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Effect of the Molecular Structure and Molecular Weight of Poly(Vinylidene Fluoride-Chlorotrifluoroethylene) Copolymers on the Characteristic Properties of TATB-based Composites

Singh Arjun, Sharma Tirupati Chander, Kumar Mahesh

Central European Journal of Energetic Materials

2020

Vol. 17, no. 3

428--450

1,3,5-Triamino-2,4,6-trinitrobenzene (TATB) based composites with different molecular weights and molecular structures of poly(vinylidene fluoride-chlorotrifluoroethylene) (poly(VDF-CTFE) binder were studied to investigate their effect on the physical, thermal, mechanical and explosive properties. The poly(VDF-CTFE) with three different kinds of molecular weights (FKM1, FKM2 and FKM3 samples) and three different kinds of molar ratios of VDF and CTFE (FKM4, FKM5and FKM6) was chosen as the polymeric binder. The experimental results indicated that all of these kinds of TATB-based composites do not show any measurable changes in the particle density, detonation velocity and impact sensitivity. The thermal data revealed that weight loss occurs in two steps and, that the thermal stability deceases slightly with an increase in the molecular weight. On other hand, the weight loss occurred in a single step and the thermal stability increases slightly with an increase in the molar ratio of the CTFE to VDF monomer units. The adhesion properties between the two phases of TATB crystals and polymeric matrices rely on the properties of the interface, which is expressed in terms of the mechanical properties. The storage modulus decreases with increasing molecular weight. On other hand, an increase in the CTFE to VDF molar ratio in the poly(VDF-CTFE) binder remarkably improves the mechanical strength. FKM5-9505 shows a significant reduction in creep deformation and dramatically increases the elongation failure, compared to those of the FKM4-9505 sample. Finally, SEM observations clearly suggested that the coating of the polymer matrix onto the surface of the TATB crystals is clearly demonstrated.

Synthesis and Thermal Properties of Cerium-Dysprosium Oxide

Mikuśkiewicz M., Stopyra M., Moskal G.

Archives of Metallurgy and Materials

2016

Vol. 61, iss. 2B

965--969

The paper presents results of investigation on synthesis and characterization of cerium-dysprosium oxide. The input powders - dysprosium oxide Dy,sub>2O3 and cerium oxide CeO2 - were mixed so as to obtain equimolar ratio of cations, milled in alcohol and synthesized via solid state reaction process at 1350°C under 15MPa in vacuum for 2h. The microstructure, phase composition and thermal properties were analyzed. The obtained material was multiphase. Non-stoichiometric compounds were identified. Thermal diffusivity of investigated material decreased in the temperature range of 25-1000°C from 0,71 to 0,45 mm2/s.