狠狠色丁香久久综合婷婷亚洲成人福利在线-欧美日韩在线观看免费-国产99久久久久久免费看-国产欧美在线一区二区三区-欧美精品一区二区三区免费观看-国内精品99亚洲免费高清

 

文獻(xiàn)名： Carboxylated Cellulose Nanocrystals with Chiral Nematic Property from Cotton by Dicarboxylic Acid Hydrolysis

 

 

作者： Chunxiang Lin^abc，Beiqiu Chen^a，Yushi Liu^a，Yiting Chen^b，Minghua Liu^a，J.Y Zhu^c

^a College of Environment & Resources, Fuzhou University, Fuzhou, 350108, China

^b Fujian Provincial University Engineering Research Center of Green Materials and Chemical Engineering (Minjiang University), Fuzhou, 350108, China

^c Forest Products Laboratory, U.S. Department of Agriculture, Forest Service, Madison, WI, 53726, USA

 

 

 

摘要：Carboxylated cellulose nanocrystals (CNCs) were produced from cotton linter using a mixture of a dicarboxylic acid (maleic acid or succinic acid) and its corresponding anhydride with or without catalyst in acetic acid as solvent. The low solubilities of these dicarboxylic acids can ease chemical recovery and decrease environmental impact (especailly maleic acid is a U.S. FDA approved indirect food additive (21CFR175-177)) and capital costs compared with the conventional concentrated sulfuric acid hydrolysis for producing CNCs. The dicarboxylic-acid-produced CNCs (DC-CNCs) contained surface carboxyl groups of approximately 0.5?mmol/g, with ranges of dimensions of 50–150?nm in diameter and 50–700?nm in length. Birefringence was observed in the DC-CNC suspensions above critical concentrations. However, fingerprint texture was only observed in the DC-CNC suspensions produced with catalyst p-toluenesulfonic acid. Scanning electron microscopy images of the cross section of DC-CNC films revealed a periodic ordered multilayer structure. DC-CNCs were also produced using recycled dicarboxylic acids.

 

關(guān)鍵詞：Cellulose nanocrystals，Dicarboxylic acid hydrolysis，Chiral nematic，Birefringence