Effect of the properties of cellulose acetate solutions on the characteristics of porous films formed from them

1975 ◽  
Vol 17 (3) ◽  
pp. 571-575 ◽  
Author(s):  
L.P. Perepechkin ◽  
N.N. Barabanov ◽  
N.V. Barykina ◽  
V.P. Dubyaga ◽  
G.P. Barykin ◽  
...  
2020 ◽  
Vol 58 (6) ◽  
pp. 812-817
Author(s):  
S. I. Lazarev ◽  
Yu. M. Golovin ◽  
S. V. Kovalev ◽  
D. S. Lazarev ◽  
A. A. Levin

Author(s):  
H. K. Plummer ◽  
E. Eichen ◽  
C. D. Melvin

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.


Author(s):  
R. A. Crellin ◽  
G. O. Brooks ◽  
H. G. Horsewell

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


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

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