Synthesis and microphase separated structures of polydimethylsiloxane/polycarbonate-based polyurethanes

Abstract

In this study, to obtain polycarbonate urethanes (PCU) with good mechanical properties and biostability, a series of polycarbonate urethanes containing various low levels of polydimethylsiloxane (PDMS) were synthesized via a two-step bulk polymerization using 4,4′-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) as the hard segment, and PDMS–poly(1,6-hexyl carbonate) diol (PHC) mixed macrodiols as the soft segment, where the content of PDMS was limited to less than 30 wt%. The resulting polyurethanes were fully characterized using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and mechanical tests. It was found that the incorporation of PDMS into the PCU enhanced the microphase separation and miscibility of PDMS with polar urethane hard segments. Moreover, these polyurethanes with higher molecular weights exhibit good mechanical properties, and are promising biostable polyurethane materials for long-term implant applications and interesting candidates for further investigation.