Nitrocellulose particle stability: Coagulation thermodynamics

The production of nitrocellulose (NC) creates large quantities of waste NC fines in wash water streams. Current processing techniques attempt to remove these fines by cross-flow microfiltration, air flotation, settling, centrifugation and lime precipitation. To date, no fundamental study investigating the interfacial thermodynamics of these fines has been reported. This work explored the stability of NC fines in water employing the DLVO model and the more recently developed extended DLVO (ExDLVO) model as described by van Oss and colleagues [van Oss C. J., Chaudhury M. K. and Good R. J. (1988) Chem. Rev. 88, 927–941]. Both models predicted that NC fines will become unstable and coagulate, with the addition of a 1:1 indifferent electrolyte at ionic strengths greater than approx. 5 mM. The ExDLVO theory, which accounts for Lewis acid-base (AB) interactions, predicted greater attractive potential energy availability. Experimental studies corroborated modeling predictions. Results indicate that NC fines may be easily destabilized allowing potential reuse.