Caracterizações físico-químicas e de viabilidade celular de uma nova poliuretana à base de Policaprolactona-diol e Trimetileno Carbonato

Abstract

Among the polymers widely investigated as materials for tissue engineering, polyurethane is very prominent. The need for devices with certain mechanical properties combined with the ability to be biodegradable and bioresorbable has been motivating the scientific community to find new biomaterials. This study aimed to synthesize, characterize and analyze the biological viability of a polyurethane based on Polycaprolatone-diol (PCL-diol) and Trimethylene Carbonate (TMC). The synthesis combined the mechanical properties present in Polyurethane and PCL, with increased elasticity due to the use of TMC. The synthesis of the prepolymer occurred via bulk polymerization between PCL-diol and TMC with a 50/50 mass ratio, using the SnOct2 catalyst. The GPC analysis of the prepolymer showed the Mn, the Mw and the PI between, respectively, 8,173 and 8,727 g.mol-1, 13,898 and 15,399 g.mol-1, 1.68 and 1.83. The formation of poly(PCL-TMC)urethane occurred via solution polymerization between the prepolymer and HDI, using the solvent 1,2-dichloroethane and a 1 : 2 molar ratio (prepolymer / HDI). The synthesis of prepolymer and polyurethane was confirmed by FTIR and 1H NMR. Using ASTM D882-02, the material was subjected to a mechanical tensile test showing the following results, elongation of 983.03 ± 289.20%, elastic modulus of 2.62 ± 0.17 Mpa and maximum stress of 0.61 ± 0.09 Mpa, demonstrating the elastomeric property of the material. DSC and TG techniques thermally characterized the synthesized polymer. The melting temperature was not observed in the DSC curve, indicating that the copolymer is amorphous, and the Tg found was -39.00 ºC. TG showed Tonset and Td, respectively 269.00 ºC and 288.00 ºC. The average value of contact angle found of 88.00° ± 1.96° showed that the material does not exhibit high hydrophilicity. The rheology study demonstrated the pseudoplastic characteristic of polyurethane and a low complex viscosity. No mass loss was observed in in vitro degradation for 48 weeks. The biocompatibility essay showed a small decrease in the number of mesenchimal stem cells on the day 1 after cell culture, but after 7 days the cells showed growth and adhesion compatible with the controls. The results demonstrating potential of the material in applications where elastomeric properties are required such as meniscus prostheses, cardiac devices etc.