Mechanical behaviours of hybrid ensete/sisal fiber, reinforced polyethylene composite materials for injection moulding

Abstract

The present research work describes the development and characterization of a new set of natural fiber-based polymer composites consisting hybrid of false banana(Ensete) and sisal fibers as reinforcement and low-density polyethylene (LD-PE) and linear low-density polyethylene (LLD-PE) as polymer matrix and kaolin clay as filler using injection molding technique. This work aims to minimize the cost of raw materials needed for the plastic composite product fabrication process and optimized the composite manufacturing techniques on the injection molding process. In the present work, the effect of hybridization on mechanical properties of Ensete and sisal reinforced polyethylene (ESRF-PE) composite has been evaluated experimentally concerning their mechanical characteristics. The hybrid composites which contains 15% sisal and Ensete fiber with 75% LLD-PE matrixes (Composition, C3 at T2) have more tensile, flexural and compression strength than other composites can withstand the tensile strength of 66 MPa and flexural strength of 11.94 MPa and compression strength of 56.5 MPa followed by 20% sisal and Ensete fiber with 70% of the same matrices (composition C2 of T1 and T2) which holds 65 and 9.95 MPa respectively, which is 56.58%, 163.90%, and 69.43% higher than that of the non-reinforced PE respectively. It has been observed that the tensile strength of LD-PE-ESRF composite materials have an increase of about 9.92%, 39.60% and 25.62% concerning 15/75 (C1), 20/70 (C2), and 25/65 (C3) composition of fiber to matrix ratio. The water absorption in hybrid composites has been negligible. Because in 24 h, maximum and minimum water uptake has gain 0.1 and 0.6% respectively. To conclude, the highest rate of water uptake of natural fiber composites was 16.31%, which was obtained at 225 °C processing temperature and 25% fiber loading in 240 h. The results demonstrate that hybridization plays an important role in improving the mechanical properties of composites. Experiments are carried by keeping the volume ratio of Ensete and sisal (E:S) 2:3, 3:2 and 1:1, while the Shakiso kaolin was kept constant at 10%. The processing temperatures for injection molding(T1, T2, and T3) were 180, 200, 250 and 220, 250, 285 oC for LD-PE and LLD-PE respectively (the machine has five heating zone/areas), the last corresponding to the injection nozzle. The pressure, injection speed and screw position for LD-PE/LLD-PE were given as − 50/76 kg/cm2, 48/50% and 55.5/62 mm, respectively. The water absorption result, tensile, compression and flexural properties of these composites are markedly improved as compare to un-hybrid composites. Finally, the surface microstructure test has been done using an optical microscope to study a qualitative evaluation of the interfacial properties of Ensete and sisal reinforced fibers with polyethylene composite.