Ox Dation Resistant Cellulosc Pellice and Process for the Manuefacture Thereof

Content Provider	Semantic Scholar
Author	Rosser, Charles M. Ginski, Richard A.
Copyright Year	2017
Abstract	This invention relates to improved oxidation resistant cellulosic sheets, methods for preparing said sheets, and storage batteries incorporating said sheets as separators. Various processes and articles of manufacture where in cellulosic sheets or films are used require that they have improved resistance to oxygen and oxides. A prime example of a use of a cellulosic sheet or film requiring improved oxidation resistance is in storage batteries par ticularly of the zinc-silver electrode type employing one or more layers of semi-permeable membranes such as regenerated cellulose as a separator between the elec trodes and the alkaline electrolyte. The period of effec tive operation of this type of battery is limited by the deterioration of the separator caused by oxidation due in part to prolonged contact with the alkaline electrolyte and with electrolytically formed silver peroxide. Sev eral methods have been employed to increase the life of the cellulosic membrane thereby permitting an increase in the number of charging cycles. These include increas ing the number of layers of the film and/or incorporating a protective coating on the surface of the film, and/or incorporating various antioxidant materials in the coat ing or in the semi-permeable membrane. Another use for cellulosic membranes having im proved oxidation resistance is in dialyzing processes in corporating cellulosic semi-permeable membranes for the separation of various components in a solution. The need for improved oxidation resistant, semi-permeable membranes in dialyzing processes employing strong oxidizing material or material promoting oxidation is obvious. It is an object of the present invention to provide an improved oxidation resistant, cellulosic pellicle. It is another object of this invention to provide a proc ess for the improvement of the oxidation resistance of cellulosic sheets and films. It is still another object of this invention to provide a method employing a series of steps each of which in combination unexpectedly improves the oxidation resist ance of cellulosic sheets and films. It is a further object of this invention to provide stor age batteries having a longer useful life. It is a still further object of this invention to provide an improved storage battery employing a zinc-containing electrode, a silver-containing electrode, an alkaline elec trolyte solution and a highly oxidation resistant cellulosic membrane separating the electrodes from the electrolyte solution. In accordance with the present invention an improved oxidation resistant sheet comprises an alkali metal boro hydride-treated, non-fibrous, semi-permeable cellulosic pellicle such as regenerated cellulose and hydroxyalkyl cellulose ethers preferably having alkyl groups with from 2 to 4 carbon atoms. The borohydride-treated cellulosic pellicle is further improved by the incorporation therein O
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Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article