Property and Preparation of Polyethenol Nitrate

Polyethenol nitrate (nitro polyethenol) is a synthetic polymer to replace cellulose nitrate. It was first studied in 1929. Polyethenol was dissolved into concentrated sulfuric acid at 0 °C. The solution was then slowly added to a mixed acid of nitric acid and sulfuric acid and gradually heated to 40-50 °C. Polyethenol nitrate was precipitated out. The plastic precipitate was then filtered and washed to become firagile products with a nitrogen content of 10 %. In the nitration of polyethenol in 10-20 °C, polyethenol is easy to be oxidized. Thus, the oxidation should be prevented by some methods. 

Hydroxyl groups of polyethenol cannot be completely esterified whatever in the mixed acid of nitric acid-suUuric acid or nitric acid-acetic acid because of the cohydrolysis. It is nitrated by a mixture of nitric acid-acetic acid or a nitric acid-carbon tetrachloride solution. The high nitrated product can be softened at 40-50 °C. The lead-block value of polyethenol nitrate with a nitrogen content of 13-15 % is 153-342 cm. 

The nitrogen content of polyethenol nitrate is generally in a range of 13.5-14.5 %, while the theoretical maximum nitrogen content is 15.75 %. The detonation velocity of polyethenol nitrate is similar with cellulose nitrate, which has the same nitrogen content as polyethenol nitrate. The detonation velocity of polyethenol nitrate with a nitrogen content of 13.4 % in a paper cylinder with a diameter of 30 mm is shown below. 

Polyethenol nitrate is flammable and infusible. It has not been used in industry because of its poor chemical stability. Different from cellulose nitrate, which can be existed as a solution and be a highly mechanical film after evaporation of the solution, polyethenol nitrate cannot be formed as a solution. It might be because of the shortage of oriented molecular chains. 

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