Tool Box Dow Corning（工具箱道康宁）.pdf

Tips Tool Box Tips Tool Box A Summary of Silanes Silane Coupling Agents Silane coupling agents are silicon-based chemicals that contain two types of reactivity – inorganic and organic – in the same molecule. A silane coupling agent will act as an interface between an inorganic substrate (such as glass, metal or mineral) and an organic material (such as an organic polymer, coating or adhesive) to bond, or couple, the two dissimilar materials. Why Silane Coupling Agents Are Used When organic polymers are reinforced with glass fibers or minerals, the interphase region between the polymer and the inorganic substrate is involved in a complex interplay of physical and chemical factors. Silane coupling agents have the unique chemical and physical properties not only to enhance bond strength but also, and more importantly, to prevent de-bonding between the polymer and the substrate during composite aging and use. Benefits silane coupling agents can provide include: • A substantial increase in flexural strength • Increased bond strength of coatings and adhesives • Increased resistance to humidity and other adverse environmental conditions • Better wetting of inorganic substrates • Lower viscosities during compounding • Smoother surfaces of composites • Less catalyst inhibition of thermoset composites • Clearer reinforced plastics The Silane Bond to the Inorganic Substrate Silane coupling agents that contain three inorganic reactive groups on silicon (usually methoxy, ethoxy or acetoxy) will bond well to the metal hydroxyl groups on most inorganic substrates, especially if the substrate contains silicon, aluminum or a heavy metal. The alkoxy groups on silicon hydrolyze to silanols, either through the add