The role of segmental mixing on the mechanical properties and oxidative stability of polydimethylsiloxane-based polyetherurethane

Polydimethylsiloxane(PDMS) based segmented polyether urethanes (SiPEUs) suffer from poor adhesion between apolar PDMS and polar hard domains, which results in inferior mechanical properties and inadequate stability in long-term implantation. To regulate the interfacial miscibility, three chain extenders attached with different dangling side chains (fluorinated diol FDO, silicone-based diol SDO, and hexyl-based diol HDO) were used in two-step synthesis to modify the polarity of hard segments. Thermal analysis demonstrated a higher glass transition temperature of PDMS and PTMO (poly (tetramethylene oxide)) domain in SDO modified SiPEU (SSPEU) in contrast to the samples extended with FDO and HDO. Fourier transform infrared spectroscopy (FT-IR), small-angel x-ray scattering (SAXS), and dissipative particle dynamics (DPD) simulation further proved that SSPEU was achieved with optimal interfacial miscibility compared with SPEU. The intermediate layers were proposed to be functionally percolated composed of PDMS, PTMO, MDI-SDO, and MDI-BDO units, which pro-moted oxidative stability under accelerated test in vitro without mechanical compromise.

Automated summary

This study focuses on modifying the polarity of SiPEUs by using chain extenders with different dangling side chains, in order to improve their mechanical properties and stability in long-term implantation. The results show that the modified SiPEUs exhibit optimal interfacial miscibility, resulting in improved oxidative stability without sacrificing mechanical properties. This research provides valuable insights for developing biomedical materials with enhanced performance and stability.