Investigation Into Mechanical And Tribological Behaviour Of Natural Fiber Reinforced Polymer Nanocomposite

Abstract

Material advancement along with environmental sustainability creates a quest among researchers for finding a suitable replacement of conventional materials as well as hazardous synthetic fibers. In this way, the most promising invention is the concept of polymer composites with bio fiber reinforcement. Natural fiber composites are a popular choice in the development of green materials as they possess high specific strength and low density, whilst being cost-effective, low energy consumption, environment friendly, and abundantly available. Despite the growing research and environmental sustainability of natural fibers, there utilization is limited to low end applications due to its comparatively much lower strength than synthetic fibers. Moreover, these fibers also suffer due to poor adhesiveness, higher hydrophilicity and lesser compatibility with polymer matrices. Hence, the use of natural fiber alone cannot fulfill the required strength and stiffness of the composites for high strength structural applications. These drawbacks of Natural Fiber Polymer Composites (NFPC) can be overcome by the concept of hybridization with synthetic fibers. The concept of hybridization enhances the use of sustainable natural fibers along with substantial reduction of hazardous and costly synthetic fibers. Additionally, partial replacement of synthetic fiber with suitable natural fiber also reduces the weight and cost of hybrid polymeric composite considerably with marginal or no loss of strength. Present scientific development of advanced materials creates a quest in between materials designer to discover such materials that possess superior structural along with distinct novel properties. Recently, nano-based polymer composites gained much importance because a small amount of nanoparticle reinforcement has ability to significant enhancement of the mechanical, thermal and physical properties of the polymer composites. Further, reinforcement of inorganic nanoparticles, like CNT, alumina and silica etc., into polymer matrix has been proved its efficiency to improve mechanical and tribological properties. Among various ceramic nano fillers, zirconia based three mol% yttria stabilized tetragonal zirconia polycrystal (3Y-TZP) nanoparticle is possessed a distinct vital properties. The crucial properties of 3Y-TZP nanoparticles are high transformation toughness, high melting point temperature, high strength, corrosion resistant, chemical stability, low thermal conductivity and excellent electrical insulation properties. 3Y-TZP particulates are widely used in high strength and wear resistant applications in enamels and dental restorations. Moreover,these particulates are also used in the field of refractory materials, thermal barriers and insulations. Further, very few literatures are available on zirconia based nano and micro particles as a filler application in polymeric composites for evaluation of mechanical properties. However, no literatures are found for such high strength and wear resistant 3Y-TZP nanoparticles for the filler applications in polymer composite to analyze their effect on mechanical and tribological properties. There are many sustainable natural fibers available on the earth in abundance. Most of it comes from forest, local habitat and agriculture. In which, Abaca (Musa textilis) is one of the strongest natural fiber among various existing bio-fibers whose potential in the field of tribological applications has not been explored till present date. Also their effect on hybridization with synthetic fiber like glass and 3Y-TZP nanoparticles on mechanical and tribological applications are not being investigated. Abaca plant is abundantly produced in humid subtropical regions of Philippines, Costa Rica, and Ecuador. This plant is also playing a crucial part in ecological aspects by avoiding the soil erosion and increasing the water logging capacity. The fiber quality of this plant could be recognized by its existing applications in the field of rope, twins, bank notes, rugs, mats, household construction, cordage industries and textile industries. These versatile applications have proved their worth as a structural material with reasonably good mechanical properties. A natural fiber used for reinforcement purposes should have possess the cellulose, hemicellulose and lignin with other constituents like carbon that make lighter in weight with high strength. The abaca fiber consists of 43.8% carbon, 63.7% cellulose, 18.55% hemicellulose and 15.1% lignin that conforms the utilization of this fiber as a reinforcement in polymer based composite structures. Against these background, the present work has been concentrated to established the following objectives: To evaluate the effect of hybridization and stacking sequence on the mechanical and tribological properties of developed composites. Synthesis of 3Y-TZP nanoparticles by suitable synthesis route in bulk along with economical aspects for filler applications in polymer hybrid composites. To study the favorable mechanical properties of developed hybrid and nanocomposites. An experimental investigation on abrasive and erosive wear analysis for developed hybrid and nanocomposites for tribological applications. For filler applications, 3Y-TZP nanoparticles are synthesized by different drying route and sintering temperatures under cost effective co-precipitation method. It is found that oven dry synthesis route at sintering temperature of 900° C is suitable for production of nanoparticles in bulk for filler applications in polymer composites. In this work, an attempt has been made to develop the abaca/glass hybrid composites by hand lay-up method with utilization of heat gun to minimizes the void content. The effect of hybridization and stacking sequences are evaluated for finding the optimum mechanical and tribological properties. Further, the effect of different doses of 3Y-TZP nanoparticles are analyzed on hybrid composite that have possesses the optimum mechanical and tribological properties. In the present investigation, it is found that hybridization of fiber and further nanoparticle reinforcement significantly enhances the mechanical and tribological properties. It is observed that GAAG (A and G represents abaca and glass fiber sequences respectively) composite showing the maximum tensile and impact strength while AGAG composite possesses the maximum flexural and inter laminar shear strength among various developed hybrid composites. It is also observed that with increase in nanoparticle amount from 1 to 3 wt.% enhances the mechanical strength. Further increase in nano amount up to 5 wt.% lead to decrease the strength. To study the tribological potential of developed hybrid and nanocomposites, abrasive and erosive wear experiments have been performed as per ASTM standards. It is found that AGGA hybrid composite showing the maximum wear resistant in both abrasive and erosive wear analysis. Further, AGGA3% nanocomposite possesses the maximum wear resistance followed by AGGA5% and AGGA1% nanocomposites. The influence of impingement angles on erosion rate established the semi ductile and semi brittle erosive wear behaviour of developed composites according to impact velocities. Further, morphological analyses are performed on SEM machine to observe the cause of failure due to fracture during mechanical tests and worn out surfaces during tribological investigations.