Water Absorption Behavior of Teff (Eragrostis tef) Straw Fiber-Reinforced Epoxy Composite: RSM-Based Statistical Modeling and Kinetic Analysis

Abstract

Recently, reinforced polymeric composites prepared from natural fibers have received a significant interest among the researchers because of its appreciable sustainability, environmentally friendly, and low cost. However, one particular issue, that is, hydrophilic property, still needs to be addressed for its successful applications. Since the hydrophilic tendency of natural fibers is extremely undesirable, it leads to the quick degradation of fiber-based polymer composites. Hence, the fiber property, hydrophilic nature, is influenced by the presence of noncrystalline and voids part of these fibers that significantly influences the polymer matrix adhesion. Hence, it is very important to understand the water absorption behavior of reinforced fiber composites. In this study, a crop residual material specific to Ethiopia, teff straw (Eragrostis tef), was used as fiber material. The fiber was treated with 1% NaOH followed by 1% CH2=CHCOOH at room temperature for improving the bonding strength between the fiber and polymer, which leads to suppress the water absorption. The investigation on mathematical model for water absorption property at different fiber loadings (4%, 8%, 12%, 16, and 20%) was carried out, and the analysis on the kinetic behavior of water absorption was also investigated. In addition, the response surface-based statistical modeling which correlates water absorption, fiber loading, and time has been analyzed.