1.3 Organosilane [66] Monomeric silicon chemicals are known as silanes and any chemical that contains at least one carbon-silicon bond is known as an organosilane. Generally, organosilanes contain three key elements beside silicon; X represents for an organic moiety that is non-hydrolysable which can be either reactive or non-reactive depending on its type. OR\ is a hydrolysable group such as alkoxy or an acetoxy is known to be unstable when present with hydroxyl groups. Finally, R is a space moiety, which can be aryl or alkyl chain. Typically, due to the dual reactivity of organosilane, both alkoxy group (OR\) and non-hydrolysable organic moiety (X), it is used to couple inorganic or organic substrates such as minerals, metals or cellulose and polymeric matrices such as rubber, thermoplastic or thermosets to improve its physical properties. The applications include adhesion promoter, dispersing/hydrophobing agent and crosslinking agent. 1.3.1 Adhesion Promoter Organosilanes are effective adhesion promoters when used as integral additives or primers for paints, inks, coatings, adhesives and sealants. As integral additives, they must migrate to the interface between …show more content…
Each exhibits unique chemical reactivity. These molecules will react with atmospheric moisture or water adsorbed on a surface to form silanols, while liberation of the corresponding by-product will occur (e.g., HCl, NH3, alcohol or carboxylic acid). These silanols can then react with other silanols to form a stable siloxane bond (-Si-O-Si-). In the presence of hydroxyl groups at the surface of glass, minerals or metals (e.g., aluminum, steel), silanols will form a stable M–O-Si bond (M = Si, Al, Fe, etc.). This is the key chemistry that allows silanes to function as valuable surface-treating or “coupling”