Soy-castor oil based polyurethanes with octaphenylsilsesquioxanetetraol double-decker silsesquioxane in the main chains

Abstract

An environmentally friendly, solvent-free/catalyst-free method was used to prepare soy-castor oil based polyols (SCPs) from epoxy soybean oil and castor oil. Thereafter, a series of hybrid polyurethanes using SCPs as feedstocks were synthesized with the introduction of double-decker silsesquioxane. Double-decker octaphenylsilsesquioxanetetraol (DDSQ) was prepared and characterized by ¹H NMR and MALDI-TOF-MS. Meanwhile, the soy-castor oil based polyols (SCPs) were also characterized by ¹H NMR and FTIR. Other characterizations such as DMA, TGA, SEM, FTIR, XRD, static contact angle and tensile test techniques were also applied to investigate the structures and properties of the hybrid polyurethanes. ¹H NMR spectra indicated that DDSQ was accessed in the form of chemical bonding sealing on polyurethane pre-polymers. DMA analysis demonstrated that the hybrid polyurethanes with DDSQ displayed enhanced glass transition temperatures (T_g) compared to the pure polyurethanes. The DDSQ-containing hybrid polyurethanes exhibited improved thermal stability in terms of thermogravimetric analysis (TGA). SEM revealed that both nano- and micro-sized DDSQ aggregates were shown to be dispersed heterogeneously in the polyurethane matrix. The results of XRD showed that DDSQ formed a nanocrystalline phase in any of the PUs. With the inclusion of DDSQ, the hydrophobicity of the hybrid material was significantly improved, as the results of the static contact angles revealed.