The present work presents combustion simulations of hydroxyl-terminated liquid polybutadiene loaded with ammonium perchlorate and aluminum, using Chemkin software and the “Plug Flow” type reactor. These materials are widely used in solid composite propellant formulations. Through this study, the effect of parameters of axial velocity, equivalence ratio, pressure and temperature during the firing of the propellant were discussed. The objective of this work was to discuss how to define the best parameter value based on the obtained results, and thus generate optimized formulations.

Resorcinol-formaldehyde (RF) organic gels have been extensively used to produce carbon aerogels. The organic gel synthesis parameters greatly affect the structure of the resulting aerogel. In this study, the influence of the catalyst quantity on the polymeric solution sol-gel process was investigated. Sodium carbonate was used as a basic catalyst. RF gels were synthesized with a resorcinol to formaldehyde molar ratio of 0.5, a resorcinol to catalyst (R/C) molar ratio equal to 50 or 300, and a resorcinol to solvent ratio of 0.1 g mL-1. The sol-gel process was evaluated in situ by Fourier transform infrared spectroscopy using a universal attenuated total reflectance sensor and measurements of the kinematic viscosity. The techniques showed the evolution of the sol-gel process, and the results showed that the lower catalyst quantity induced a higher gel point, with a lower viscosity at the gel point. Differential scanning calorimetry was used to investigate the thermal behavior of the RF dried gel, and results showed that the exothermic event related to the curing process was shifted to higher temperatures for solutions containing higher R/C ratios.

The need for new materials to substitute injured or damaged parts of the human body has led scientists of different areas to the investigation of bioceramics since the 70's, when other materials in use started to show implantation problems. Bioceramics show some advantages like being the material that best mimics the bone tissue but also, present low mechanical strength due to its ceramic nature. This paper presents a general view about the topic.