Preparation and characteristics of polyurethane-based composites reinforced with bioactive ceramics

The purpose of the study was to synthesize and characterize a series of porous polyurethane-based composites modified with β-tricalcium phosphate (TCP) and hydroxyapatite (HAp). The composites were obtained by the one-step bulk polyaddition method using poly(ethylene glycol) (PEG) as a soft segment, 4,4’-diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO) as a chain extender and selected bioactive bioceramics. The obtained composites were characterized using FTIR, DSC, TG and SEM/EDX methods. Moreover, in vitro chemical stability and wettability tests were performed. The preliminary assessment of mechanical properties, porosity and in vitro chemical stability was performed. The test results showed that the best pore distributions, as well as Young’s modulus, were found for the hydroxyapatite--modified composites and PU/20% TCP. The wettability investigations revealed that the contact angle of PU composites was in the range 50-80°, which indicates the hydrophobic nature of the materials. The in vitro biostability studies confirmed that all tested compo-sites were chemically stable during incubation in the simulated body fluid. By using infrared spectroscopy the presence of urethane bonds and completion of reaction were evidenced. The results showed that the bioactivity of the materials was improved, which makes good perspectives for the obtained materials to be considered as potential scaffolds in bone tissue regeneration.