Hydrolysis, cellulose nanocrystal extraction

Kargarzadeh H, Ahmad I, Abdullah I, Dufrensne A, Zainudin SY, Sheltami RM. Effects of hydrolysis conditions on the morphology, crystallinity and thermal stability of cellulose nanocrystals extracted from kenaf bast fibers. Cellulose 2012 19 855-866. 

Starch occurs as a flour-like white powder, which is insoluble in cold water after its extraction from plants. Native starches contain between 15 and 45% of crystalline material. Starch crystallite, starch nanocrystal, microcrystalline starch and hydrolysed starch all refer to the crystalline part of starch, which are obtained by different extents of acidic hydrolysis. We will focus on starch nanocrystals. Cellulose nanocrystals are 100% crystalline materials, but starch nanocrystals consist of 45% crystalline portion. 

Menezes et al. [118] also extracted cellulose nanocrystals or whiskers of ramie fibres by acid hydrolysis. Acid hydrolysis of native ramie cellulose fibres leads to aqueous suspensions of elongated nanocrystals with high aspect ratio. The geometric average length and diameter were around 134 59 nm and 10.8 4.5 nm, respectively, giving rise to an aspect ratio around 12. A minimum of 228 and 70 measurements were used to determine the length and the diameter, respectively, of ramie whiskers. They noticed that more than 50% of the... 

Cellulose nanowhiskers (CNWs), also known as cellulose nanocrystals (CNCs) or nanocrystalline cellulose, are usually produced by the acid hydrolysis of natural cellulosic material after removing nonceUulosic substances such as dewaxing, hemicelluloses, and lignin. Most CNWs show a high crystallinity index and a lower aspect ratio. Thus it is expected that CNWs extracted from tunicates exhibit a high... 

Roman M, Winter WT (2004) Effect of sulfate groups from sulfuric acid hydrolysis on the thermal degradation behavior of bacterial cellulose. Biomacromolecules 5 1671-1677 DBS, Costa LA, Fonseca AF, Pereira FV, Druzian J (2015) Extraction and characterization of cellulose nanocrystals from com stover. Cellulose Chem Technol 49 127-133 Martinez-Sanz M, Lopez-Rubio A, Lagron JM (2011) Optimization of the nanofabrication by acid hydrolysis of bacterial cellulose nanowhiskers. Carbohd Polym 85 228-236... 

The extraction or isolation of crystalline cellulosic regions, in the form of rod-like nanocrystals, is a simple process based on acid hydrolysis that cleaves the cellulose fibers transversely. 

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