Estimation of Main Constituents of Ananus comosus (Pineapple) Leaf Fiber and Its Photo-Oxidative Degradation

Abstract

An estimation of main constituents of pineapple leaf fiber (PALF) by conventional method was attempted and the values of 74.44% α-cellulose, 13.39% hemicellulose, 7.12% lignin, 2.89% pectic matter, and 0.58% aqueous extract were obtained. So, the main constituents of PALF are α-cellulose, hemicelluloses, and lignin. The molecular weight of raw, bleached PALF and α-cellulose of PALF were 1.517 × 105, 1.303 × 105, and 1.225 × 105, respectively. Bleached PALF was dyed with two dyes, Direct Green 27 and Acid Orange 52. Maximum dye exhaustion was found to be 98.97% for Direct Green 27 under the conditions of 3% dye concentration, 5% electrolyte concentration, and 70°C temperature, and 93.27% dye exhaustion was found for Acid Orange 52, where dyeing conditions were 4% dye concentration, 6% electrolyte concentration, and 80°C temperature. Dyeing time was fixed for 60 min for both dyes. The color fastness of PALF on exposure to sunlight has also been studied. It was observed that color fastness of raw fiber is higher than bleached fiber. The degradation of PALF under sunlight was studied by tensile strength and molecular weight measurements. Bleached fiber exhibited lesser loss of tensile strength and molecular weight than raw fiber. Infrared spectra (IR) of PALF were measured for different exposure times under sunlight. The PALF containing higher α-cellulose has good characteristics, similar to materials of higher molecular weight. For this, it gives high tensile strength, more dyeability, and better color fastness properties.