Activating cellulose via its reversible reaction with CO2 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene for the efficient synthesis of cellulose acetate

2015 ◽  
Vol 17 (5) ◽  
pp. 2758-2763 ◽  
Author(s):  
Yunlong Yang ◽  
Longchu Song ◽  
Chang Peng ◽  
Enhui Liu ◽  
Haibo Xie
Keyword(s):  
Cellulose Acetate ◽  
Reversible Reaction ◽  
Efficient Synthesis ◽  
Cellulose Acetates

Reversible reaction of cellulose with CO2 in DMSO/DBU results in a derivative dissolution of cellulose, which can be applied for the efficient acetylation of cellulose to afford cellulose acetates with degrees of substitution from 1.78–2.89.

Synthesis and Characterization of Cellulose Acetate Blend Ultrafiltration Membranes： The Effect of Degrees of Substitution

2013 ◽  
Vol 634-638 ◽  
pp. 2072-2076
Author(s):  
Lin Lin Kong ◽  
Da Lun Zhang ◽  
Zi Qiang Shao ◽  
Bai Xin Han ◽  
Ya Liang Chen
Keyword(s):  
Cellulose Acetate ◽  
High Performance ◽  
Permeate Flux ◽  
Ultrafiltration Membranes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Phase Inversion Technique ◽  
Blend Membranes ◽  
Cellulose Acetates ◽  
Hydrophilic Membrane

Cellulose acetate (CA), a hydrophilic membrane material, was selected to prepare ultrafiltration membrane for the aim of achieving high-performance membranes with respect to flux and rejection characteristics. In order to prepare membranes with improved properties, blending of cellulose acetates with different degrees of substititution(DS) has been attempted. In this study, polymeric blend ultrafiltration membranes based on cellulose acetate with different DS were prepared by phase inversion technique. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle are used to understand the influence of DS on the properties of modified membranes. The blend membranes prepared were subjected to the separation of egg albumin (EA). The separation and permeate flux efficiencies of the blend membranes were discussed.

Cellulose Acetate Reverse Osmosis Membrane Structure

1972 ◽  
Vol 30 ◽  
pp. 528-529
Author(s):  
H. K. Plummer ◽  
E. Eichen ◽  
C. D. Melvin
Keyword(s):  
Cellulose Acetate ◽  
Reverse Osmosis ◽  
Membrane Structure ◽  
Freeze Drying ◽  
Dense Layer ◽  
Water Removal ◽  
Reverse Osmosis Membrane ◽  
Correct Interpretation ◽  
Electron Image ◽  
Scanning Electron

Much of the work reported in the literature on cellulose acetate reverse osmosis membranes has raised new and important questions with regard to the dense or “active” layer of these membranes. Several thickness values and structures have been attributed to the dense layer. To ensure the correct interpretation of the cellulose acetate structure thirteen different preparative techniques have been used in this investigation. These thirteen methods included various combinations of water substitution, freeze drying, freeze sectioning, fracturing, embedding, and microtomy techniques with both transmission and scanning electron microscope observations.It was observed that several factors can cause a distortion of the structure during sample preparation. The most obvious problem of water removal can cause swelling, shrinking, and folds. Improper removal of embedding materials, when used, can cause a loss of electron image contrast and, or structure which could hinder interpretation.

A new facile and efficient synthesis of trans-(+)-sobrerol by biotransformation of α-pinene using extremophiles microorganisms

Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
LA Vilaseca ◽  
J Quillaguamán ◽  
L Fuentes ◽  
O Sterner
Keyword(s):  
Efficient Synthesis

The Control of Cigarette Smoke Deliveries Using Heat-Shrinkable Films

1975 ◽  
Vol 8 (2) ◽  
Author(s):  
R. A. Crellin ◽  
G. O. Brooks ◽  
H. G. Horsewell
Keyword(s):  
Particulate Matter ◽  
Cellulose Acetate ◽  
Cigarette Smoke ◽  
Total Particulate Matter ◽  
Puff Volume ◽  
Cigarette Paper ◽  
High Degree

AbstractA ventilating filter for cigarettes has been developed which reduces the delivery of smoke constituents from the final two to three puffs. Since the normaI delivery for these three puffs can account for up to half the total particulate matter and nicotine delivered by the whole cigarette, usefuI reductions per cigarette can be produced. The ventilating filter consists of cellulose acetate tow wrapped in heat-shrinkable film and attached to a tobacco rod using perforated tipping paper. When the cigarette is smoked, the perforations remain closed by contact with the impermeable film until transfer of heat to the filter is sufficient to soften the filter tow and shrink the film. Ventilating air now enters the cigarette and reduces the smoke deliveries. The effectiveness of the ventilating filter is increased by using films which have a low shrink temperature, high shrink tension and a high degree of biaxiaI shrinkage. Increases in filter plasticiser level, tipping perforation area and puff volume improve the effectiveness of the ventilating filter but increases in cigarette paper porosity and tobacco butt length reduce the effectiveness

Characteristics and Potential Applications of Cellulose Acetate

2014 ◽  
Vol 68 (9) ◽  
pp. 1018-1024
Author(s):  
Shu Shimamoto ◽  
Shizuka Okada ◽  
Toshikazu Nakamura
Keyword(s):  
Cellulose Acetate ◽  
Potential Applications
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