Acid Hydrolysis of Cellulose in Concentrated Phosphoric Acid; Influences of Modified Groups of Cellulose on the Rate of Hy drolysis

Usuda, Makoto; Сузукі, Осаму; Nakano, Junzo; Migita, Nobuhiko

doi:10.1246/nikkashi1898.70.3_349

Cited by 13 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sulfuric acid is the most extensively used acid for preparation of CNCs and in the most commonly reported recipe, its concentration is 64 wt% with ratios of acid to cellulose of 8.75-17.5 mL g À1 and the hydrolysis proceeds at a temperature of 45 1C for 25-45 min. Nevertheless, hydrolysis with hydrochloric, [72][73][74] phosphoric, [75][76][77][78][79] and hydrobromic [80][81][82] acids has also been reported for this purpose. However, if the CNCs are prepared by hydrochloric or hydrobromic acid hydrolysis, their dispersion is very limited and their aqueous suspensions tend to flocculate.…”

Section: Cellulose Nanocrystalsmentioning

confidence: 99%

Key advances in the chemical modification of nanocelluloses

2014

View full text Add to dashboard Cite

Nanocelluloses, including nanocrystalline cellulose, nanofibrillated cellulose and bacterial cellulose nanofibers, have become fascinating building blocks for the design of new biomaterials. Derived from the must abundant and renewable biopolymer, they are drawing a tremendous level of attention, which certainly will continue to grow in the future driven by the sustainability trend. This growing interest is related to their unsurpassed quintessential physical and chemical properties. Yet, owing to their hydrophilic nature, their utilization is restricted to applications involving hydrophilic or polar media, which limits their exploitation. With the presence of a large number of chemical functionalities within their structure, these building blocks provide a unique platform for significant surface modification through various chemistries. These chemical modifications are prerequisite, sometimes unavoidable, to adapt the interfacial properties of nanocellulose substrates or adjust their hydrophilic-hydrophobic balance. Therefore, various chemistries have been developed aiming to surface-modify these nano-sized substrates in order to confer to them specific properties, extending therefore their use to highly sophisticated applications. This review collocates current knowledge in the research and development of nanocelluloses and emphasizes more particularly on the chemical modification routes developed so far for their functionalization.

show abstract

Section: Cellulose Nanocrystalsmentioning

confidence: 99%

Key advances in the chemical modification of nanocelluloses

2014

View full text Add to dashboard Cite

show abstract

“…To facilitate the use of CNCs hydrolysed with phosphoric acid in some of the applications described above, the hydrolysis procedure needs to be optimized and better understood. Although this method has been used in the literature [30,31], the resulting particles are often larger than sulfuric acid hydrolysed CNCs and tend to aggregate due to their low surface charge density [7,32,33]. These shortcomings make the CNCs difficult to work with; post-processing purification such as filtration of CNCs after sonication becomes extremely difficult and results in the loss of material as the aggregates are unable to pass through the normal paper or glass microfibre filters.…”

Section: Introductionmentioning

confidence: 99%

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

Vanderfleet

Osorio

Cranston

2017

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

Cellulose nanocrystals (CNCs) are emerging nanomaterials with a large range of potential applications. CNCs are typically produced through acid hydrolysis with sulfuric acid; however, phosphoric acid has the advantage of generating CNCs with higher thermal stability. This paper presents a design of experiments approach to optimize the hydrolysis of CNCs from cotton with phosphoric acid. Hydrolysis time, temperature and acid concentration were varied across nine experiments and a linear least-squares regression analysis was applied to understand the effects of these parameters on CNC properties. In all but one case, rod-shaped nanoparticles with a high degree of crystallinity and thermal stability were produced. A statistical model was generated to predict CNC length, and trends in phosphate content and zeta potential were elucidated. The CNC length could be tuned over a relatively large range (238-475 nm) and the polydispersity could be narrowed most effectively by increasing the hydrolysis temperature and acid concentration. The CNC phosphate content was most affected by hydrolysis temperature and time; however, the charge density and colloidal stability were considered low compared with sulfuric acid hydrolysed CNCs. This study provides insight into weak acid hydrolysis and proposes 'design rules' for CNCs with improved size uniformity and charge density.This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'.

show abstract

“…[116] The properties of CNCs are also affected by hydrolysis conditions such as acid type, acid concentration, reaction temperature, reaction ratio, and reaction time. [117][118][119] In addition, enzymatic hydrolysis [120] and TEMPO/NaClO/NaBr oxidation [121,122] are often used to prepare CNCs.…”

Section: Cellulose Nanocrystalsmentioning

confidence: 99%

Chiral Photonic Liquid Crystal Films Derived from Cellulose Nanocrystals

Duan

Cheng

Wang

et al. 2021

Small

View full text Add to dashboard Cite

As a nanoscale renewable resource derived from lignocellulosic materials, cellulose nanocrystals (CNCs) have the features of high purity, high crystallinity, high aspect ratio, high Young's modulus, and large specific surface area. The most interesting trait is that they can form the entire films with bright structural colors through the evaporation‐induced self‐assembly (EISA) process under certain conditions. Structural color originates from micro‐nano structure of CNCs matrixes via the interaction of nanoparticles with light, rather than the absorption and reflection of light from the pigment. CNCs are the new generation of photonic liquid crystal materials of choice due to their simple and convenient preparation processes, environmentally friendly fabrication approaches, and intrinsic chiral nematic structure. Therefore, understanding the forming mechanism of CNCs in nanoarchitectonics is crucial to multiple fields of physics, chemistry, materials science, and engineering application. Herein, a timely summary of the chiral photonic liquid crystal films derived from CNCs is systematically presented. The relationship of CNC, structural color, chiral nematic structure, film performance, and applications of chiral photonic liquid crystal films is discussed. The review article also summarizes the most recent achievements in the field of CNCs‐based photonic functional materials along with the faced challenges.

show abstract

Acid Hydrolysis of Cellulose in Concentrated Phosphoric Acid; Influences of Modified Groups of Cellulose on the Rate of Hy drolysis

Cited by 13 publications

References 0 publications

Key advances in the chemical modification of nanocelluloses

Key advances in the chemical modification of nanocelluloses

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

Chiral Photonic Liquid Crystal Films Derived from Cellulose Nanocrystals

Contact Info

Product

Resources

About