Testing Methods: Acidity in Nitrocellulose

3.1 Procedure

2 gm of dried Nitrocellulose (following the procedure given in 1.2) are weighed accurately and taken in a clean, dry 250 ml stoppered conical flask. To this, 90 ml of acetone is added, the stopper returned and the flask is agitated till Nitrocellulose dissolves. 10 ml of distilled water is added and the flask is shaken to dissolve any precipitated Nitrocellulose. To the solution, 0.5 ml of mixed indicator (neutral red and bromocresol green) is added and the solution is titrated with 0.01 N NaOH until a green colour appears. A blank titration is carried out using 90 ml of acetone, 10 ml of distilled water and 0.5 ml of the indicator.

Acidity as % H2SO4 = [(Titre-Blank) x 0.049 x f ] weight of sample taken

Where f = Factor of 0.01 N NaOH used.