科研之友
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摘要
In recent years, a new strategy of using citric acid (CA) to produce carboxylic cellulose nanocrystals (CNCs) has received attractive interest. However, mainly due to the weak acidity of CA, the CNC yield (about 10% without other assistance) is extremely low, which is the key factor that slows its advancement. This research applied short-time high-pressure microfluidizing to reinforce the production of CNCs after CA hydrolysis and investigated the effect of microfluidizing cycles on the yield and morphology of the CNC products, affording CNCs with good nanoscales (5-10 nm in diameter, 386-639 nm in length, 66-100 in aspect ratio and high yield (up to 56.8%). The prepared cellulose nanopaper (CNP) using the obtained CNCs showed highly transparency, high tensile strength (up to 178.51 MPa) as well as toughness (18.54 MJ/m(3)), and increased with the aspect factor of CNCs. Moreover, the presence of carboxylic groups (up to 0.60 mmol/g) was favorable to their dispersion stability. Furthermore, cellulose nanofibrils (CNFs) with high aspect ratio (98-147) were produced simultaneously after the separation of CNCs and more than 90% of the CA was easily recovered, which highly saved the consumption of mechanical energy and costs by deducing multi-cycles of centrifugation and large amounts of water usage which other CNC producing processes usually strictly required. The strategy proposed in this work opened up a new environment-friendly and economic route for the high-yield production of carboxylated CNCs with high aspect ratios and non-toxic CNC-based products that can be potentially used as platforms in wide range of applications. @@@ [GRAPHICS] @@@ .
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单位广州大学
