The flow curves of nitrocellulose solutions on Hoppler viscosimeter

For the first time a possibility of an application of a Hoppler viscosimeter with the pressing ball for obtaining of the flow curves of 5-50% bipolymeric cellulose nitrates – polyvinyl nitrate (NC-PVN) solutions based on the measurements of the stationary velocity of a ball displacement along the wall of the cylindrical vessel has been checked experimentally. The relationships, rearranging the equations of the shear stress and rate by means of the correlation coefficients, underlie the method. The time of the ball immersion into the polymeric solution has been used as the main parameter, which is experimentally determined. The rheological flow law and the rheological parameters of reprocessing of 5-50% NC-PVN solutions in EA: a flow index, a consistency coefficient, have been established. It has been shown that 30-50% NC-PVN solutions in EA display properties of the non-Newtonian liquid to a greater degree and they are more structural ones in comparison with 5-20% NC-PVN solutions; the greater deviation of the flow index from 1 indicates on it. The values of the limit shear stresses that characterize the plastic (strength) properties of the polymeric compositions and allow to evaluate preliminary a possibility of a reprocessing of the nitrocellulose solutions, including the solutions, which are filled to the powders using the aqueous-dispersing, the lacquer-extrusion and the extrusion technologies, were found by the extrapolation of the rectilinear section of the flow curve to the axis of stresses. In the course of reprocessing of NC-PVN solutions in EA according to the aqueous-dispersing, the lacquer-extrusion and the extrusion technologies, the limits of a plasticity, corresponding to 90-1950 Pa, 1950-2750 Pa and 2750-5600 Pa, have been established. It has been shown, that the plasticity of NC-PVN die (50:50), filled with the octogen in the amount of 40 % by mass, increases ~1.7 times in comparison with the die, which is not filled, and it results in descreasing of a “brittleness” of the filled NC-lacquer.

ECOLOGICAL AND TOXICOLOGICAL ASSESSMENT OF HAZARD, POSED BY WATER CONTAMINATION OF WATER BODIES WITH POLYVINYL NITRATE

Water containing polyvinyl nitrate was experimentally assessed on the basis of organoleptic, general sanitary and toxicological indicators of harmfulness. It was established that that the compound did not change water organoleptic properties but produced a negative impact on viability of saprophytic microflora , nitrification processes and biochemical oxygen demand. Besides, in tests on animals. the substance caused acute, sub-acute and chronic toxicity. Based on those signs of harmfulness, threshold levels of exposure were established. Data obtained were taken into account for substantiation of MAC (Maximum allowable concentration) of polyvinyl nitrate in water bodies.

Overview on Energetic Polymers

Energetic materials for missiles, gun munitions or pyrotechnic devices often are mixtures in a biphasic form, with a filler and a binder. To satisfy the user needs, an analysis of functional requirements together with constraints (safety, vulnerability, ageing, environment, disposal, price...) is useful to choose a convenient binder. From this point of view numerous synthetic energetic polymers proposed or developed as binders are reviewed with regard to their syntheses, processing, properties and possible uses. These polymers contain explosophore groups: C-NO2 aliphatic or aromatic, ONO2, NNO2, NF2 and N3.Some research projects are suggested. Among them in the list of published polymers, following a NIMIC (NATO) suggestion, note the reason of a development interruption. Some dinitropolystyrene – polyvinyl nitrate mixtures or copolymers could exhibit interesting properties. For unknown reasons, some mixtures of crystalline filler- with polymeric binder, generally in a biphasic form, may also be monophasic for a same composition. What properties are modified between the both forms (e.g. combustion mechanisms, erosion, ideal character of the detonation) ? It is also interesting to pursue into a newly open route to thermo-plastic elastomers.