Studies on segmental hydrophilic/hydrophobic polyurethanes for biomedical applications

In this study, the polyurethane were prepared from 4,4′-diphenyl methane diisocyanate (MDI) and various molecular weights of polyols, including poly(dimethyl siloxane) (PDMS), poly(tetramethylene oxide) (PTMO), poly(propylene glycol) (PPG), poly(ethylene glycol) (PEG) of different molecular weights, and use 1,4-Butanediol(1,4-BD) as chain extender. The physical properties were determined by Fourier transformation infrared spectrophotometer (FTIR), stress-strain test, swelling ratio, solid-state nuclear magnetic resonance spectrometer (NMR), gel permeation chromatographer (GPC). The thermal properties were investigated by thermo-gravimetric analysis (TGA), differential scanning colorimeter (DSC), and dynamic mechanical analysis (DMA). The blood compatibility is determined by relative index of platelet adhesion (RIPA). Phase separation of the resulting polyurethanes occurs during polymerization because of the immiscibility of polyols. The phase separation of hydrophilic/hydrophobic structure changes surface tension and constitutes the hydrophilic phases and the hydrophilic phases of the polyurethane, respectively. It reduces the adhesion of blood platelet on the materials. The results from this study showed that the polyurethane synthesized with PDMS of molecular weight 1800 and PTMO of molecular weight 1000 at the ratio 50/50 is suitable for biomedical application as a blood-compatible material.