Preliminary Structural and Thermal Characterization of Conteira's (Hedychium gardnerianum) Fibers for Further Functionalization with Silica Colloidal Nanoparticles

The stem fiber of conteira (Hedychium gardnerianum) is one of the most abundant and available plant residues of the Azores (Portuguese Islands at North Atlantic) and has not yet been studied properly as vegetable fiber reinforcement. A preliminary study of its structural (chemical and physical) and thermal properties may reveal useful and practical specificities to select them for the various possible applications. In this study, the stem fibers were extracted by mechanical and chemical methods. The fibers composition, in terms of % of cellulose, hemicellulose, lignin and others (moisture, ash and extractors) were determined using standard test methods. The crystalline index, according the empirical method proposed by Segal, was obtained by XRD. H. gardnerianum fiber structure was also investigated by Fourier Transformed Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). To explore the potential of this fibers for a wide range of possible applications by changing their surface properties, we made the first attempt to functionalize this fibers with sol-gel silica nanoparticles, synthesized by a modified Stöber method. Results also shown that H. gardnerianum fibers have high crystallinity (69,77%), high cellulose content and thermal stability beyond 400 ºC. Finally, SEM micrographs show that stem fibers were successfully impregnated but the used rinsing process contributed to the removal of a huge number of nanoparticles.