Cellulosic nanoparticles from alfa fibers (Stipa tenacissima): extraction procedures and reinforcement potential in polymer nanocomposites
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The microstructure and chemical composition of alfa (Stipa tenacissima) were investigated. The polysaccharide and lignin contents were around 70 and 20 wt%, respectively. From the bleached and delignified fibers, two types of nanosized cellulosic particles were extracted, namely cellulose nanocrystals and microfibrillated cellulose (MFC). The former correspond typically to the elementary crystallite units of the cellulose fibers, with a rod-like morphology and an aspect ratio of about 20. The latter, mechanically disintegrated from oxidized bleached fibres, presents an entangled fibrillar structure with widths in the range 5-20 nm. The reinforcing potential of the ensuing nanoparticles was investigated by casting a mixture of acrylic latex and aqueous dispersion of cellulose nanoparticles. Thermo-mechanical analysis revealed a huge enhancement of the stiffness above the glass transition of the matrix. Significant differences in the mechanical reinforcing capability of the nanoparticles were reported.
KeywordsAlfa Structure Nanocrystals Microfibrillated cellulose (MFC) Nanocomposites
The authors thank for their financial support Hassan II Academy of Sciences and Techniques, the French Ministry of Foreign Affairs (Corus program 6046), the PHC-UTIQUE (Grant 11/G 1115) and the Tunisian Ministry of Higher Education and Scientific Research.
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