225 research outputs found

    A comprehensive review of techniques for natural fibers as reinforcement in composites::preparation, processing and characterization

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    Designing environmentally friendly materials from natural resources represents a great challenge in the last decade. However, the lack of fundamental knowledge in the processing of the raw materials to fabricate the composites structure is still a major challenge for potential applications.Natural fibers extracted from plants are receiving more attention from researchers, scientists and academics due to their use in polymer composites and also their environmentally friendly nature and sustainability. The natural fiber features depend on the preparation and processing of the fibers. Natural plant fibers are extracted either by mechanical retting, dew retting and/or water retting processes. The natural fibers characteristics could be improved by suitable chemicals and surface treatments. This survey proposes a detailed review of the different types of retting processes, chemical and surface treatments and characterization techniques for natural fibers. We summarize major findings from the literature and the treatment effects on the properties of the natural fibers are being highlighted

    Manufacturing of coir fibre-reinforced polymer composites by hot compression technique

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    This present chapter describes the manufacturing technique and properties of coir fibre-reinforced polypropylene composites manufactured using a hot press machine. The effects of basic chromium sulphate and sodium bicarbonate treatment on the physical and mechanical properties were also evaluated. Chemical treatment and fibre loading generally improved the mechanical properties. Five-hour basic chromium sulphate and sodium bicarbonate-treated coir-polypropylene had the best set of properties among all manufactured composites. Chemical treatment also improved water absorption characteristics. This proves that chemical treatment reduced the hydrophilicity of the coir fibre. Overall the hot compression technique was proved to be successful in manufacturing good quality coir reinforced polypropylene composites

    Natural Fiber-Reinforced Hybrid Composites

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    In the last few decades, natural fibers have received growing attention as an alternative to the synthetic fibers used in the reinforcement of polymeric composites, thanks to their specific properties, low price, health advantages, renewability, and recyclability. Furthermore, natural fibers have a CO2-neutral life cycle, in contrast to their synthetic counterparts. As is widely known, natural fibers also possess some drawbacks, e.g., a hydrophilic nature, low and variable mechanical properties, poor adhesion to polymeric matrices, high susceptibility to moisture absorption, low aging resistance, etc. This implies that their applications are limited to non-structural interior products. To overcome this problem, the hybridization of natural fibers with synthetic ones (i.e., glass, carbon, and basalt) or different natural fibers can be a solution. For this reason, extensive research concerning natural–synthetic and natural–natural hybrid composites has been done in the last years. In this context, this book aims to collect some interesting papers concerning the use of natural fibers together with synthetic ones with the aim of obtaining hybrid structures with good compromise between high properties (e.g., mechanical performances, thermal behavior, aging tolerance in humid or aggressive environments, and so on) and environment care

    Microstructural design of high performance natural fibre-nanoclay-cement nanocomposites

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    In this thesis, a novel approach has been used to provide beneficial insights for the development of new ‘environmental-friendly nanomaterials’, especially for building applications. This new approach includes the combination of thermal pre-treatment of nanoclay (i.e., producing calcined nanoclay) and chemical pre-treatment of natural fibre surfaces, to improve the microstructure, mechanical, physical and thermal properties, as well as the durability of hemp fibre-reinforced cement composites

    Pretreatment of Woven Jute FRP Composite and Its Use in Strengthening of Reinforced Concrete Beams in Flexure

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    Environmental awareness motivates researchers worldwide to perform studies of natural fibre reinforced polymer composites, as they come with many advantages and are primarily sustainable. The present study aims at evaluating the mechanical characteristics of natural woven jute fibre reinforced polymer (FRP) composite subjected to three different pretreatments, alkali, benzyl chloride, and lastly heat treatment. It was concluded that heat treatment is one of the most suitable treatment methods for enhancing mechanical properties of jute FRP. Durability studies on Jute FRP pertaining to some common environmental conditions were also carried out such as effect of normal water and thermal aging on the tensile strength of jute FRP followed by fire flow test. The heat treated woven jute FRP composites were subsequently used for flexural strengthening of reinforced concrete beams in full and strip wrapping configurations. The study includes the effect of flexural strengthening provided by woven jute FRP, study of different failure modes, load deflection behavior, effect on the first crack load, and ultimate flexural strength of concrete beams strengthened using woven jute FRP subjected to bending loads. The study concludes that woven jute FRP is a suitable material which can be used for flexural upgradation of reinforced concrete beams
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