Showing papers by "José Luis de la Fuente published in 2019"
TL;DR: Different synthetic conditions were explored for the production of HCN polymers from NH4 CN or diaminomaleonitrile in aqueous media with different concentrations of the starting reactants and several reaction times, which resulted in a clear differentiation of their morphological and electrochemical properties.
Abstract: HCN polymers are a group of complex and heterogeneous substances that are widely known in the fields of astrobiology and prebiotic chemistry. In addition, they have recently received considerable attention as potential functional material coatings. However, the real nature and pathways of formation of HCN polymers remain open questions. It is well established that the tuning of macromolecular structures determines the properties and practical applications of a polymeric material. Herein, different synthetic conditions were explored for the production of HCN polymers from NH4 CN or diaminomaleonitrile in aqueous media with different concentrations of the starting reactants and several reaction times. By using a systematic methodology, both series of polymers were shown to exhibit similar, but not identical, spectroscopic and thermal fingerprints, which resulted in a clear differentiation of their morphological and electrochemical properties. New macrostructures are proposed for HCN polymers, and promising insights are discussed for prebiotic chemistry and materials science on the basis of the experimental results.
22 citations
TL;DR: In this article, the potential of zero total charge (PZTC) and cyclic voltammetry were measured at carbon-supported Ru@Pt core-shell catalysts, and it was shown that the lower PZTC cannot be explained exclusively by a lower free charge.
7 citations
01 Jan 2019
TL;DR: In this paper, the effects of the performance of ammonium perchlorate-based composite propellants by means of employing nanopowder transition metal oxides as BR catalysts in comparison with traditional microfillers, the most representative and active of which are iron(III) oxide and cupric oxide, are described.
Abstract: The use of different additives to modify the burning rate (BR) of composite solid propellants (CSPs) has been a topic of much study during decades within rocket motor technology. This perspective chapter initially describes the effects of the performance of ammonium perchlorate-based composite propellants by means of employing nanopowder transition metal oxides as BR catalysts in comparison with traditional microfillers, the most representative and active of which are iron(III) oxide and cupric oxide. In addition, titania represents a new generation of BR catalyst with great potential in this field. CSPs with microparticles as catalyst seem to be less stable due to oversensitivity to pressure variations, but the nanostructured propellants yield highly stable BRs over a broad pressure range. On the other hand, a brief review of surveys of recent progress on the synthesis, macrostructural characterization, and properties of metallo-polyurethanes, as well as their applications as advanced binders in the formulations of CSPs based on hydroxyl-terminated polybutadiene, is addressed. The incorporation of both metallic oxide nanoparticles and polymeric organocatalysts based on ferrocene in the formulations of these energetic materials could improve their ballistic and thermal combustion properties. The latter characterization was commonly done by thermal analytical techniques, such as thermogravimetry analysis and differential scanning calorimetry.
7 citations