Synthesis of hydroxyl silane coupling agent and its application in preparation of silane‐modified polyurethane

Abstract This study describes the synthesis of a hydroxyl silane coupling agent (HO‐silane) through a click reaction between SH in 3‐(trimethoxysilyl)propane‐1‐thiol (KH‐590) and CC in 2‐hydroxyethyl methacrylate (HEMA). This coupling agent was subsequently employed in the synthesis of silane‐modified polyurethane (SPU) resin which could be moisture‐cured at room temperature. The influence of r values (the molar ratio of  NCO and  OH) on the characteristics of SPU resins was investigated. These results reveal that an increase in the r value leads to a reduction in viscosity from 4.9 × 10 5 to 1.9 × 10 5 mPa·s, a rise in tensile strength from 0.88 to 0.98 Mpa followed by a decline to 0.69 MPa, and a reduction in extension at fracture from 236% to 94%. A SPU resin with a viscosity of approximately 3.6 × 10 5 mPa·s, tensile strength of 0.98 MPa, and elongation at break of 218% can be produced when the r value is 1.8. In addition, a silane‐modified polyurethane (MS) sealant with a tensile strength of 1.6 MPa in addition to elongation at break at 336% could be produced using the aforementioned SPU resin.