Desenvolvimento e validação de um sistema de jateamento com cerâmicas bioativas para a modificação de superfície de poliamida e de policarbonato

Abstract

The use of polymeric implants presents advantages, as long as the surface is functionalized to ensure osseointegration. A new low-cost surface modification technique for inserting hydroxyapatite and titanium dioxide into polyamide and polycarbonate was investigated in this work. A blasting system with intermittent compressed air and continuous hot air was developed and tested, whose process parameters could be controlled and measured by Arduino platform and compatible sensors. The chemical characterization confirmed a crystalline structure of nanometric order of the particulates used, for which the osseoinductive properties are highly recognized. The polymer characterization techniques indicated the crystallization and glass transition temperatures, which based the adjustment of the process parameters and explained many of the observed phenomena. The experimental design of fractional factorial type allowed the study of the influence of the polymer and its roughness, particulate, pressure, time and intermittency of compressed air on the output variables. The internal and external temperature of the polymer, chemical composition of the surface, topography and roughness, mass variation, hardness and microhardness were measured and analysed. Good adhesion was observed for ceramic particles, which could be found evenly on all blasted surfaces even after cleaning by ultrasound. The topographical appearance varied between the tests and also within each sample, with the presence of several macrographic defects in many of them, but with better regularity for polyamide. The bubbles, porosities and deformations caused great variations in the hardness of the material, and were observed in the samples submitted to the highest and average temperatures. The results indicate the need to optimize the process by adjusting the input variables in order to combine the deposition efficiency of the bioactive layer, already verified in the tests and pre-tests, with the maintenance or improvement of the substrate's mechanical properties.