Synthesis and characterization of hydroxy-terminated polyether-polydimethylsiloxane-polyether (PE-PDMS-PE) triblock oligomers and their use in the preparation of thermoplastic polyurethanes

A series of hydroxy-terminated polyether-polydimethylsiloxane-polyether (α,ω-dihydroxy-(PE-PDMS-PE)) ABA triblock oligomers were synthesized from silanic fluids and methyl polyallyloxide polyethers. The reaction was a one-step solventless hydrosilylation reaction with chloroplatinic acid (CPA) catalyst in the presence of heat. These ABA oligomers were characterized via 1H-NMR, 13C-NMR, 29Si-NMR, FT-IR, and GPC to demonstrate that they exhibit a 100% linear ABA structure with a siloxane SiO chain in the center and polyether ethylene oxide (EO)/propylene oxide (PO) chains on the two sides terminated by hydroxy groups. The triblock oligomers were used to form thermoplastic polyurethanes (TPUs) using two-step solventless bulk polymerization. The investigation of triblock oligomers impact on TPUs mechanical properties, thermal performance, surface water repellency, and morphology performance were analyzed by Instron material tester, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), water contact angles (WCA), scanning electron microscope (SEM), and transmission electron microscope (TEM). DSC and TGA indicated that PE-PDMS-PE modified TPUs had a clear lower Tg under −120°C and the temperature of 50% weight loss was improved from 280 to 340°C. PE-PDMS-PE–modified TPU did not have the marked reduction on mechanical properties than pure polyether produced TPU. Tensile strength was maintained at 13 MPa and elongation was maintained at 300%. SEM and TEM were used to investigate the copolymers’ morphology performance and found that all PO PE-PDMS-PE had a pseudo-three phase separation. WCA analysis confirmed that PE-PDMS-PE–modified TPU had significantly improved hydrophobic performance because the silicone structure linked into TPU copolymers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42521.