EFFECT OF ENVIRONMENTAL CONDITIONS ON ABSORPTION AND DEGRADATION BEHAVIOR OF SISAL/HDPE COMPOSITES FABRICATED USING MICROWAVE-ASSISTED MOLDING

Conventional manufacturing procedures for natural fiber-reinforced thermoplastic composites, such as sisal/high-density polyethylene (HDPE) composites, encompass compression moulding, injection moulding, or vacuum bagging processes. Recently, there has been a growing interest in exploring innovative manufacturing methods that are energy-efficient, environmentally friendly, and time-saving. Microwave energy has, therefore, gained attention for its time and energy efficiency, along with its environmentally friendly approach to processing polymer matrix composites (PMCs). The recent introduction of the novel microwave-assisted molding (MAM) method enables the fabrication of NFRCs, offering benefits like a rapid heating rate and volumetric heating, contributing to enhanced interfacial bonding performance. In this context, therefore, to continue benefiting from sisal/HDPE composites fabricated using the MAM method and to investigate their potential suitability for use in structural applications exposed to outdoor or wet environments, the absorption and degrading behavior of 10 wt.% sisal/HDPE composite were examined in various environmental conditions. Different environments were utilized, including tap water, sodium hydroxide (NaOH) solution (5%), and vegetable oil. The absorption behavior of the developed composites is thoroughly addressed for these liquid environments. The study also explored the mechanical properties (tensile and flexural) before and after exposure. The investigation revealed that the degradation in interfacial bonding between fibers and matrix decreased tensile and flexural properties. The water environment resulted in the maximum liquid absorption, whereas vegetable oil had the minimum. Compared to those conditioned in other environments, composites conditioned in a NaOH solution (5%) exhibited the highest level of property degradation.