Gelest, Inc. has new line of dipodal silanes that function as adhesion promoters. They have intrinsic hydrolytic stabilities the company claims are far greater than conventional silanes, extending coating service life. They have achieved commercial success in applications such as adhesive primers for ferrous and nonferrous metals, and as adhesion promoters for multilayer laminates. “Dipodal silanes offer significant performance advantages over conventional silanes,” says Greg Hertenberger, Gelest product manager – silanes and metal-organics. “They can also be used in tandem with conventional silanes to create a synergistic blend that enhances overall performance. Depending on the system formulation, a mixture of just 10 percent dipodal silane amplifies the performance of conventional silanes and significantly increases adhesion promotion.” The silane coupling agent resists deterioration by the intrusion of water between the polymer and the substrate. In addition to providing water resistance, dipodal silane coupling agents increase the crosslink density and hardness of films. Cyclic azasilanes have greater reactivity than conventional alkoxysilanes.  They react rapidly with all surface hydroxyl groups, for efficient surface modification. “This recent class of silane coupling agents affords a smooth monolayer and reacts with substrates without forming such byproducts as alcohol, HCl, and cage-like condensation products typical with the use of conventional silane coupling agents,” added Hertenberger. Cyclic azasilanes reduce the overall waste stream as there are no longer any hazardous byproducts. Key applications include nanoparticle vapor-phase functionalization and capping of silanol functional siloxanes.