Tensile Test:
The objective of this test is to estimate the ultimate strength, young’s modulus and strain to failure of the laminated composite. The samplings are made following ASTM 3039 specifications [12]. Accordingly, the specimens of 250mm*2.5mm*25mm dimension were prepared. The load-displacement curve shown in Fig 3 directly gives the final load, i.e. the load at which the specimen breaks. The ultimate load when divided by the cross-sectional area gives ultimate strength. The zone below the stress-strain curve shown in Fig 5 indicates the failure absorption energy, which is an estimate of the amount of energy the material will absorb before failure.
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It was noted that the failure of the specimen was not catastrophic. The gradual failure is evident from Fig 4. It can be observed that there is a very small initial elastic region followed by a very large plastic region. From the tensile strength plot of the different samples of jute composites given in Fig 6, it can be very well said that the tensile strength for the untreated jute fibers is not very high but with the silane treatment on it under high temperature condition, the tensile strength has increased with a significant value. Moreover, it also shows that bleaching treatment has no very effective role on enhancing the tensile …show more content…
2012.
[3] Jae Gyoung Gwon, Sun Young Lee, Geum Hyun Doh, Jung Hyeun Kim, "Characterization of Chemically Modified Wood Fibers Using FTIR Spectroscopy for Bio-composites", 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 116: 3212–3219, Feb. 2010.
[4] Jue Lu, Per Askeland, Lawrence T. Drzal, "Surface modification of micro-fibrillated cellulose for epoxy composite applications", Polymer, 49: 1285-1296, Jan. 2008.
[5] Michael A. Pinto, Vijaya B. Chalivendra, Yong K. Kim, Armand F. Lewis, "Evaluation of Surface Treatment and Fabrication Methods for Jute Fiber/Epoxy Laminar Composites", POLYM.COMPOS., 35: 310–317, Sep. 2013.
[6] Laly A. Pothan, Sabu Thomas, "Polarity parameters and dynamic mechanical behavior of chemically modified banana fiber reinforced polyester composites", Composites Science and Technology, 63: 1231–1240, Feb. 2003.
[7] M. Abdelmouleha, S. Boufia, M.N. Belgacemb, A.P. Duartec, A. Ben Salaha, A. Gandini, " Modification of cellulosic fibers with functionalized silanes: development of surface properties", International Journal of Adhesion & Adhesives, 34: 43–54, July.
Composite restoration usage in dentistry is increasing. Because of this interest in the longevity and reliability of composite fillings also is increasing1. One problem that can occur with composite restorations is micro-leakage. This is when microgaps at the tooth-restoration interface allow fluids and bacteria into the restoration2. These gaps are formed when the material is polymerized and shrinks, which causes the material to pull away from the margins of the preporation2. Problems that can arise from micro-leakage are secondary carries, hypersensitivity, pulp stimulation, and marginal discoloration3. This is why dentists are trying to find ways to reduce micro-leakage of composite restorations.
The Carbonization process used to create carbon fiber is called pyrolysis, which uses nitrogen gas and heat as a catalyst to increase the vibrational energy of atoms. The pyrolysis breaks the bonds between carbon atoms and nitrogen atoms as well as the bonds between carbon atoms and oxygen atoms. As a result, the polymer structures formed during cross-links stabilization is converted into hexagonal carbon structures. Non carbon atoms such as oxygen, and nitrogen are removed as gas through the atmosphere. The final carbon content is over 90 % after carbonization and the temperature range of carbonization is from 900 to 1600 °C in an inert atmosphere. Heat treatment, optimum tension, completion of the reactions, and keep the molecular orientation of the precursor fiber are vital variables to produce a crystalline structure aligned more perfectly and improve the tensile strength of the
Chemically all polymeric materials comprise of hydro-carbon chains and usually have high heat of combustion. When they are exposed to fire, they burn rapidly with the release of high amount of heat, flame and smoke. Similarly the natural fibers, wood flour, are highly combustible and burn rapidly. So for safely use of the composites materials they must have flame retardant properties as well.
According to author Tom Rath, the key to success is to be able to support your strengths while in the workplace and not focus so much on trying to fix your weaknesses. Strengths Finder 2.0 is assessment that argues the answer to human development is structured on what people are. After completing strength finders 2.0 online assessment you will be presented with your strengths discovery and planner guide which are formed off of your results. I myself have participated in the strength finders 2.0 assessment. The test itself was a bit entertaining because I was asked questions that I never really thought about. Mt five themes that were listed in my results was relator, focus, belief, harmony, and discipline.
rapid development of polymer chemistry after World War II a host of new synthetic fibers
A group of polymer chains can be organised together in a fiber. 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, orientated 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. Spinning is a process that involves forcing the liquefied polymer solution through a ‘die’ (small holes).
After purchasing and completing the Strength Finders self-assessment, I am now able to determine what my best strengths are in great detail. According to the results of this assessment, my greatest strengths are related to competing, focusing, strategizing, achieving, and planning for the future. When looking at my results, I fell that these strength relate well to what I believe to be my actual strengths. The first strength listed is competition. The strength of competition is believed to be that I am focused on winning. By having the strength of competition, I can clearly identify where my peers are, I can outperform them in anything that is related to competition. I personally believe that business
Fiberglass has been the most recognizable composite material, and is made up of glass fibers inlayed in a resin matrix. Fiberglass got its start when it was first used in the 1950’s for autos and boats. Today most cars have a fiberglass bumper cover that is mounted to a steel frame. Fiberglass was first used on the design of the Boeing 707 airliner in the early 1950’s. The material accounted for about two percent of the planes structure. In the 1960’s, many more composite materials were being made available, in particular graphite and boron fiber, that was then inlayed in epoxy materials. The United States Air Force and United States Navy began their own research into using these types of materials for aircraft surfaces like ailerons, rudders and flaps. The first large scale military implementation of boron fiber was in the horizonta...
The latter embraced the salts of ferrous ammonium sulphate , manganous sulphate ans cobaltous sulphate. This pre-treatment process was carried out by impregnating the cellulose thiocarbonate fabric in a single metal salt solution at 30 0C for 30 min. , as described in the metathesis procedure. The pre-metallized cellulose thiocarbonate fabric was then grafted using moderate conditions included 4% MAA , 30 mmolL SPB , at 60 0C for 60 min. The results obtained are illustrated in Figure 5a-d. The data of this figure disclose (i) that the percentages graft yield (Fig. 5a) , grafting efficiency (Fig. 5b), and total conversion (Fig. 5c) enlarge by increasing the Fe2+ salt solution concentration and attain maximal at the FAS concentration corresponds to 0.2 mmol/L ; thereafter they decrease. The homopolymer (Fig. 5d) has an adverse deportment , (ii) that all polymer criteria slightly augment by heightening the Mn2+ salt solution concentration up to 0.02 mmolL ,then fall , (iii) that the Co2+ reductant ion fails to further improve the MAA grafting efficiency and graft yield. The %TC decreases by increasing the Co2+ salt solution concentration up to 0.06 mmolL , then increases. The lone prosperity of the Co2+ ion is the enhancement of MAA homopolymer
Cellulose chains are composed of both crystalline and amorphous regions. Breaking of the amorphous portion of cellulose chain is carried out by acid hydrolysis to yield crystalline residue that is CNCs. Hydrolysis largely disintegrates the acetal linkage in amorphous part of cellulose chain while due to long exposure to acid crystalline part may also degrade (Bondeson et al., 2006). Depending on the origin of the cellulose, CNCs of different width and length have been prepared and reported by different researchers. The aspect ratio (length to width ratio) of CNCs have been observed to vary between 10 and 30 for cotton and it lies around 70 for tunicate, a sea animal (Habibi et al., 2010). CNCs of various shapes viz. rod like (Habibi et al., 2010), spherical (Wang et al., 2008) and elliptical (Lu et al., 2012) have been obtained using different acid system and different cellulose origin. Sulphuric acid is the most commonly used acid for hydrolysis of cellulose to synthesize CNCs (Kim et al., 2001; Kupiainen et al., 2012; Lalia et al., 2013; Lu et al., 2012). The presence of bisulphite ion along with H+ ions results in better cellulose hydrolysis in sulphuric acid as compared to non-sulphur acid species like formic acid (Kupiainen et al., 2012). Hydrolysis using sulphuric acid leads to the introduction of charged sulphate ester groups to the surface CNC s (Abitbol et al., 2013; Lu & Hsieh, 2010). These sulphate groups attached to the CNC surfaces results in decreasing the thermal degradation temperature of CNCs (Jiang et al., 2010). To improve the thermal stability of CNCs, hydrochloric acid has been used as hydrolysing agent for hydrolysis of cellulose (Yu et al.,
The FTIR spectrometer is a sensitive machine that utilizes light to collect an IR range of emission/absorption values of gases, liquids, or solids. When molecules absorb photons they become excited and reach a higher energy state, and alternatively when a molecule emits a photon the energy given off represents the amount of energy the molecules fall by. This technique can also be to analyze the percent ethanol present in gasoline. The OH group present in the structure of ethanol can help distinguish it from the hydrocarbons in gasoline since it absorbs at around 3500-3000 cm-1 and would form a peak within that range. Another peak of interest would be the one formed by the C-O bond in ethanol, which can be seen at approximately 1200 cm-1.
It is synthesised in plants, algae and even in some animals, and it can also be synthesised by some bacteria. Cellulose, the major chemical component of fiber wall. Cellulose has a strong tendency to form intra- and inter-molecular hydrogen bonds by the hydroxyl groups on these linear cellulose chains, which stiffen the straight chain and promote aggregation into a crystalline structure and give cellulose a multitude of partially crystalline fiber structures and morphologies. Hemicelluloses are a group of heterogeneous polymers that play a supporting role in the
It was found that in scratch resistance testing, all wood composites have lower penetration and residual depths compared to neat HDPE. Polymer composites containing untreated wood flour show less viscoelastic recovery, while composites containing modified wood flour (modified with sol-gel silica particle and/or 3-methacryloxypropyl-trimethoxysilane, MPS) gave lower value of the residual depth. The overall high scratch was found in composites, R-HDPE + 50 wt-% wood/sol-gel silica and R-HDPE + 50.0 wt-% wood/3MPS samples. The lowest friction was observed in neat polymer while highest friction was observed in wood polymer composites. Between modified and un modified wood, the friction of the composites containing modified wood showed the lowest friction compared to composites containing the neat or unmodified wood
The preparation of making wood into a pulp for papermaking is accomplished in two different ways. In the groundwood process, blocks of wood are held against a fast revolving grindstone that shreds off short wood fibbers from the block. The fibbers produced by this process are short and are used only in the production of cheap newsprint and used to be added with other types of wood fibber in the making of high-quality paper. Another technique uses a chemical-solvent processes where wood chips are treated with solvents that remove “resinous material and lignin” from the wood, leaving pure fibbers of cellulose.
present at all times but it must retain some of them. All plant life on Earth benefits from the ability of water to make a hydrogen bond with another substance of similar electronegative charge. Cellulose, the substance that makes up cell walls and paper products, is a hydrophilic substance ("water-loving"). It interacts with water but, unlike other hydrophilic substances, it will not dissolve in it. Cellulose can form strong hydrogen bonds with water molecules. This explains why a paper towel will "wick" water upwards when it comes in contact with it.