Microwave‐assisted molding of sisal/HDPEcomposites: Water absorption, diffusion kinetics and tribological behavior

Abstract

Recyclability and environmental safety have prompted research toward clean and energy‐efficient manufacturing technologies for natural fiber‐reinforced composites. In the current investigation sisal/HDPE composites were fabricated using a novel energy and time efficient microwave‐assisted molding (MAM) method. Sisal fibers were successfully treated with novel microwave‐assisted alkali treatment (MAAT) at 640 W microwave power. For the outdoor application the effect of treatment method on mechanical properties, water absorption, and tribological behavior of the developed composites were studied. The treated composites have been found to absorb less water by 45.28% as compared to untreated (UT). The developed composites recorded increase in tensile strength (36.5%), flexural strength (41.05%), and hardness (4.38%) as compared to UT composites, which could be attributed to effective partial removal of non‐cellulosic content after treatment from fiber surface. During the wear test, sisal/HDPE composite was employed as a pin, and the abrasive paper (P1000) served as a counter surface in the pin‐on‐disc (POD) arrangement for two‐body abrasive wear. The SWR, COF, and friction force values of the treated composites reduced by about 61.72%, 33.33%, and 34%, respectively, as compared to those for the UT composites at minimum normal load (10 N) and sliding speed (0.5 m/s) which was due to positive effect of MAAT. Scanning electron microscope was used to examine the worn surface of composites to understand the mode of wear mechanism.Highlights Novel microwave‐assisted alkali treatment (MAAT) was used for treatment of fibers. MAAT increased the fiber roughness. Microwave‐assisted molding was used for fabrication of composites. The water absorption behavior followed the Pseudo Fickian diffusion mechanism. Polymeric composites with MAAT fiber had optimum performance.