Haydar U Zaman et al. [31] studied the effect of fibre incorporation on the tensile modulus of the composite. The tensile modulus of virgin PP was found to be 478MPa which increased with increased fibre loading. Tensile modulus was found high in treated composite than in untreated one. The tensile modulus of CF/PP composite at 40% CF was about 1577.1 MPa. ACF/PP showed about 21% higher tensile modulus than CF/PP composite. ASCF/PP composite showed about 28% improvement in tensile modulus on comparing with other composites. S. H. P. Bettini et al. [35] investigates the use of coir fibre as alternative reinforcement in polypropylene. Tensile strength and elongation at break decrease during the incorporation of coir fibre. Tensile strength increased …show more content…
[41] investigated the tensile behaviour of short coir fibre reinforced Poly (Butylene Succinate). It was found that tensile modulus of PBS increased with the incorporation of coir fibre since the stress was transferred from matrix to the stiffer fibre. The tensile modulus of composite increased with increase in fibre weight content. Coir/PBS composite with 5 different fibre content showed an improved of 17.9%, 40.3%, 61.9%, 84.4% and 106.6% on comparing with pure PBS. Tensile strength and fracture strain decreased with increase in fibre content. At 10% fibre loading the fracture strain reduced by 65% compared to PBS matrix. The ductile nature of PBS decreased with fibre addition. With the increase in fibre loading, the percentage of fracture strain decreased with fibre loading, which increased the tensile modulus. Incorporation of fibre increased fibre agglomeration and led to the formation of stress concentrated region, less energy was needed for elongating the crack propagation. Tran Huu Nam et al. [42] investigated the effect of the tensile property of coir fibre reinforced poly (Lactic acid) biodegradable composite. It was noted that tensile strength increased up to 20% fibre content but decreased with higher fibre …show more content…
[43] studied the tensile properties of green coconut fibre reinforced HDPE polymer composite. It was found that tensile strength was found higher at 40% fibre content compared to 30% and 50%. It was noted that tensile strength decreased with increase in fibre length. The tensile strength of the composite depends on the fibre length. For 30% fibre loading the tensile strength was found to be 3.90MPa and at 40% fibre loading the tensile strength was 17.37MPa. Tensile strength was found maximum at a fibre length of 3mm; this was due to the increased interfacial bond between fibre and matrix. Tensile strength was found the minimum for a fibre length of
Some ceramics are used in orthopaedic applications such as bone repair, bone augmentation and joint replacement but their use in this field is not as extensive or widespread as metals and polymers because ceramics have poor fracture toughness. This severely limits the use of ceramics in load bearing applications (Davis, 2003).
Laird DF, Mucalo MR, Dias GJ. Vacuum‐assisted infiltration of chitosan or polycaprolactone as a structural reinforcement for sintered cancellous bovine bone graft. Journal of Biomedical Materials Research Part A. 2012;100(10):2581-92.
Kevlar is made up of carbon fibers and shares the same characteristics as other aromatic polyamide. Kevlar has distinctive trait and chemical shape that makes it special from other human made fibers. Kevlar is made up of mixture of pure strength, high resistance, hardness, and heat stability. Nylon and polyester became available for human production of fibers in the late 20th century. They used to trim the fiber at its edge back in their time, but they need to reach a maximum of strength and an initial value. In order for that to achieve, the Kevlar molecules should have an extended set of figures and almost supreme clear order. With these bendable molecules such as nylon, this can only be made by mechanically pulled after the rotation process.
The brittle failure is due to high contact stresses at the cutting edge due to a combination of critical cutting parameters. The weak cutting edge du to the crate also contributes to the brittle failure.
How the polymer chains are put together is important, as it improves the properties of the material. The flexibility, strength and stiffness of Kevlar fiber, is dependent on the orientation of the polymer chains. Kevlar fiber is an arrangement of molecules, oriented parallel to each other. This orderly, untangled arrangement of molecules is described as a “Crystalline Structure”. A manufacturing process known as ‘Spinning’ is needed to achieve this crystallinity structure.
Denture teeth can be made of acrylic poly(methyl methacrylate) (PMMA) or composite resins. PMMA is a polymer - a material made the from joining of methyl methacrylate monomers. Properties of PMMA include resistance to abrasion, chemical stability and a high boiling point. (Jun Shen et al. 2011). However, weak flexure and impact strength of PMMA are of concern as they account for denture failure. (Bolayir G, Boztug A and Soygun K. 2013). Composite denture teeth are made of a three distinct phases - filler, matrix and coupling agents. Out of the types of composite teeth available, nano-filled composite teeth are preferred. Composite teeth have a PMMA coating around the tooth and a high content of filler particles. This gives them strength, higher resistance to forces than acrylic teeth and provides compete polymerization due to the PMMA coating. (Anusavice, K. J., Phillips, R. W., Shen, C., & Rawls, H. R, 2012). If the interface between the PMMA denture base and PMMA or composite teeth was weak, the denture will not be able to sustain occlusal forces, making the base-teeth interface, an entity of significance.
Major aerospace engineering bodies such as NASA soon realised the importance of this technology and scientists began to develop carbon fibre composites for use in aircraft and spacecraft. Currently, carbon fibre composites are some of the most widely used materials in the aerospace and aviation industry as one of strongest materials available, being five times the strength of steel. It is also a third of the weight of steel and therefore incredibly lightweight. A composite is defined as a material consisting of two or more individual constituents. These composites are made from carbon fibre fabric (the fibres woven together) which is permeated with epoxy resin at temperatures of around 125 degrees. The product is a carbon fiber sheet. This can then be shaped into a pattern and finally bonded with a structural adhesive7. The use of CFC’s is most prominent in modern military aircraft, where most external components such as wings, doors and rear fuselage sections are partially made using them. The aim of using this material is to reduce weig...
The successful use of wood-based particles and fibers as fillers or reinforcements in thermoplastic composites requires an essential considerate of the structural and chemical personalities of wood [1]. English and Falk give an inclusive overview of the factors that influence the properties of wood–plastic composites [2]. While several studies have revealed that fiber-polymer compatibility can be improved by selecting appropriate coupling agents [3,4], compatibility between polar wood fiber and non-polar thermoplastics remains key to extend the function limits of the resulting composites [5]. Another repeatedly cited key factor in natural fiber thermoplastic composites is thermal degradation [6]. In addition, different wood species have different anatomical structures. These structural differences direct the use of these materials in WPC. For instance, fiber dimensions, strength, unpredictability, and structure are important consideration. Maldas et al. have investigated the result of wood species on the mechanical properties of wood/thermoplastic composites [7]. They reported that differences in morphology, density, and aspect ratios across wood species account for varying strengthening properties in thermoplastic composites. Recently, Neagu et al. investigated the stiffness part of various wood fibers to composite materials. They observed a connection between lignin content and longitudinal Young’s modulus, and an optimal lignin content range for maximum fiber stiffness was recorded for softwood Kraft fibers [8]. Several efforts have been practiced to link wood-based particles and fiber properties to WPC properties [9–11]. A high aspect ratio (length/width) is very essential in fiber strengthened composites, as it indicates pote...
chains instead of hydrogen atoms. Cross-linking is another way in which the polymer can be made stronger. This involves ultraviolet radiation that bombards the polymer with electrons and formulates bonds between the molecular chains of the polymers. This is like linear polyethylene but different in that it is more impact resistant, and it has a much higher density. This allows it to be stored or be used with different chemicals that would normally cause the polymer to desolve.3 This can start to become a problem because as the polymer continues to become chemically enhanced. So the ways of dissolving and recycling the polymer become more difficult.
Carbon-fiber-reinforced-polymer (CFRP) is a composite polymer made up of carbon fibers and a binding polymer. The binding polymer can be a thermoset resin or thermoplastic polymer(s). Examples of thermoplastic polymers that can bind with carbon fiber to make CFRP are polyester, nylon, or vinyl ester. A thermoset resin that can combine with the carbon fiber to make CFRP is epoxy. The combination of the carbon fibers and a thermoset resin or thermoplastic polymer producing CFRP results in a light weight fiber-reinforced plastic that is tremendously strong. Depending on the binding polymer, CFPRs have a wide range of applications and are used when a light weight material with high rigidity and strength are required.
The applications of natural fibers in composite are also spreading widely in many sectors such as automobiles, packing ,construction furniture and sports. This is mainly due to the advantages of natural fibre over synthetic such as low cost, low density, less damage to processing equipment, good relative mechanical properties, renewablility, biodegradability. Natural fibers were also introduced with the intention of reducing wieght of composites, showing a tendency to replace the existing glass fiber reinforced polymer composites .
F. L. Matthews and R. D. Rawlings, Composite Materials: Engineering and Science, 1 edition. Woodhead Publishing, 1999.
Matus M. (9, April 2012). Super-Durable Material Made from Wood Waste is Stronger, Cheaper, and Lighter Than Kevlar. Retrieved May 27, 2014, from Inhabitat: http://inhabitat.com/super-durable-material-made-from-wood-waste-is-stronger-cheaper-and-lighter-than-kevlar/
Composite materials can have specific mechanical properties to perform a specific task. For example, we can adjust the wear resistance, toughness, thermal and so on
At the meantime, the push-out technique is considered as a valuable and useful method for evaluating these goals (23). Various factors are involved in the flexural strength of composites. Reducing the size of the filler material followed by increasing the amount of filler material in the composites lead to an increase in the flexural strength of the composite due to better inter-composite stress transfer and improved mechanical properties of the composite (24-26). In addition, the type of filling material is also effective on flexural strength and the high-strength filling material increases the flexural strength of the composite