Síntese e caracterização de filmes biodegradáveis de poliuretano baseados em hexametileno diisocianato e métodos de tratamento para aumento da bioatividade

Abstract

Synthetic biodegradable polymers are considered strategic in tissue engineering and are used in various applications. Among the biopolymers used as biomaterials, polyurethanes (PU) feature prominently, due to its versatility, being possible to obtain products with a wide range of physical and mechanical properties. The incorporation of bioceramics and surface treatment of these polymers with bioactive materials has proven effective in the improvement of their properties. Considering the great potential of polyurethanes, this study proposed the synthesis and characterization of polyurethane films, for potential application in tissue engineering, and the study of methods to enhance their bioactive character. Various polyurethanes compositions were synthesized based on HDI, PCL triol, PEG and glycerol. Hydrophilic, transparent and flexible films were obtained. Analyses of infrared spectroscopy (FTIR) confirmed the presence of typical polyurethane bands, while the analysis of X-ray diffraction (XRD) showed the amorphous nature of the polymers. The thermal analysis (TG and DSC) confirmed the high degree of mixing of the hard and soft segments of polyurethane, due to the high content of crosslinked bonds. The degradation studies demonstrated the susceptibility of the films to undergo hydrolytic degradation. Bioactive glass nanoparticles were synthesized by the modified Stöber method, and incorporated into polymeric films by ultrasonic process. This process influenced the degradation rate of the material in PBS and changed their mechanical properties, reaching a deformation of up to 889,3%, elasticity modulus of 1,6MPa and tensile strength of 5,4MPa. The films were treated with concentrated SBF solution, which led to the deposition of a layer of calcium phosphate on their surface, increasing the bioactivity of the material. The materials obtained showed no toxic effects by MTT cytotoxicity assays, being promising materials for use as biomaterials.