ORIGINAL PAPER Cellulose extracted from rice husk as filler for poly (lactic acid): preparation and characterization Daniele Battegazzore • Sergio Bocchini • Jenny Alongi • Alberto Frache • Francesco Marino Received: 16 December 2013 / Accepted: 17 February 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract The present manuscript has been focused on the extraction of cellulose from rice husk through a multi-step process. Three consecutive steps have been performed in order to separate impurities, hemicellu- lose, lignin and silica and thus to obtain pure cellulose. The crystallinity and morphology of the extracted cellulose have been investigated by using X-ray diffraction and scanning electron microscopy. Subse- quently, poly(lactic acid) (PLA) bio-composites with different filler contents (namely, 5, 10, 20 and 30 wt%) have been prepared by melt-blending. The thermal and mechanical properties of the resulting bio- composites have been investigated and correlated with the observed morphologies. In spite of a broad micrometric distribution of the cellulose particle size, the mechanical properties turned out to be strongly improved as well as the oxygen permeability proper- ties have proven to be reduced. These data have been compared with those of analogous compounds con- taining a commercial cellulose; the collected results have shown that similar mechanical properties have been found using both celluloses. Finally, this work has also demonstrated that an industrial waste as rice husk can be recycled for conferring enhanced final properties to PLA. Keywords Cellulose  Rice husk  PLA  Mechanical properties  Oxygen permeability Introduction Rice husk (RH) is an agricultural by-product material abundantly available in the world: Food and Agricul- ture Organization (FAO, report 2012) have estimated about 150 million tons in 2012. Indeed, RH has been already employed in different fields: as bio-fertilizer, as material for animal husbandry and absorbent material or pest control agent (Prasad and Pandey 2012). In addition, RH can be also used as a renewable fuel in cogenerating plants, considering its high calorific value (4,012 kcal/kg) (Tsai et al. 2007). Indeed, during its combustion, about 20–25 wt% of rice husk ash (RHA), containing more than 90 % silica with traces of other metal oxides, is produced (Patel et al. 1987). Such powder can be used as component in refractory bricks, as steel additive, as cement partial replacement (Prasad and Pandey 2012). In particular, Ashori et al. have investigated the effect of RHA as partial replacement of Portland cement (Torkaman et al. 2014) or as pozzolanic material (Hamzeh et al. 2013) or as filler for polymeric matrix (Nourbakhsh et al. 2011). D. Battegazzore (&)  J. Alongi  A. Frache  F. Marino Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Sede di Alessandria, Viale Teresa Michel 5, 15121 Alessandria, Italy e-mail: daniele.battegazzore@polito.it S. Bocchini Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, C.so Trento 21, 10129 Turin, Italy 123 Cellulose DOI 10.1007/s10570-014-0207-5