Alkali treatment and its effect on tribological properties of naturally woven coconut sheath polyester composite

In the recent years natural fibres have drawn great interest for its bio-degradability, low cost and its availability in nature. Among different types of natural fibres, naturally woven coconut sheath fibres are one of the recently explored alternatives for synthetic fibres. These fibres are generally treated with alkali for enhancing mechanical properties and reinforcing characteristics. Tribological applications like gears, cams, bearings, etc. can be benefited from such composites. In most cases chemical treatment are done favouring the structural properties however, their influence on tribological properties are rather not considered. In the current research, hybrid composites (polyester resin with naturally woven coconut sheath (N) and glass fibres (G)) were tested against hardened steel counterface in a pin on disc configuration. Tests were performed at 40 N normal force and 3.5 m/s sliding velocity. From the results all hybrid combinations except (NNN) shows degrading wear properties with the alkaline treatment. The friction properties are modified by having low friction coefficients for all combinations except NGN and GGG hybrids. From the observed SEM images the surface morphology of NNN hybrid significantly differs from the rest of the combinations in both treated and untreated specimens. The partial removal of individual phase (resin) prevails in untreated specimen for which the fibres are highly visible. However, such phenomenon is not dominant in the alkali treated material showing better reinforcing behaviour complimenting low friction properties. The alkali treated specimen has reduced fibre size comparing the untreated specimen which results in low wear resistance. Compromise between friction and wear properties between each other the untreated fibres are best suited for tribological applications. Furthermore, investigations on treatment process and other treatments might have some influence in tribological behaviour

Dry sliding wear properties of Jute/polymer composites in high loading applications

In the last few decades natural fiber composites has gained its importance due to its low cost and their availability as additives with minimal processing. Amongst the various natural sources the Jute fiber is chosen in the present research due to its fiber structure and good physical and mechanical properties. In this background natural fiber composites of unsaturated polyester were reinforced with jute fibers. While most research on green composites focuses on the structural characteristics, the present work investigates the suitability of the material to be used as a tribocomposite. Tailor made hybrid composites were made with chemically treated (NaOH) jute fiber and 2 wt % PTFE filler (tribo lubricant) to obtain the better tribological characteristics in high loading condition. Tribotests were performed on flat on flat configuration where 100Cr6 steel was used as counterface material. A pv limit of 400 MPa-mm/s (10KN and 100 mm/s) was attainedin a flat-on-flat configuration for studying the tribological properties. The static and dynamic coefficient of friction was found to be 0.15 and 0.07 respectively.An exponential increase in temperature was observed throughout the test. The material failure was observed within 500 m of sliding distance where pulverization of matrix due to thermal degradation is evident. Wear mechanisms such as fiber breakage, polymer degradation, fiber thinning and fiber separation was observed. From the present investigation the low cost Jute fabric composites havinglow frictional coefficient seemed to be a alternative to the bearing materials working at higher contact pressure and low velocity

Studying mechanical, thermal and absorption, characteristics of water hyacinth (Eichhornia crassipes) plant fibre reinforced polymer composites

The natural fibre extracted from water hyacinth waste could be used for making natural fibre polymer composites. The main intent of this manuscript is to develop polymer composite materials reinforced by aquatic wastewater hyacinth natural fibre having varying lengths. The water hyacinth fibres were extracted using a mechanical drum extractor followed by a drying process at a speed of 320 rpm. Mechanical testing of the composites was conducted as per the relevant ASTM standard and subsequently, thermo gravimetric analysis was also conducted to assess the thermal characteristics of the composites. Fourier-transform infrared spectroscopy (FTIR) and X-Ray diffraction (XRD) techniques were employed to characterize the elemental and microstructural properties of the composites. A 20 mm fibre length with a 30% fibre content resulted the best mechanical properties. Fractured surfaces from the composite samples are evaluated by using a scanning electron microscope (SEM). Brittle fracture, fibre pulled out, fibre clusters are identified as the general failure characteristics of the composites. This study demonstrated that the hyacinth fibre reinforced epoxy resin composite could be useful for developing particleboard products, as well as other lightweight products

Exploration of tribological characteristics of naturally woven fiber composites

Natural fiber composites (NFC) being one of the new interventions in the composite industry, is given less importance for tribological applications. In the current research, an in-depth study is made to understand the influence of normal force and speed, affecting the tribological characteristics. Various forms of lignocellulosic fibers exist, out of which coconut fibers are advantageous due to its naturally woven state. Tribological characterization was performed using a ball on disc configuration. Online measurements of friction force elucidate that the friction characteristics of naturally woven coconut sheath reinforced polymer (CSRP) composite stabilize at increased speed. Moreover, the orientation of the fiber strongly influences mode of wear

Green Corrosion Inhibition on Carbon-Fibre-Reinforced Aluminium Laminate in NaCl Using Aerva Lanata Flower Extract

Aluminium-based fibre–metal laminates are lucrative candidates for aerospace manufacturers since they are lightweight and high-strength materials. The flower extract of aerva lanata was studied in order to prevent the effect of corrosion on the aluminium-based fibre–metal laminates (FMLs) in basic media. It is considered an eco-friendly corrosion inhibitor using natural sources. Its flower species belong to the Amaranthaceae family. The results of the Fourier-transform infrared spectroscopy (FTIR) show that this flower extract includes organic compounds such as aromatic links, heteroatoms, and oxygen, which can be used as an organic corrosion inhibitor in an acidic environment. The effectiveness of the aerva-lanata flower behaviour in acting as an inhibitor of the corrosion process of FMLs was studied in 3.5% NaCl solution. The inhibition efficiency was calculated within a range of concentration of the inhibitor at room temperature, using the weight-loss method, potentiodynamic polarization measurements and electrochemical-impedance spectroscopy (EIS). The results indicate a characterization of about 87.02% in the presence of 600 ppm of inhibitor. The Tafel curve in the polarization experiments shows an inhibition efficiency of 88%. The inhibition mechanism was the absorption on the FML surface, and its absorption was observed with the aid of the Langmuir adsorption isotherm. This complex protective film occupies a larger surface area on the surface of the FML. Hence, by restricting the surface of the metallic layer from the corrosive medium, the charge and ion switch at the FML surface is reduced, thereby increasing the corrosion resistance