Effect of thermalaging and chemicaltreatment on the physical properties of coirfiber was investigated. Coir fibers were treated with sodium hydro- xide and glutaraldehyde for 2 h. The influence of alkali and aldehyde treatment on tensile strength and elongation at break was studied in detail. Enhancement in tensile strength of coirfiber was observed up to five days of aging at 50°C and further decreased. Thermal cross linking of cellulose present in the fiber may be the reason for the increase in tensile strength and thermal degradation due to the chain scission of cellulose reduced the tensile strength. Sodium-hydroxide-treated samples showed an increase in tensile strength and reduction in elongation at break. The removal of impurities such as waxy and fatty acid residues from the coirfiber by reacting with strong base solution improved the strength of fiber. Cross linking of cellulose with glutaraldehyde in the fiber reduced the elasticity and enhances the strength of the material. Scanning electron microscopy was employed to analyze the change in surface morphology upon chemicaltreatment. Improvement in the tensile strength suggests that NaOH and glutaraldehyde can be effectively used to modify coirfiber with excellent physical properties.
The Young’s modulus of raw treated coirfiber increased with increase in span length, while the tensile strength and strain to failure of the same decreased with increase in span length. The surface of raw coirfiber was a bit rough and porous; while the surface of double stage chemical treated coirfiber was found compact and smoother. Chemicaltreatment improves the tensileproperties of coirfiber. Double stage chemicaltreatment showed better properties compared to the single stage chemicaltreatment. During single stage treatment basic CrSO4 reacts with fiber cellulose, so a thin layer formed on fiber surface which make it smooth and compact. In double stage treatment after 3 hours treatment with basic CrSO4 again NaHCO3 is added and another reaction takes place during 2 hours shaking. Here two chemical agents basic (CrSO4 again NaHCO3) react with the fiber cellulose, so that a thick and smoother layer is formed on fiber surface. Clearly it can say that both treatments improve the surface morphology but the double stage treatment provides the better then single stage treatment. However, both treatments improve the chemical bonding of coirfiber which results good mechanical properties then the raw fiber. In these two treatments the shaking time is very important to improve the reaction rate. Shaking provides the full reaction of fiber with chemical reagent and cleans the fiber surface.
Based on observations on the micro picture as in Figure 4, it is clear that the fiber does not experience brownish colored alkali treatment of suspected elements of the bond between the micro fibers that make up into a single fiber and the other components are attached to the fiber surface. This result is believed to be the fibertensile strength is higher than the fiber experienced alkali treatment because micro fiber that make up a single fiber can simultaneously hold a tensile load is received. While fiber is being subjected to alkaline appear brighter that causes the binding component between micro fibers to be reduced. As a result, the tensile strength of the fiber will decrease due to the tensile load received is not distributed evenly throughout the micro fibers that make up a single fiber.
Compared to raw fibers, the improved strength was observed to be around 47.9% to 5% of NaOH. The maximum tensile strength was reported at 5% NaOH treatment. The improvement in the tensile strength of raw fiber compares to that with 5% NaOH treated fibers exceeded 237.43 ± 104.82Mpa. The increase in tensile strength is associated with the decrease in fiber diameter because of the loss of hemicellulose in the fibers due to alkali treatment, as shown in Table 2. Furthermore, under alkali treatment with 5% NaOH, the percentage of cellulose content in the fiber increases to produce high tensile strength of the fibers. The tensile strength of raw and treated CHFs were higher than that of fiberglass (tensile strength of fiberglass =1.7–3.5 Mpa; Pothan et al., 2005) 20 .
Abstract. Application of composite materials as a alternative materials is developed, The most of composite material is polymer matrix composite (PMC), with the polymer as a matrix and the sintetic fiber such as fiberglass and fiber carbon as a reinforced, it can make a materials with intermediete mechanical properties such as strength, hardness and thoughness, between matrix and fiber. Since the synthetic fiber was dangerous for human, so recenly developing natural fiber composite with advantages of natural fiber is more environmentally friendly, and more cheap than synthetic fiber. Otherwise, natural fiber has stong enough when it use at interior automotive parts, such as dashboard. Some cars already use the natural fiber for the interior parts. The natural fiber has a big potential, especially pineapple in Indonesia, the pineapple production at East Kalimantan is 25 344 tonnes in 2014. It means a lot of leaves can be used for the natural fiber. Pineapple leaf fiber (Pineapple Leaf Fiber / PALF) has a pretty good tensile strength of 126 MPa, and Young modulus of 4405 MPa and has a cellulose content About a 70-80% cellulose, cellulose which has a crystalline structure, so it can be good reinforced for composite. The result of this experiment, the optimum value of tensile strength is 29.9648 MPa , at composite PALF – Alcalinitation 40%.
carbon–carbon covalent bond with the matrix and in addition combines with hydroxyl groups of the fiber thus providing effi- cient interlocking. Maleic anhydride reacts with PP chain forming maleic anhydride grafted Polypropylene (MAH-PP). Then hot MAH-PP is made to react with cellulose fibers pro- viding covalent bonds across the interface. This copolymer is first heated to 173 ° C and then esterification occurs with cellu- lose fiber. The surface energy of fiber and the matrix becomes on par with each other and thus provides superior drenching and adhesion between fiber and matrix. Coupling agents also reduce fiber fractures and contribute to increased tensile strength (Agung et al., 2012). The reaction of anhydride of coupling agent with the hydroxyl groups of fibers reduced the compatibility problems between the fiber and matrix (Maya and Anandjiwala, 2008). Fiber matrix adhesion enhanced owing to the use of coupling agent which led to ester- ification between MAH-PP and hydroxyl groups of cellulose fibers (Bledzki et al., 2007). Mohanty et al. showed that sisal fiber composites with MAH-PP coupling agent had 50% higher tensile strength (Mohanty et al., 2004).
applications where mechanical performance and structural durability are of major importance.Enhua Yang and Victor (2013) have investigated the rate dependence of ECC and explore the underlying micromechanical sources responsible for the rate effect. It provides knowledge for ECC re- engineering. Several preliminary attempts have been made to redesign a new generation of ECC for high rate applications and following results are achieved. The tensileproperties of PVA-ECC M45 exhibit strong rate dependence. The tensile strain capacity decreases from 3% to 0.5% when the loading rate increases from quasi-static to seismic strain rate. The interfacial chemical bond strength, of M45 shows a strong rate dependence which contributes to the composite rate dependency. Extreme ductility of ECC under higher loading rate could be retained, if properly designed. At seismic loading rate, the tensile strain capacity is 3.2% for ECC with PE fiber, 1.5% for PVA-ECC M45 with 8mm fiber, and 3.5% for lightweight ECC with a light-weight matrix. This research demonstrates that ECC can be engineered with high ductility suitable for high rate loading applications. Mustafa Sahmaran and Victor (2010) have found out the benefits of ECC including high ductility and very tight crack width under applied loads. Regarding the transport properties the finely distributed micro cracks provide good resistance to transport of water or aggressive substance from the environment. The risk of water transport by permeability and capillary suction, and chloride transport by diffusion in ECC, cracked or uncracked, is found to be comparable with or lower than the normal sound concrete without any cracks. The paper suggests that the ECC strain hardens after first cracking, as do ductile metals, and it demonstrates the strain capacity 300 to 500 times greater than the normal concrete. Apart from unique tensileproperties, durable properties and transport facilities, ECC offers frost resistance with and without deicing salts, performance in hot and humid environment, performance in high alkaline environment, self–healing and spall resistance. The research results indicate that because of intrinsic self – control tight crack width, robust self-healing performance, and high tensile strain capacity, many durability challenges confronting concrete can be overcome using ECC.
Mir et al.  performed surface treatment on coirfiber, after that a systematic investigation on the mechanical and physical properties of coir-polypropylene bio composites had conducted. For improving the compatibility with polypropylene matrix, the coirfiber was reacted with basic chromium sulfate and sodium bicarbonate salt in acidic solution. Composites with fiber percentage of 10, 15 and 20 were prepared. The study reveals that the chemically treated fiber based composite showed good mechanical charecters than untreated. The composite with 20% fiber weight concentration exhibited optimum mechanical property compared to other. During surface treatment, the OH groups of untreated coir cellulose which were hydrophilic in nature had been changed to hydrophobic –OH-Cr groups. Because of this, the water absorption amount of composite was also lowered. Reddy et al.  treated glass/bamboo hybrid fiber reinforced polyester composites with some chemicals such as sodium carbonates, sodium hydroxide, acetic acid, benzene, carbon tetrachloride, ammonium hydroxide, toluene and water to check the chemical resistivity of the composite. It was observed that the hybrid composites showed excellent resistance to chemicals and the tensile strength of alkali treated hybrid composite was also improved. The reason found that once the fiber subjected to alkali treatment, the amorphous hemicellulose can be removed to certain extent and eventually composite may show some crystalline behavior.
achieved various levels of success in improving fiber strength, alleviating water absorption and enhancing fiber–matrix adhesion in natural fiber reinforced composites. Many researchers in the past have developed composites using natural fibers such as bamboo , coir , sisal  and banana . The mechanical properties of the composites depend on fiber length, weight ratio, fiber orientation and interfacial adhesion between fiber and matrix . Due to noise pollution in many places in the world, there is a great need to find new sound absorbing materials that are capable of reducing the noise level at various frequency ranges . Traditionally, noise is controlled by using expensive and non-biodegradable sound absorbing materials such as glass wool, asbestos, polymer foams, fabric filler and polymer fibers, posing an added damage to the environment. As alternate, natural fibres like jute, cotton, kenaf, bamboo, flax, ramie, sisal, coir, luffa and hemp obtained from renewable resource can be used as a cheap, biodegradable and recyclable sound absorbing materials . The thermal stability of any natural fiber composite may also impose limitations in applications at temperatures that cause degradation of the fiber organic structure. In principle, the temperature not only degrades the structure, but also affects most properties of the natural fiber composites. A complete understanding of these effects requires a review on the composite basic thermo-gravimetric, i.e., weight loss with increasing temperature characterization . In this study, we have developed novel composite material using betelnut fiber reinforced with unsaturated polyester. The effect of chemicaltreatment onto betelnut fibers on mechanical, sound absorption and thermalproperties of composites has been investigated. The reinforcing property of the alkali treated fiber was also compared with that untreated fiber.
2 Sugar palm fiber which commonly known as ijuk fiber (Arenga pinnata), is the dark fibrous bark of sugar palm tree. For so many years, the fibers have been around for making various of product such as roof top, rope and brush (Ali et al., 2010; Azman, 2013; Bachtiar et al., 2008; Ishak et al., 2012, 2013; Mogea et al., 1991; Ticoalu et al., 2014). It is well known that sugar palm fiber has their advantages in tensile strength properties and can withstand longer life of degradation, which is less effected by heat and moisture compared to coirfiber; besides durable and having good resistance to sea water (Ishak et al., 2012). By having this unique properties, sugar palm a suitable material for making product that is water resistance such as rope, brooms, or used as filters to clear the water (Mogea et al., 1991). As for composite application, sugar palm fiber is still an unfamiliar used natural fiber as potential green fiber filler.
Surface treatment of natural fibers with various coupling agents is the more commonly used method for improving the fiber–matrix interaction. Coupling agents are molecules that possess two functions: the first is to react with OH groups of cellulose (pore sealing) and the second is to react with functional groups of which causes an increase in the number of chemical links . Coupling agents usually improve the degree of crosslinking in the interface region and provide perfect bonding . Several studies have reported on the effects of surface treatment of sisal fibers with various coupling agents on enhancement of the fiber durability and fiber–matrix interaction. For example, Canovas et al.  used timber extracts (colophony, tannin, and vegetable oil) to impregnate sisal fiber; this approach provided good results in terms of a reduction of more than 50% in the water absorption capacity of the fiber despite a small reduction in its tensile strength. Flexural test results showed that mortar reinforced with impregnated fibers exhibited better durability behavior than that reinforced with unimpregnated fibers. Toledo Filho et al.  evaluated the effects of treatment of aligned long sisal fiber with slurried silica fume on the durability of cement-based composites and verified that this treatment is an effective method for improving the strength and toughness of the composites with time. Silane coupling agents have been found to be effective in modifying the natural fiber–matrix interface; silane treatment of sisal fibers changes their surface topography, surface chemical structure, and thermal degradation [26; 27]. Singh et al.  used gamma-methacryloxypropyl trimethoxy silane as a coupling agent and verified that the moisture absorption of the surface-treated fibers reduced significantly on account of the hydrophobicity provided to the surface by long-chain hydrocarbon attachment.
In Aluminum alloys, heat treatment is one of the superior tools to improve mechanical properties. This is successfully proved in several research works. Among all types of heat treatment, solution heat treatment is the most popular one which significantly improve the microstructure of the alloy and in turns improve the mechanical properties by creating some strengthening phase as well as by improving the morphology of silicon. However in die cast aluminum alloys, entrapment of gaseous substances creates the main obstacle for the improvement of die cast aluminum alloys by heat treatment. NADCA (North American Die Casting Association) experienced that die castings are not usually solution heat treated. Low temperature agingtreatment may be used for stress relief or dimensional stability. A T2 or T5 temper may be given to improve properties. Because of the severe chill rate and ultra-fine grain size in die casting, their “as-cast” structure approaches that of the solution heat-treated condition. T4 and T5 temper results in properties quite similar to those which might be obtained if given full T6 temper. Moreover die castings are not generally gas or arc welded or brazed .
The present study shows some important effects of chemicaltreatment on the structure and mor- phology of coir fibre. The objective of the present study is to optimise overall properties of coir fi- bre so as to use coir fibre as a reinforcing agent in thermoplastic and thermosetting polymers. In the present study, coir fibre is treated with ferric nitrate salt. A thermaltreatment has been done at temperature of 1000˚C by using annealing method. X-ray diffraction of the treated coir fibre re- veals the crystalline nature of the fibre. Change in morphology has been found in coir fibre when subjected to scanning electron microscopy. Finally, the Fourier transform and infrared spectro- graphs show the presence of traces of iron oxide:fibre in the prepared composite.
The derivative weight changes due to applied heat in a closed chamber for the chemically modified and raw samples are shown in Figure 5. There is a peak below 60 °C was due to loss of moisture. From the figure it is clear that the pyrolysis of the raw jute fiber starts at about 350°C whereas this pyrolysis occurred at earlier temperature in the cases of treated fibers with different chemical concentrations. More specifically, it was 260–325 °C for RT, 225–275 °C for FT and 275–325 °C for WT. With the increase of chemical concentration for RT, the maximum value of derivative weight decreased. This indicated that with RT treatment, the activation energy increased gradually. In the case of FT, the weight change was lower at the concentration of 25% (F2), compared to the other concentrations (F1 and F3). In the case of WT, maximum derivative weight was found at the concentration of 15% (W2).Also, for the RT, FT, and WT jute fibers, derivative weights were 66.66%, 41%, and 45.83% lower respectively as compared to the raw jute fiber at the decomposition temperatures. In the case of RT, degradation occurred at 325 °C similar to the raw jute fiber, whereas WT and FT fiber degradations occurred at 300 °C, and 250 °C, respectively, as shown in Figure 5b. In case of all RT and WT modified jute fibers, only one wide pick appeared within the hemi cellulose and cellulose range. A similar conclusion was drawn by Kabir et al. [30,31].
Abstract— The interest in natural fiber-reinforced polymer composite materials is rapidly growing both in terms of their industrial applications and fundamental research. The natural fiber composites are more environmentally friendly. The main objective of this project is to investigate effect of chemicaltreatment and addition of chalk powder (additive) to the composite on thermal and mechanical properties of (Palmyra bract fiber) natural fiber reinforced polyester composites. The composites have been made by with and without chemicaltreatment to Palmyra fiber and addition of chalk powder to the polyester matrix. Mechanical properties such as tensileproperties (such as tensile strength, tensile modulus), Flexural properties (such as Flexural Strength, Flexural Modulus), Impact Strength when subjected to varying weights of fiber (0.5, 1, 1.5, 2, 2.5 grams) and thermalproperties such as conductivity, specific Heat capacity, thermal diffusivity of composites are studied.The tensile strength, flexural strength, impact strength of chemical treated fiber composite increased when compared with untreated fiber composite by increasing fiber content. Thermalproperties of treated fiber composite also increased when compared with untreated fiber composite. With addition of chalk powder to the treated composite Thermal conductivity, Specific Heat capacity, Thermal diffusivity of the composite are increased. But mechanical properties almost equal when compared to without addition of chalk powder to the composite.
Abstract Coir fibers were treated with sodium hydroxide (NaOH) and glutaraldehyde (GA). The influence of alkali and aldehyde treatment on thermal degradation and crystallinity of coirfiber was studied in detail. Thermogravimetric analysis and X-ray diffraction techniques were mainly used to characterize the coir samples. Activation energy of degradation was calculated from Broido and Horowitz–Metzger equations. NaOH-treated samples showed an increase in thermal stability. Removal of impurities such as waxy and fatty acid residues from the coirfiber by reacting with strong base solution improved the stability of fiber. Crosslinking of cellulose with GA in the fiber enhanced the stability of the material. Scanning electron microscopy was employed to analyze the change in surface morphology upon chemicaltreatment. Improvement in the properties suggests that NaOH and GA can be effectively used to modify coirfiber with excellent stability.
of fiber. As a result hydrophilic natural fibers absorb a large amount of water in the composite leading to failure by delamination from the matrix. Adequate adhesion across the interface can be achieved at desirable levels by better wetting and chemical bonding between fiber and matrix. To make good use of biofiber reinforcement in composites, fiber surface treatment can carried out to obtain an enhanced interface bonding between hydrophilic bamboo fiber and hydrophobic polymer matrixes. Besides such treatments will decrease the moisture absorption and hydrophilic character of bamboo fibers. Surface modification is therefore necessary to obtain better performance of the resulting composite. Kushwaha et el. used silane as interfacial coupling agents to form stable covalent bonds with both the mineral fiber surface and the resin . Chen et al. used cardanol as grafting agent in preparation for better performance of composite. In their experiment isocyanate silane and amino silane were used to modify the surface of bamboo fiber [15, 16]. In present research mimosa was used for grafting the surface of bamboo fiber. Grafting reaction is a practical technique to improve its dyeability, compatibility and hydrophobicity in economical way conducting chemical modification or polymerization reaction. Grafting enhanced the commercial viability and cost effectitiveness of the material. Man’s relationship with plant polyphenols is ancient. Mimosa is vegetable polyphenols tannis, which converted organic substance into stable materials, raised the denaturation temperature, resistance to putrefaction by micro-organisms in the environment. Chemically, mimosa is a polyphenol named 3,4-dihydroxy-2[[(3,4,5-trihydroxybenzoyl)oxa]oxan-2-yl]methol 3,4,5 trihydroxybenzonzte with molecular weight 36346866 g/mol having chemical formula C 27 H 24 O 18 . In
The approximate chemical composition of hemp fibre is: cellulose (70.2-74.4%), hemicelluloses (17.9-22.4%), lignin (3.7-5.7%), pectin (0.9%) and waxy substances (0.8%) (Mohanty et al. 2000). Moisture from the atmosphere comes in contact with the fibres hydrophilic hydroxyl groups form new hydrogen bonds with water molecules. Therefore, pectin and waxy substance hold these water molecules and hindering free hydroxyl groups to react with polar matrix. As a result, ineffective/poor bonding between hydrophobic resin and hydrophilic fibre occurs. This problem can be overcome by treating these fibres with suitable chemicals to decrease the hydrophilic hydroxyl group in the fibres. Chemicaltreatment such as alkalization and acetylation reacts with hydrophilic hydroxyl groups of natural fibre and improves hydrophobic characteristics and facilitates better bonding with matrix materials. Several authors used alkalization and acetylation treatments on natural fibres to improve its composites mechanical and thermalproperties. Leonard et al. (2007) used 0.16%NaOH treatment on hemp fibre for 48 hrs and found treated composites had 30% and 50% tensile and shear strength properties. Viviana et al. (2004) showed 4% higher thermal stability of hemp fibre after 8% NaOH treatment. Bledzki et al. (2008) used different concentration of acetylation treatment on flax fibres and reported 18% acetylation treatment showed 25% higher tensile and flexural properties.
I would like to express my special appreciation and thanks to my supervisor, Dr. Noor Ida Amalina binti Ahamad Nordin for her keen interest and esteemed guidance throughout the one year of this project. I would like to thank you for your never ending support during my tenure as research student under your guidance, for giving insightful comments and suggestions of which without it, my research path would be a difficult one. I would also like to thank all of my friends who supported me in writing, and motivate me to strive towards my goal. I am sincerely grateful to the staffs of Chemical Engineering and Natural Resources Faculty who helped me in many ways and made my stay in UMP pleasant and unforgettable. Last but not least, I would like to express my gratefulness to my parent for supporting me throughout the project, without them I could not complete my project work.
advantages of the renewability, low density and high specific strength (Ochi et al., 2008). Thus, the introduction of natural fiber such as coconut coir, kenaf, hemp, ramie, and flex has attractively influenced the production of biodegradable materials lately, especially in manufacturing industry (Bledski et al., 2002). Natural fiber like coconut coir can be used as replacement to the conventional fiber. The mixture between LDPE with coconut coir is the new material where natural fiber is mix with thermoplastic to improve the mechanical properties in terms of hardness, toughness and stiffness. Specifically, the good properties of coconut coir is suitable to use in the project because it lightweight, corrosion resistance, low to moderate cost, high thermal stability, has easy material ability process and make them as a reinforcement of choice by industry.