Physical changes and FTIR analysis of kenaf core fiber heat treated in air

In this paper physical changes (hygroscopic and color properties) and FTIR analyses of kenaf core fiber heat treated in air were studied. The fibers were heated in air at temperature of 103, 165, 175, 185, 195 and 205 °C for 15 minutes. For physical changes hygroscopic and color analysis were carried out where moisture absorption and kenaf core color lightness were measured. FTIR of treated and untreated fibers were analyses to find possible changes in the spectrum and also relation between moisture absorption and OH groups of the fibers. Ratio between OH band height (3332 - 3346 cm-1) and absorbed moisture band height (1630 - 1640 cm-1) was used to find relation between absorbed moisture and OH groups. The results showed moisture absorption decreased as treatment temperature increased. However for fiber treated at 165 and 175 °C, moisture absorption was not significantly different. Fiber darkness only increased for fibers treated above 175 °C. FTIR results showed no substantial chemical changes between treatments; however, through deduction, heat treatment cause degradation of OH groups. As a conclusion, chemical modification that changes hygroscopic and color properties of fiber only minimum and possibly occurred at surface of fiber, thus cannot be detected directly by FTIR analysis.