Self-Healing Waterborne Polyurethane With Enhanced Mechanical Properties Based on Nano-Silica

Waterborne polyurethanes with self-healing damage and restore mechanical properties became widely used. The self-healing performance was closely related to good chain segment mobility, but loose chain segments could weaken mechanical properties. High mechanical performance and high self-healing performance were contradictory. Therefore, research on how to ensure high self-healing while improving the mechanical properties of materials became one of the research directions for self-healing materials. In this work, waterborne polyurethanes with disulfide bonds were first prepared, and then nano-silica was dispersed through mechanical stirring to obtain silica-modified self-healing waterborne polyurethane (SWPU-SiX). The effect of nano-silica content on the properties of SWPU-SiX were studied. It was found that the tensile strength of the prepared material reached 16.58 MPa, and the toughness reached 67.51 MJ/m 3 representing increases of 397.57% and 150.43% compared to SWPU, respectively. It could be almost completely healed at 80C. The enhancement of these properties provides a new method for the research of self-healing materials.