Fiber Reinforced Polymer Composites Pdf Free

Fiber-reinforced plastic (FRP), also known as fiber-reinforced polymer, reinforced plastics/composites, or fiberglass, is a composite material made of a polymer matrix reinforced with fibers. The polymer is usually an epoxy, vinyl ester, phenolic resin or polyester thermosetting plastic. The fibers are usually glass, carbon or aramid. In some processes, resin products are fabricated without fibers, such as synthetic marble. Fiber-reinforced plastics products have a wide range of application in industry, transportation, home, and recreation. Generally, the manufacturing of these FRP products has the potential to emit air pollutant emissions of volatile organic compounds (VOCs), Hazardous Air Pollutants (HAPs), and in some case, Particulate Matter (PM).

Fibre-reinforced plastic (FRP; also called fibre-reinforced polymer, or in American English fiber) is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually glass (in fibreglass), carbon (in carbon-fibre-reinforced polymer), aramid, or basalt. Rarely, other fibres such as paper, wood, boron, or asbestos have been used. The polymer is usually an epoxy, vinyl ester, or polyester thermosetting plastic, though phenol formaldehyde resins are still in use.

A polymer is generally manufactured by step-growth polymerization or addition polymerization. When combined with various agents to enhance or in any way alter the material properties of polymers, the result is referred to as a plastic. Composite plastics refers to those types of plastics that result from bonding two or more homogeneous materials with different material properties to derive a final product with certain desired material and mechanical properties. Fibre-reinforced plastics are a category of composite plastics that specifically use fibre materials to mechanically enhance the strength and elasticity of plastics.

Bakelite was the first fibre-reinforced plastic. Leo Baekeland had originally set out to find a replacement for shellac (made from the excretion of lac bugs). Chemists had begun to recognize that many natural resins and fibres were polymers, and Baekeland investigated the reactions of phenol and formaldehyde. He first produced a soluble phenol-formaldehyde shellac called "Novolak" that never became a market success, then turned to developing a binder for asbestos which, at that time, was moulded with rubber. By controlling the pressure and temperature applied to phenol and formaldehyde, he found in 1905 he could produce his dreamed-of hard mouldable material (the world's first synthetic plastic): bakelite.[3][4] He announced his invention at a meeting of the American Chemical Society on 5 February 1909.[5]

Global polymer production on the scale present today began in the mid 20th century, when low material and productions costs, new production technologies and new product categories combined to make polymer production economical. The industry finally matured in the late 1970s when world polymer production surpassed that of steel, making polymers the ubiquitous material that they are today. Fibre-reinforced plastics have been a significant aspect of this industry from the beginning.

FRP allows the alignment of the glass fibres of thermoplastics to suit specific design programs. Specifying the orientation of reinforcing fibres can increase the strength and resistance to deformation of the polymer. Glass reinforced polymers are strongest and most resistive to deforming forces when the polymers fibres are parallel to the force being exerted, and are weakest when the fibres are perpendicular. Thus, this ability is at once both an advantage or a limitation depending on the context of use. Weak spots of perpendicular fibres can be used for natural hinges and connections, but can also lead to material failure when production processes fail to properly orient the fibres parallel to expected forces. When forces are exerted perpendicular to the orientation of fibres, the strength and elasticity of the polymer is less than the matrix alone. In cast resin components made of glass reinforced polymers such as UP and EP, the orientation of fibres can be oriented in two-dimensional and three-dimensional weaves. This means that when forces are possibly perpendicular to one orientation, they are parallel to another orientation; this eliminates the potential for weak spots in the polymer.

Fibre-reinforced plastics are best suited for any design program that demands weight savings, precision engineering, definite tolerances, and the simplification of parts in both production and operation. A moulded polymer product is cheaper, faster, and easier to manufacture than a cast aluminium or steel product, and maintains similar and sometimes better tolerances and material strengths.

As a subset of plastic, FR plastics are liable to a number of the issues and concerns in plastic waste disposal and recycling. Plastics pose a particular challenge in recycling because they are derived from polymers and monomers that often cannot be separated and returned to their virgin states. For this reason not all plastics can be recycled for re-use, in fact some estimates claim only 20% to 30% of plastics can be recycled at all. Fibre-reinforced plastics and their matrices share these disposal and environmental concerns. Investigation of safe disposal methods has led to two main variations involving the application of intense heat: in one binding agents are burned off - in the process recapturing some of the sunk material cost in the form of heat - and incombustible elements captured by filtration; in the other the incombustible material is burned in a cement kiln, the fibres becoming an integral part of the resulting cast material.[26] In addition to concerns regarding safe disposal, the fact that the fibres themselves are difficult to remove from the matrix and preserve for re-use means FRP's amplify these challenges. FRP's are inherently difficult to separate into base materials, that is into fibre and matrix, and the matrix is difficult to separate into usable plastics, polymers, and monomers. These are all concerns for environmentally-informed design today. Plastics do often offer savings in energy and economic savings in comparison to other materials. In addition, with the advent of new more environmentally friendly matrices such as bioplastics and UV-degradable plastics, FRP will gain environmental sensitivity.[1]

According to Gay, Hoa, and Tsai [9], aerospace structures use a core made of aluminum or Nomex honeycomb. Birman and Kardomateas [10] suggested that civil engineering requires the use of a closed-cell or open-cell foam, while ship sandwich structures require the use of balsa. Therefore, these combinations of material have resulted in a competitive structure in various application areas, such as aerospace, transportation, marine, and civil structures, where high strength, low weight materials, and fuel economy are essential factors; as well as impact mechanics and high-energy absorbing materials. A comprehensive study of energy absorption and crashworthiness was published by Carruthers et al. [11]. This review demonstrated that fiber reinforced plastics can be designed to exhibit higher normalized energy absorption capabilities than the metals that have been traditionally used for vehicle construction. Alghamdi [12] reviewed research on the common shapes of collapsible energy absorbers, such as circular and square tubes, frusta, struts, honeycombs, and sandwich plates. A study on impact mechanics and high energy absorbing structures and materials, as well as new concepts for design structures, such as the high energy absorbing properties of lattices structure, was published by Qiao et al. [13]. Chai and Zhu [14] reviewed the low-velocity impact of sandwich structures. The mechanical response of composite sandwich structures with tubular inserts to quasi-static compression was studied by Tarlochan et al. [15]. As noted by Zuhri et al. [16], sandwich structures can be seen in natural fiber structures such as bamboo and grass.

From the aforementioned statements, NFCs have been suggested to substitute for the previous traditional composites, including glass, basalt, carbon, and aramid fiber composites [32]. This could be happening due to the NFCs themselves, which have low manufacturing costs, with higher productivity, as well as good mechanical strength and stiffness. Generally, the performance of NFCs depends on the fiber type. For instance, bast fibers tend to show superior flexural strength, while leaf fibers tend to offer excellent impact properties [33]. Thus, the understanding of natural fiber properties and forms is crucial for achieving successful improvement outcomes [34,35,36,37]. Chandrasekar et al. [38] found that flax fiber reinforced epoxy composites exhibited higher bending and impact strengths. Of equal importance, an accurate aspect ratio should be considered, because natural fibers can exist in different forms, such as entangled yarn, bundles, and elementary fiber [39]. There are various factors that influence the mechanical performances of a natural fiber, e.g., fiber content, temperature, humidity, fiber treatment, and fiber type.

The hybridization of NFCs to improve their mechanical properties has become an area of interest to researchers in recent times. For instance, Alavudeen et al. [113] presented a study on the mechanical properties of kenaf/banana hybrid composites. It was shown that the kenaf/banana composites offered better mechanical properties compared to the individual fiber-based composites. In a similar study by Venkatesh et al. [114], the addition of bamboo fiber to sisal-unsaturated polyester composites enhanced their mechanical properties compared to the sisal-unsaturated polyester composites on their own. Moreover, Wu et al. [115] hybridized silk fiber with flax fiber, and studied their mechanical properties. The study showed that the hybrid exhibited improved flexural strength and impact strength over other NFCs. In addition, an examination of the mechanical properties of sisal and banana fiber-reinforced polylactide acid (PLA) composite was carried out by Gupta et al. [116]. According to their study, the treated fibers gave better mechanical properties than pure PLA and untreated fiber bio-composites. 2b1af7f3a8