Los polímeros conductores de la electricidad y sus aplicaciones en la nanotecnología

A polymer is a molecule, natural or synthetic, that consists essentially of repeated identical structural units. One of the most attractive properties of the classic organic polymers has been their ability to act as excellent electric insulators. Nevertheless, a great interest has existed in the possibility of producing polymers that act like electrical conductors. These new materials, denominated conducting polymers, could change the electrical and electronic industry by combining excellent mechanical and chemical properties, besides their easy preparation and low cost of manufacture. In this work, a short review is done about the main characteristics of conducting polymers and their synthesis by microemulsion polymerization due to its importance and a great potential to be used industrially in medicine, electronic and some biological applications.Un polímero es una molécula, natural o sintética, que consiste esencialmente en unidades estructurales idénticas repetidas. Una de las propiedades más atractivas de los polímeros orgánicos clásicos ha sido la capacidad de actuar como excelentes aislantes eléctricos. Sin embargo, ha existido un gran interés en la posibilidad de producir polímeros que actúen como conductores eléctricos. Estos nuevos materiales, a los que se han denominado polímeros conductores, podrían revolucionar la industria eléctrica y electrónica al combinar excelentes propiedades mecánicas y químicas, además de su fácil preparación y bajo costo de fabricación. En este trabajo, se hace una revisión sobre las principales características de los polímeros conductores y su síntesis mediante un método relativamente nuevo llamado polimerización en microemulsión ya que existe un potencial para ser utilizados industrialmente, en medicina, electrónica y en otras aplicaciones biológicas

Impact Evaluation of High Energy Ball Milling Homogenization Process in the Phase Distribution of Hydroxyapatite-Barium Titanate Plasma Spray Biocoating

Air plasma spray technique (APS) is widely used in the biomedical industry for the development of HA-based biocoatings. The present study focuses on the influence of powder homogenization treatment by high-energy ball milling (HEBM) in developing a novel hydroxyapatite-barium titanate (HA/BT) composite coating deposited by APS; in order to compare the impact of the milling process, powders were homogenized by mechanical stirring homogenization (MSH) too. For the two-homogenization process, three weight percent ratios were studied; 10%, 30%, and 50% w/w of BT in the HA matrix. The phase and crystallite size were analyzed by X-ray diffraction patterns (XRD); the BT-phase distribution in the coating was analyzed by backscattered electron image (BSE) with a scanning electron microscope (SEM); the energy-dispersive X-ray spectroscopy (EDS) analysis was used to determinate the Ca/P molar ratio of the coatings, the degree of adhesion (bonding strength) of coatings was determinate by pull-out test according to ASTM C633, and finally the nanomechanical properties was determinate by nanoindentation. In the results, the HEBM powder processing shows better efficiency in phase distribution, being the 30% (w/w) of BT in HA matrix that promotes the best bonding strength performance and failure type conduct (cohesive-type), on the other hand HEBM powder treatment promotes a slightly greater crystal phase stability and crystal shrank conduct against MSH; the HEBM promotes a better behavior in the nanomechanical properties of (i) adhesive strength, (ii) cohesive/adhesive failure-type, (iii) stiffness, (iv) elastic modulus, and (v) hardness properties

The Use of Recycled PET for the Synthesis of New Mechanically Improved PVP Composite Nanofibers

Polyethylene terephthalate (PET) waste has become a major challenge for the conservation of the environment due to difficult degradation. For this reason, it is important to develop new recycling strategies for reusing this waste. In this work, the electrospinning technique was used to synthesize composite nanofibers of polyvinylpyrrolidone (PVP), recycling PET (RPET) that was obtained from the chemical recycling of postconsumer PET with glycolysis and styrene (ST) as a crosslinking agent. The polymer solutions were analyzed by viscosity and frequency sweeping, while the composite nanofibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and nanoindentation to compare their properties. The PVP nanofibers presented an average diameter of 257 nm; the RPET/PVP and RPET/PVP/ST composite nanofibers had average diameters of 361 nm and 394 nm, respectively; and the modulus of elasticity and hardness of the RPET/PVP/ST composite nanofibers were 29 and 20 times larger, respectively, than those of the PVP nanofibers. With the synthesis of these composite nanofibers, a new approach to PET recycling is presented