Nanocellulose was prepared by acid hydrolysis of microcrystalline cellulose (MCC) at different hydrobromic acid (HBr) concentrations. Polyvinyl alcohol (PVA) composite films were prepared by the reinforcement of nanocellulose into a PVA matrix at different filler loading levels and subsequent film casting. Chemical characterization of nanocelluloses was performed for the analysis of crystallinity (X c ), degree of polymerization (DP), and molecular weight (M w ). The mechanical and thermal properties of the nanocellulose reinforced PVA films were also measured for tensile strength and thermogravimetric analysis (TGA). The acid hydrolysis decreased steadily the DP and M w of MCC. The crystallinity of MCC with 1.5 M and 2.5 M HBr showed a significant increase due to the degradation of amorphous domains in cellulose. Higher crystalline cellulose showed the higher thermal stability than MCC. From X-ray diffraction (XRD) analysis, nanocellulose samples showed the higher peak intensity than MCC cases. Reduction of MCC particle by acid hydrolysis was clearly observed from scanning electron microscope (SEM) images. The tensile and thermal properties of PVA composite films were significantly improved with the increase of the nanocellulose loading.

Chemical modifications of wood fibers (Lignocel V R C120) were performed for biocomposite applications, and chemically modified wood fibers were analyzed by FTIR spectroscopy. NaOH treatment showed band shifts from Cell-I to Cell-II in FTIR spectra from 2902 cm ) and a strong absorption at 1272 cm À1 for CAO band in aromatic ring.

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Wood flour (WF) and talc-filled polylactic acid (PLA) composites are prepared by melt compounding and injection molding. The effects of filler loading and silane treatment, the thermal and mechanical properties of the composites are studied. Loading of WF and WF/talc mixture into neat PLA results in a small decrease in the glass transition and crystalline temperatures of the composites. The use of WF, talc and silane in the composites causes successively larger decreased in the composite crystallinity. The addition of talc and silane to PLA/WF composites improved the tensile modulus. The tensile strength of the composites decreases slightly with the addition of talc, but it considerably improves with the use of 1 wt% silane. Morphological analysis shows improved interfacial bonding with silane treatment for the composites.

Abstract. Nanocomposites with polypropylene/clay/wood flour were prepared by melt compounding. Thermal, mechanical and morphological properties were characterized. The addition of clay, compatibilizer and wood flour considerably improved the thermal stability (i.e., decomposition and melting temperatures) of the hybrids. The tensile modulus and strength of most hybrids were highly increased with the increased loading of clay, MAPP and wood flour, compared to the hybrids without wood flour. The wide angle X-ray diffraction (WAXD) patterns showed the increased d-spacing of clay layers, indicating enhanced compatibility between PP and clay with the addition of maleated polypropylene (MAPP). The transmission electron microscopy (TEM) photomicrographs illustrated the intercalated and partially exfoliated structures of the hybrids with clay, MAPP and wood flour.