Effect of Manufacturing Processes on Nitrocellulose in Extruded Double Based Propellant.

摘要

Extruded Double Based (EDB) propellants are widely used in civilian and military applications. A major component of EDB propellants is the energetic polymer Nitrocellulose (NC), which acts as a binder and gives the propellant its structural integrity. The length of the nitrocellulose polymer chains has a significant impact upon the mechanical properties of the composition. EBD propellants also contain nitro-glycerine (NG), which increases the energy content of the composition, and changes the mechanical properties of the composition as it acts as a plasticizer. The mechanical properties of the propellant are crucial to the correct and safe functioning of the propellant. They are dependant upon the polymer chain length and NG content; it is of great importance for safety reasons to understand if there are changes during extrusion, such as increased chain scission at the surface, migration of plasticizer.It is thought that the mechanical work involved in the production of EDB propellants leads to polymer degradation (chain scission). This work investigates the effect of the extrusion on the mechanical properties and polymer chain length of the nitrocellulose was analysed using Dynamic Mechanical Analysis (DMA), Micro hardness Testing and Gel Permeation Chromatography (GPC). The thermal transition events that occur in EDB propellants have also been investigated with Differential Scanning Calorimetry (DSC) and DMA.