Preparation and properties of siloxane modified polyurea materials

This work aimed to enhance polyurea’s mechanical properties, water resistance, and substrate adhesion through siloxane modification. Amino-terminated polyurea prepolymer was synthesized from hexamethylene diisocyanate (HDI) and polyaspartic acid ester resin F420, then modified with 3-aminopropyl-methyl-diethoxysilane (KH902) under optimized conditions (12-min prepolymerization; 4.35 wt% KH902). Structural and performance characterization via FTIR confirmed Si–O–Si integration (1050 cm −1 peak), while mechanical testing revealed exceptional tensile strength (54.75 MPa) and elongation (28.81%). The modified polyurea exhibited outstanding water resistance (1.52% absorption after 7 days; 95.87% tensile/94.94% elongation retention) and enhanced cement mortar adhesion (4.5 MPa). Thermal stability improved significantly, with TGA showing delayed degradation onset. These results demonstrate KH902-modified polyurea’s potential for demanding applications like infrastructure reinforcement.