for successful utilization of these materials in different applications. This chapter provides a review of existing research that points out surface modification or treatment methods of natural fibres and underlines recent methodologies established improving interfacial interactions between natural fibres and matric for composite applications.

Technological advances in recent years have required the improvement of materials with advanced features and multifunctionality in order to satisfy the requirements for different applications. Therefore, a growing interest is observed in the use of composite materials, especially polymeric matrices, because of the versatility that these materials exhibit.

The ideal substitute materials for plastic to address the issues of pollution and non-biodegradability are natural fibre reinforced composites. These are non-toxic, biodegradable, less expensive, and have potential applications in a variety of industries, including packaging, furniture, and home goods. This is because natural fibres are abundant in nature, biodegradable, and inexpensive. However, due to inadequate interaction/bonding between hydrophilic natural fibre and hydrophobic thermoplastic/thermoset matrix, its competency with thermoplastic is hampered by low mechanical qualities and other physical features. Numerous studies have been conducted with the goal of strengthening the chemical interaction between the fibre and matrix, either by roughening the surface of natural fibre or by altering resin. Spectroscopic examination, including Fourier transform infrared, Raman spectroscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy are used to characterize the produced composites after modification of natural fiber. The strength of the composites in question is provided by the connection between functional groups of fibre and resin at the interface, which was discovered through spectral analysis of composites.

Natural fibers are widely used owing to their vicinity friendly. Amongst all the natural fibers, the utilization of kenaf is more beneficial because of its huge availability, less cost, withstanding ability for adverse climatic conditions, and fast growth. In the case of considering the kenaf fiber’s capability of mechanical strength which depends on the matrix material like all other natural fibers. Herein, the focus is on given the interfacial bonding of the kenaf fiber at various combinations. The secondary consideration is given the tensile characteristics of kenaf fiber-reinforced composites.

It is the aim of this piece of research to investigate Pineapple fiber reinforced composites based on natural fibers that are both eco-friendly and possess unique properties, and to take into account their various properties and their eco-friendliness. As a result of their strength, lightness, and affordability, pineapple fibre materials are considered to be stronger, lighter, and more affordable than traditional materials due to the fact that they are stronger, lighter, and more affordable than natural materials. It has been an important research subject for scientists in recent years to investigate the use of natural fibres as reinforcement materials for polymeric composites that can be used in technical applications. There are many advantages of natural fibers, such as continuous supply, easy handling, and a biodegradable nature, which make them a good choice when it comes to textiles. Due to its low cost, low density, hardness, better tolerance for harsh weather conditions, and good performance thermally and mechanically, natural fibres have gained a great deal of popularity worldwide because of their low cost, low density, hardness, and environmental friendliness. A large number of crops are produced every year around the world, and most of the waste produced by these crops does not have any use whatsoever. It is estimated that thousands of tons of different crops are produced every year. As it is well known, agricultural wastes include leaves from pineapples, dates seeds, and shells from various types of dry fruits, as well as other organic wastes. As part of this project, we have combined the wastes from pineapple leaves (PALF) into a single product. There are numerous promising applications for metal, such as the use of metal as an alternative to the construction of automobile bodies in the future, which are currently being investigated.

Natural fiber-based composite materials have emerged applications in automotive, aerospace, and marine applications. For better mobility, light and strong material requirement led to the development new composites for automobiles and the aerospace industry. This study deals with different composite plates made of different layers of natural fiber (Jute) and resin (epoxy and hardener). The mechanical properties, such as the impact strength of the composites, were studied by introducing different fiber orientations. This chapter reported on gaining data from impact strength and wire mesh reinforcement. The impact strength variations for Charpy and Izod test methods were observed for 30, 40, 50, and 60% fiber volume fractions. The results show that the 60% addition of jute fiber loading improves impact strength by 175%. The impact strength of 45° oriented wire composite specimen depicts better interfacial bonding between the jute fiber and wire mesh than 90° oriented wire mesh composite.

The use of composites continue to grow thanks to low cost processing, ecofriendly and design flexibility mainly when natural fillers are used as reinforcement. These later are widely used as reinforcement for polymers due to environmental concerns as well as for providing high performance. An interphase is created between the two constituents and will have the role of transmitting the constraints from one to the other, hence the establishment of good adhesion. The interfacial adhesion is very important to improve the properties of composites. In this chapter, the use of cotton fibers as composites in the strengthening phase will be reported. Next, the different treatment methods used to improve the interfacial bonding between the fiber and the matrix and its impact on the dynamic mechanical properties of cotton fiber reinforced composites will be debated.

This chapter reviewed the influence of interfacial bonding characteristics of bamboo fiber on the composites’ mechanical, physical, thermal, and fire performance. Because of their complete biodegradability and renewability, being economical, non-toxic, non-abrasive and environmentally friendly, having high aspect ratio, socio-economical advantage and strong mechanical performances, bamboo fibers are considered promising reinforcements for polymer composites. As an alternative to petroleum-based or synthetic materials, bamboo also has the potential to be used in biopolymer composites, which can be utilized as construction, building, architectural and other advanced materials. However, strong and substantial interfacial bonding of the bamboo fibers with the polymer matrix is required to create high-end load bearing composites. Therefore, it is critical to achieve a good fiber-matrix interaction, resulting in lesser voids and better adhesion and mechanical properties. Thus, most bamboo fibers are treated, hybridized, laminated, and coupled using chemical agents to enhance the fiber-matrix bonding, which in turn enhances the performance. The detailed understanding of the aspects of fiber-matrix interaction and their respective influences on the various properties of the bamboo composites are given in this chapter, along with the superiority of the bamboo fibers in being used as the polymer reinforcement.

Flax fibers are mainly oriented to their use in handicrafts, furniture, decorations, carpets. However, in recent years, these fibers have been directed towards other industrialized sectors such as automotive, construction, military, and transportation due to their high rigidity and resistance. Flax fiber is often used as a reinforcing phase in thermoplastic composites and, to a lesser extent, as a natural reinforcement in thermosetting resins. In this way, composite materials reinforced with flax fiber are in the spotlight for developing new products and boosting other markets, complying with environmental regulations, and reusing abundant waste at a low cost. However, natural fibers have specific weaknesses, such as their hygroscopic nature and low resistance to fire, and flax fiber is no exception. Additionally, the intrinsic nature of the constituents of the composites (linen fiber and polymer resins) are generally incompatible, so the interfacial bonding is fundamental to looking for optimal mechanical performance and its behavior against fire, essential for its use and commercial application. Optimizing the interface between the natural reinforcement and the polymeric matrix is perhaps the most critical aspect in developing polymeric composites reinforced with flax fibers. Natural fibers are flammable and therefore add to the flammability of composites in which the organic matrix is also volatile. This book chapter presents an overview of the effect of interfacial bond compatibility between components of natural fiber-reinforced composites, including surface treatments intended to improve compatibility and strategies to increase the fire resistance of flax fibers.

Neoteric years have seen aaggregatedintrigue in the sphere of natural fibre composites (NFCs) as promising dossier for electrical appositenessdue to their exiguous cost, lightweight, and renewable nature. NFCs offer several ascendancy over immemorial materials, to the same degree asceramic oxides, metals, and synthetic polymers, including ameliorated sustainability, biodegradability, and curtail the environmental impact. NFCs can be engineered to exhibit multifarious electrical attributes, including electrical conductivity, dielectric properties, surface resistivity, volume resistivity and electromagnetic interference (EMI) shielding. Manifold natural fibers like cotton, flax, hemp, jute, wool, silk and sisal have been investigated for their electrical attributes. These fibers can be bestowed in amalgamation with multifarious matrix materials, to the same degree as thermoplastics, thermosets, and biopolymers, to produce NFCs with tailored electrical and mechanical properties. To obtain an optimum electro-mechanical hallmark attributes of the NFCs a tenacious interfacial bonding (IFB) betwixt the matrix and the fibers are required for tight bonding which allows for efficient transfer of charges betwixt the two phases. IFB personates a crucial role in promoting the bonding betwixt the fibers and matrix by limiting the gaps or bereft regions (voids) in the interfacial terminal region that can impede the transfer of electrical charges, resulting in lower electrical conductivity of the composite. To embroider the electrical attributes of NFCs, disparate approaches have been scrutinized, including the accession of conductive fillers or additives, to the same degree as carbon forms (graphene layers and nanotubes),metal nano (in disparate %) particles, and the embodiment of coupling operators to promote interfacial bonding betwixt the natural fibers and matrix. Vast research on the role (execution) of IFB in arbitrating the mechanical attributes of the NFCs are available, but significantly exiguous research was conducted on studying the repercussion of IFB on the electrical attributes of NFCs are reported. This offshoot chapter focuses on the repercussion of IFBs on electrical attributes of NFCs, factors affecting the electrical attributes of NFCs, tests to find out the electrical attributes of NFCs and the approaches to convalesce the IFB to facilitate optimum electrical attributes are presented.

The ever-depleting situation of petroleum resources and stringent environmental norms have encouraged the usage of natural fibres in composites as a reinforcement material. But due to less availability of natural plant fibres, there is minimal demand for natural fibres from the commercial point of view. This is because of the inferior physical properties of natural fibres due to their staple length, and poor compatibility due to hydrophilic natural fibre and hydrophobic matrix. Also, the material properties of natural fibres reinforced polymer matrix composites (NFRPMC) such as mechanical performance, thermal degradation properties, and durability are inferior. There are fewer applications of natural fibres reinforced composites as there is high demand for synthetic fibres reinforced composites. But currently, natural fibres and their derivatives-based composites have adored foremost success through research & development and also commercially it has gained humungous success in several macro to nanoscale application areas. Natural fibre persists, has a better stiffness-to-weight ratio, and bio-degradability, sustainable in nature and economical in comparison to synthetic fibres. This chapter summarizes the future challenges of natural fibre-reinforced composites. The key challenges that the NFRPMC face are majorly due to inferior material properties of the natural fibres, issues with composite processing techniques, thermal degradation, issues with composite performance, composite durability, lack of product diversification and lastly due to the recycling, biodegradability and circular economy issues. Therefore, in this chapter, we have discussed the current trend in the research of NFRPMC and their future potential and challenges for product diversification has been analysed.

Bio-composite materials, which are formed of natural fibers and a polymer matrix, represent an engineering composite product that can be beneficial for a diverse range of uses. These materials are being used in an ever-expanding variety of applications because of the extraordinary qualities they possess, the varied designs they come in, and the appealing ways they may be put to use. Nevertheless, the application of these bio-composites is reliant on the interface bonding between fiber and matrix internal bonding in order to achieve the desired level of performance. The interfacial connection that exists between the fiber and the matrix has a considerable impact on the physicomechanical characteristics of the bio-composites. Numerous researchers have been motivated to investigate natural fibers’ potential applications in a broad selection of industrial sectors as a consequence of the fact that natural fibers are readily accessible, inexpensive, and biodegradable. There are several drawbacks associated with these fibers, including the fact that they have an extreme moisture absorption degree, which causes to an increase in the thickness swelling, they are simple to degrade, they have a low resistance to fire, they have heterogeneity in their mechanical characteristics and that they have poor interface bonding with the polymer matrix. With the intention of enhance the bonding among fiber-matrix adhesion and, by extension the physicomechanical properties of the composites, a number of chemical modifications are implemented. This chapter offers a comprehensive review of the chemical treatments and uses for a broad range of natural fiber-reinforced composites that are currently available.

In this work, the vibrational behavior of luffa cylindrica/USP composites has been addressed. The effect of fiber dosage with difference fiber content from 30, 40, 50% and chemical treatment (NaOH) are analyzed. The specimens are fabricated with compression molding technique with pressure of 17 MPa. For the production of composite specimens, untreated and NaOH treated fiber were used as reinforcement and unsaturated polyester resin (USP) used as matrix. The prepared specimens are cut as per the ASTM standard, and mechanical and vibrational tests were conducted. The experiential nodal analysis is used to fine the natural frequency and damping of the composites. The results depicts that the increase in fiber dosage started to improve the mechanical properties of the composite beam. The NaOH treatment showed the improvement in mechanical and damping of the composites. The 50% fiber dosage showed the good tensile and flexural properties of the composites. The interfacial mechanism of the composites was interpreted in the SEM.