Polyurethane with tris(trimethylsiloxy)silyl propyl as the side chains: Synthesis and properties

Two kinds of diols (MI and MII) and a triol (MIII) with tris(trimethylsiloxy)silyl propyl as the side chains were designed and synthesized. Then three series of silicone modified polyurethanes (SPUI-III) prepolymers were prepared from MI-III, polyether triol (N307) and dicyclohexylmethylmethane-4, 4′-diisocyanate (HMDI). Their structures were confirmed by 1H NMR, 13C NMR and FTIR analysis. Then SPUI-III films were obtained by the moisture curing of the polyurethanes prepolymers, and their properties were investigated by Attenuated total reflection flourier transformed infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), water surface contact angle (WCA), water and ethanol absorption ratio, stress-strain, abrasion resistance and X-ray diffraction (XRD) analysis. It has been demonstrated that easier surface migration of side-chain silicone segments means only 10 wt% of MI-III can improve the surface hydrophobicity and smoothness, water resistance and abrasion resistance of SPU significantly. Meanwhile, the balance between the polar groups in the backbones and the nonpolar silicone oligomers in the side chains of MI-III is a key to control solubility, compatibility, migration and phase separation with polyurethane system. And difference in structures and dosages of MI-III can influence the abrasion resistance properties, microphase separation, thermal and tensile properties of the prepared SPU materials. Low loadings (10 wt%) of MI-III make remarkable abrasion resistance and excessive loadings make subdued abrasion resistance. Interestingly, the special microphase separation patterns could be obtained in SPUIII series with a proper MIII loading (10–20 wt %).