DÖKÜLEBİLİR PLASTİK BAĞLI BİR PATLAYICININ REOLOJİK OPTİMİZASYONU VE MEKANİK ÖZELLİKLERİNİN İNCELENMESİ

Abstract

Efficient utilization of the available resources in the defense industry is crucial, particularly for castable polymer-bonded explosives (PBX) like PBXN-109 and -110. The rheology of PBX is strongly influenced by the properties of its components, and the initial post-mixing viscosity significantly impacts casting quality. PBXN-109 formulations employed at the Defense Industries Research and Development Institute (SAGE) of The Scientific and Technological Research Council of Turkiye (TUBITAK), achieve successful casting attributable to their low viscosity. However, certain PBXN-110 formulations exceed the designated viscosity constraints. In this study, rheological properties of a PBXN-110 formulation were optimized by adjusting the energetic powder content and particle size distribution in monomodal, bimodal, and trimodal mixtures to reduce viscosity. Micromeritic analysis of cyclotetramethylene-tetranitramine (HMX) energetic powders was conducted to identify key physical parameters influencing viscosity, a critical factor in the explosive production line Spherical HMX particles with low Hausner ratio and compressibility index, indicative of enhanced flowability, and multimodal particle size distributions were identified as key factors for achieving lower viscosity. The influence of mean particle size on the initial viscosity was investigated, and it was shown that pre-coating the HMX particles with a plasticizer further reduces the initial viscosity. Mooney equation effectively showed the exponential dependence of initial viscosity of a bimodal Class 2 and Class 3 HMX suspension based on solid loading between 82–86%. The pseudoplastic shear thinning behavior of HMX suspensions was shown with the Oswald model based on a power law as a function of shear stress and shear rate. The non-Arrhenius temperature dependence of initial viscosity of HMX suspensions was presented by employing the Vogel-Fulcher-Tammann-Hess (VFTH) model. Statistical analyses based on micromeritic data highlighted that sphericity, bulk or tapped density, and mean diameter significantly influence the initial viscosity of the HMX suspension. These findings provide valuable insights for optimizing PBX casting processes by controlling the parameters that affect the initial viscosity of HMX suspensions.