Extraction and fractionation of a lignocellulosic biomass and its use as a bio-filler in poly(3-Hydroxybutyrate)

A lignocellulosic biomass, biowaste of second generation bioethanol production, was treated with a toluene/ethanol mixture and with water in order to leach organic and water soluble extractives. Moreover, the parent lignocellulosic biomass was fractionated in order to isolate its main components: Acid-insoluble lignin and holocellulose (hemicelluloses and cellulose). The extractive-free solid residues and the isolated fractions were studied through scanning electron microscopy, vibrational spectroscopy and thermogravimetry. Subsequently, the lignocellulosic biomass and its derivatives were used as bio-fillers in poly(3-hydroxybutyrate) (PHB), a microbial biodegradable polyester. The obtained blends were compression-molded to produce films. The unprocessed blends were characterized by means of thermogravimetric analysis, while the dumbbell-shaped films were analyzed through tensile tests. A slight increase of thermal stability and a modest stiffening of the PUB matrix were detected.