Exploring the Potential of Betel Nut Husk Fiber as Reinforcement in Polymer Composites: Effect of Fiber Maturity

This paper presents investigations on the effect of three different stages of fiber maturity (unripe, ripe and dried) on the physical, morphological and mechanical properties of betel nut husk (Areca catechu) (BNH). Density analysis, optical observation, moisture content and water absorption study were carried out to evaluate physical properties of BNH fiber. The fiber length and diameter were decreased with the increase of maturity stage from raw to ripe, while the density increased from raw to ripe. Mechanical properties of BNH fiber at different maturity were determined from single-fiber tensile tests where tensile strength, tensile modulus and elongation at break were found varied at each stages of fiber maturity. The difference in tensile strength of raw, ripe and dried BNH fiber is attributed to the structural changes in the plant cell wall during the ripening stage from immature to fully ripening stages. Modulus of natural fiber is also related to the lignin content in the fiber. Water absorption was found to be the highest for raw BNH fiber and the lowest water absorption was observed in dried BNH fiber. Highest moisture content was observed in ripe BNH fiber and the lowest was in dried BNH fiber due to moisture lost during fruit ripening. The diameter of lumen in raw BNH is larger than that of lumen of ripe BNH fiber, while dried BNH fiber showed more compacted structure of fiber.