Resumen de Propiedades y comportamiento mecánico de nanocomposites de polisulfona ?-alumina biocompatible
Susana Anaya Perales
Polysulfone and ?-alumina are highly promising materials for bio sanitary applications where biocompatibility, strength and hardness are key issues, but neat ?-alumina degrades the polymer at the high temperatures involved in its processing (320-360ºC). It is thus necessary to find surface modification methods which, besides, should comply with the stringent biosanitary protocols for manufacturing parts in contact with the body. Using a green chemistry methodology, it is shown that natural fatty acids are good candidates; they form bridging bidentate complexes that separate the polymer matrix from the nanoparticles. Surprisingly, although weak particle-matrix interactions are presumed, an important enhancement of mechanical performance has been found. Electron microscopy reveals an extended region of influence of the particles which has been attributed to the crystallization of the fatty acids. Nanocrystals, experience high temperature phase transitions shifted about 150 ºC above their normal melting points and exclude the polymer originating a local compressive state in the matrix responsible for the properties enhancement. ,On the other hand, abrasive wear tests revealed that carboxylic acid-modified alumina nanocomposites exhibited better wear abrasive resistance as compared to bare alumina nanocomposite and neat PSF. Long chain fatty acids grafted to alumina protect polysulfone from a degrading effect, without sacrificing transparency.
