Transition characteristics of Brazilian vegetable fibers investigated by heating microscopy

Abstract

ABSTRACTStructural studies of three vegetable fibers plus eucalypt wood through heating microscopy, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and thermal analysis through Thermal Gravimetric Analysis/Differential Thermal Analysis are presented in this work. Morphological and dimensional changes obtained from heating microscopy were observed, showing shrinkage occurrences of vegetable fibers related to their diameter and length, respectively. The thickness decreased by 50% when heated at 450–500°C, this process starting at 300–400°C with an initial percentage length of ≈ 90%, that corresponds to a fast weight loss. These results were compared with simultaneous thermal analysis under the same conditions. Thus, for the first time, it was possible to quantify vegetable fiber dimensional changes and surface aspects under heating that cannot be seen by traditional thermal analysis. We also performed crystallinity calculations from XRD data, observing that cellulose/hemicellulose contents had major contribution in all samples.