Compósitos ternários de poliuretano-TiO2-SiO2 : preparação, caracterização e degradação

Abstract

The addition of inorganic fillers in polyurethane resins for use as coating has been of great technological interest because it leads to improvements in the properties and performance of existing materials, besides the possibility of reducing environmental impact and costs. In this context, this work presents the production of ternary composites with addition of commercial inorganics fillers, titanium dioxide (TiO2) and silica (SiO2), in aqueous polyurethane dispersions. These ternary composites were obtained from the addition of 1% of different combinations of proportion of fillers (TiO2: SiO2 = 0:100 25:75 50:50 75:25 to 100:0) in aqueous polyurethane dispersions (PUD) by the in situ polymerization process. The characteristics of the ternary composite were evaluated in the form of polymer dispersion (particle size, pH, viscosity and conductivity) and in the form of films (thermal, mechanical and morphological properties), as well as the study of degradation of these materials. The results show that the synergy resulting from the combination of the two fillers, SiO2 and TiO2, interferes with the formation of micelles in PUD colloidal system, changing the coalescence process in the formation of films and modifying light reflection and refraction in the composite making it opaque and matte. The presence of anatase crystalline phase in TiO2 particles provides better compatibility filler1-filler2-polymer increasing the tensile strength and thermal stability of the ternary composites. The presence of SiO2 retarded the degradation process in the soil of the ternary composites and they did not show biological material on the surface after degradation.