Green Polymer Composites for Aerospace Engineering Applications : A Review

The relatively high cost of man-made fibers and wire meshes used in fiber reinforced concrete and ferrocement, combined with a reduction in the usage of asbestos fibers, make it necessary to evaluate natural fibers as possible substitutes. This is particularly true in some low-cost housing applications, such as those used in Mexico, where the cost of the reinforcement represents a major portion of the total cost. Some natural fibers of the agave family, which are widely available in Mexico, show surprisingly high mechanical properties; yet little effort has been devoted so far to using them efficiently. This paper describes the results of a cooperative research project to study the use of natural agave fibers as possible reinforcement for portland cement-based matrixes. The following questions are answered: I) What are the essential mechanical properties of these fibers? 2) What are the difficulties encountered in mixing them with a mortar matrix? 3) What are the optimum and practical maximum amounts of fibers that can be mixed? 4) Can a composite showing an elasto-plastic behavior (or better) under loading accompanied by multiple cracking be obtained? 5) Does the composite have a fairly good durability under various environmental exposures? The results so far are very encouraging and necessitate further systematic research in the use of natural fibers.

The use of natural fibers as reinforcement material for natural fiber composite materials easily available, cheap, many types and variations. One of the natural fibers that can be used as reinforcement fiber composite is cantula agave plant leaves. In order to create a natural fiber composite material which has good mechanical properties, it should be known factors that affect the manufacture of the composite material. Factors that can affect the mechanical properties of the fiber composite material is fiber orientation, fiber composition, fiber volume fraction and volume fraction of the matrix. Fiber volume fraction is very large influence on the strength of the composite. This study aimed to determine the effect of fiber volume fraction on the bending strength and impact polymer composite reinforce cantula agave fiber with fiber volume fraction of 20%, 30% and 40%. The results showed that the bending and impact strength increases with increasing fiber volume fraction. Greatest bending obtained in the composite with 40% fiber volume fraction of 93.790 MPa and the lowest in the composite fiber volume fraction of 20% of 59.160 MPa, whereas for impact testing biggest impact on the composite with 40% fiber volume fraction of 0.159 Joules/mm2 and low impact strength obtained in composite fiber volume fraction of 20% amounting to 0.113 Joules/mm2

The conversion of waste into value‐added products is critical to long‐term sustainability as waste disposal costs, landfilling space, and climate change would be reduced. Research and production industries investigate the possible use of natural fibers as a substitute for fossil fuels. Natural fiber‐reinforced polymer composites’ physical and mechanical properties can be altered by natural fiber treatment, and the treatment choice relies on the desired properties and performance. In addition to cost‐profitability, environmental effects, and required performance, composites can be designed based on the product conditions. Disadvantages such as incompatibility of the hydrophilic natural fiber reinforcements with the hydrophobic polymer matrix often result in the tendency of the composite to have high moisture absorption, poor thermal stability, crystallinity, and mechanical strength. These factors critically impair the performance of the natural fibers as reinforcements in polymer composites, hence resulting in less‐favourable mechanical and physical properties. Physical, chemical, and biological treatments were examined to determine their effect on the durability and thermal, physical, and mechanical properties. It was observed that plasma treatment for bamboo fibers resulted in interfibral spaces and anchoring mechanisms between the resin and fibers, leading to increased load transfer. Chemical treatment at various concentrations improved the surface smoothness. The best mechanical, physical, thermal, and chemical properties for application as reinforcement in polymer composites were obtained at 6% for alkali treatments. Enzymatic treatment showed a significant impact on the impact and flexural strength of the composites. Factors such as duration, concentration, and extent of treatment need to be established for effective treatment, as prolonged treatments may damage the NFs’ properties. This review comprehensively highlights the potential utilization of current natural fiber treatment methods for the potential of natural fibers as value‐added products for construction materials, considering their economical affordability, production of lightweight materials, sustainability, utilization of readily available waste material, and nature preservation. Furthermore, the three natural fiber treatment approaches for improving fiber‐matrix adhesion are discussed. The physical and mechanical properties of composites are highlighted, which aids in evaluating suitability for construction materials.

A Review on mechanical property of sisal glass fiber reinforced polymer composites

Fiber reinforced polymer composites (FRPCs), due to their multifunctional properties, have already occupied a significant place in various applications such as aerospace, automotive, marine, structural engineering, and healthcare industries. Lightweight FRPCs are preferred over heavier materials because of some key advantages, such as high strength-to-weight ratio, corrosion resistance, design flexibility, fatigue resistance, damping properties, and electrical and thermal insulation properties. Though synthetic fibers such as carbon, glass, aramid fiber reinforced composites are found to provide better performance, these fibers are expensive as well as impose adverse impacts on the environment. Currently, bast fiber reinforced biocomposites (BFBCs) are receiving increasing attention due to their biodegradability, availability, low cost, and higher strength-to-weight ratio. Researchers are working rigorously on BFBCs to unveil their optimal properties. BFBCs can be disposed of easily without affecting the environment. BFBCs, with their sustainable and biodegradable properties, notably promote the use of natural fibers particularly bast fibers and minimize the consumption of expensive and non-degradable synthetic fibers reinforcements in the composite industry. This paper provides an overview of the use of different natural fibers in reinforcing polymer composites for various applications to achieve sustainability. The influence of various fibrous preforms of bast fibers on the mechanical behavior of BFBCs, and their prospects are comprehensively reviewed.

During the past few years, the use of technical textiles has grown rapidly. Natural, synthetic, and high-performance fibers are being used in many technical textile applications. Some of which are explained in detail, while others are in brief in this book. This chapter reviews the application and use of natural, synthetic, and high-performance fibers for Indutech, Hometech, Clothtech, Buildtech, Packtech, and Oekotech. As the strength of natural fibers is not so good, the use of synthetic and high-performance fibers is increasing in industrial and technical products. One of the major applications of technical textiles is in the filtration media. The performance of a specific filter is based on the selection of fiber, textile material, and the way they have been assembled. The properties of fluid for which the filter has to be designed must be considered carefully as well. Human beings have been using regular clothing to protect themselves from a very hot and cold environment. The workers in some occupations (like military, police, firefighting, and healthcare) are exposed to different hazards, so they are required to wear protecting textile clothing, which is discussed further in the chapter. For centuries, textiles are being used for construction materials whether it is for insulation or reinforcement of any other application. However, the use of advanced construction material specifically textile fibers has increased extensively these days. It is important to have appropriate knowledge about textile fibers in the light of current climate change and other global challenges, as textiles in any form (fiber, yarn, or fabric) provide excellent thermal and mechanical properties with low weight. Today the people around the world have become more educated with higher living standards. Therefore, the use of high technology products, which offer enhanced performance, durability, hygienic conditions, and aesthetic, has become the need of the day. The demand for eco-friendly and bio-degradable packaging is growing now as they have a great impact on human health and the environment. The use of natural fibers for environmental protection is not new. While the use of synthetic and high-performance fibers for environmental protection is a revolutionary change in the current century. One of its uses is in protecting the crops and soil artificially by weather changes to increase productivity. The new and advanced developments for environmental protection keep on increasing across the world in the coming years. In this chapter, an overview of such types of textiles; fibers being used; and their applications, advantages, and drawbacks have been provided briefly.

An empirical research on areca fiber polymer composite for automotive components in modern industry

In recent years, interest in using natural fibers in a number of applications especially in biocomposites has grown because they are eco-friendly, lightweight, combustible, nontoxic, low cost and easy to recycle. On the other hand, the lack of good interfacial adhesion and poor resistance to moisture absorption and chemicals make the use of natural fibers less attractive. Chemical treatment of the lignocellulosic fiber can stop the moisture absorption process, clean the fiber surface, chemically modify the surface or increase the surface roughness. Silane treatment of natural fibers is a promising process for improving physical and chemical properties of fibers. The work presented in this article gives insight into the effect of silane treatment on physical and chemical properties of Pinus fibers. Further polymer composites were prepared using urea-formaldehyde as a novel polymer matrix resin. The silane-treated and untreated fibers along with polymer composites have been characterized by various techniques such as scanning electron microscopy (SEM), Fourier transform-infrared spectrophotometry (FT-IR) and thermogravimetric/differential thermal analysis along with DTG studies. Composites prepared were also subjected to the evaluation of different mechanical, physical, and chemical properties.

The study of a new designed table tennis racket for training strike accuracy

Use of natural fiber as reinforcing material is the latest invention of polymer science in order to get higher strength with lower weight composite materials having several applications. In this present investigation banana fiber, a natural fiber, is used as the reinforcing material. Low density polyethylene (LDPE)-banana fiber reinforced composites were prepared using both untreated and bleached (treated) banana fiber and LDPE with 7.5, 15, 22.5 and 30% weight content of fibers by using compression molding technique. Physico-mechanical properties (e.g. tensile strength, flexural strength, elongation at break, Young's modulus) of different types of prepared composites were characterized. From this study it is observed that all these values have augmented up to a definite percentage. The tensile strengths and flexural strengths of the composites increased up to 22.5% fiber addition then started to decrease gradually. Young moduli of the composites increased with the increase of fiber addition. Water absorption also increased with the weight of the fiber. Whereas elongation at break decreased with increasing fiber loading. Mechanical properties of bleached banana fiber-LDPE composites were slightly higher than the untreated banana fiber-LDPE composites. Compared to virgin molded LDPE both tensile and flexural strengths and Young moduli of these LDPE-banana fiber composites were significantly higher. All the variable properties like tensile strength, flexural strength, and water absorption capacity showed a very significant role in these polymer composites. Keywords: Banana fiber; LDPE; Composite; Tensile strength; Flexural strength DOI: 10.3329/bjsir.v45i2.5708Bangladesh J. Sci. Ind. Res. 45(2), 117-122, 2010

Green Composites From Sustainable Cellulose Nanofibrils

Natural fibers are being used in composites as a means of environmental protection through the use of biodegradable components. By combining natural and synthetic fibers, the use of natural fibers might be expanded significantly, potentially lowering the cost of hybrid composites. Fiber reinforced polymer-based composites have been used in a wide range of industrial applications for a very long time because of their high specific strength and modulus. The use of coir, a natural fiber, as reinforcement in reinforced polymers was decided upon due to the availability of different natural fibers. Natural fibers are equally as strong and light as they are affordable. Therefore, the aim of this research is to analyze the mechanical characteristics of a jute fiber/polyester hybrid composite filled with eggshell. In this study, woven jute fibers and polyester filled with eggshell powder were employed to construct composites utilizing the layering technique. In accordance with ASTM standards, tensile, flexural, impact, and water absorption tests are performed to assess the influence of ratio. Five ratios were employed: 80% eggshell powder and 20% polyester (EP80P20), 70% eggshell powder and 30% polyester (EP70P30), 50% eggshell powder and 50% polyester (EP50P50), 40% eggshell powder and 60% polyester (EP40P60), and 20% eggshell powder and 80% polyester (EP20P80). The results show that the composite with EP20P80 has the highest tensile strength, elasticity and flexural strength, followed by EP40P60, EP50P50, EP70P30 and EP80P20. This implies the increment ratio of the eggshell powder leads to the reduction in tensile strength, elasticity and flexural strength. Meanwhile, the statistical data analysis shows that there are a significant difference among the five ratios (p-value < 0.05) for the tensile and flexural tests. However, the impact test shows the opposite result.

Interest in natural fibres as reinforcement in developing countries arose (when the use of steel and glass fibres in the industrialized countries was being researched and developed in the late 1960s) mostly because of their lower cost and better availability in the developing world. The use of natural fibres as reinforcement for mortar to be used mainly for roofing has been debated for a long time. Initially, it was rightly thought that natural fibres will adversely affect the setting of Portland cement and as such they should not be used. Later on it was found that natural fibres are embrittled by the hydration products of Portland cement and made ineffective within a short time, especially in hot climates. While such discussions were going on, the initially adopted large corrugated roofing sheet (corrugated iron sheet size) was being found impractical (mainly because of handling and curing problems) and its size was being reduced gradually. The present paper discusses difficulties encountered in the production and use of natural fibre reinforced mortar roofing tiles and means of reducing the adverse effects of Portland cement hydration products on the performance of natural fibres in mortar.

Due to environment and sustainability regulation in the last decades considerable performance in green technology in the field of materials science through the development of biocomposites could be noticed. Thus, the development of high-performance materials produced from natural resources expands worldwide. This can be attributed mainly due to their assets compared to their synthetic contourparts like low cost, low weight, less damage to processing equipment, improved surface finish of moulded parts composite, good mechanical properties, biodegradability, abundant and renewable resources. Natural fibres are valuable and versatile resources with multiple advantages.Nowadays all the more, the automotive industry is under increasing pressure to fulfill environmental and performance demands and higher fuel efficiency at competitive costs. Automakers recognize potential in biocomposites if these materials can offer the same performance as traditional composites but with lower weight. Additional they exhibit non-brittle fracture on impact, which is another significant requirement for automotive sector. Other drivers that scores for use of natural fibres reinforced polymer composites (NFRPC) in automotive applications imply reduced waste disposal, reduction of greenhouse gas emission and Life Cycle Consideration.In spite of their benefits, the significant challenge for producers and supplier to handle with natural fiber reinforced polymer composites resides in large inconsistency of their properties. The chemical composition of vegetal fibres relies on several factors comprising fiber variety, time of harvesting, climatic history, soil characteristics and fibre processing technology. All these factors exert an influence on their final properties when used as reinforcements in biocomposite materials.In this review a wide range of issues is addressed with special reference to mechanical properties of fibres, interface adhesion and environmental implication of NFRPC. The discussion on the cellulosic/lignocellulosic fibre properties is conducted in order to relate their chemical composition, microstructure and mechanical properties and to understand their use and limits as reinforcements in composite materials.The variation within the mechanical properties of natural fibres is a challenge towards designing predictable components for industry since the engineers are accustomed to the precise and reproducible properties of synthetic fibres.The hydrophilic nature of lignocellulosic fibres causes poor resistance to moisture and incompatibility to hydrophobic polymer matrix. As a consequence, this incompatibility causes a weak fibre/matrix interface, which consecutively leads to diminished mechanical properties of the biocomposites. Therefore, it is important to ensure a good adhesion between matrix and fibres to enhance the mechanical strength of NFRPC.This study aims to provide an overview of the greener surface treatments without use of hazardous chemicals, with emphasize on the enzymatic surface modification of natural fibres. The effectiveness of the treatment on the mechanical properties of the resulting NFRPC is also reviewed.Environmental impact of NFRPC is another important issue addressed in this review. A comparison of the environmental impacts between the NFRPC and SFRPC applied in the automobile sector, based on LCA studies, will be traced.

Processing and characterization of natural cellulose fibers/thermoset polymer composites