Used as a coupling agent in composite materials to improve adhesion between organic polymers and inorganic surfaces, especially in rubber-reinforced silica systems. Enhances mechanical strength and durability in tires and rubber products. Also applied in surface modification of glass, metals, and fillers to introduce thiol (-SH) groups for further chemical functionalization. Commonly used in coatings, adhesives, and sealants to promote crosslinking and improve moisture resistance.