Silanes, as coupling agents

Kokta, B.V., Maldas D., Daneault C., Beland P. Composites of poly(vinyl chloride) - wood fibers. Ill Effect of silane as coupling agent. Journal of Vinyl Technology 12(3) 146-53 (1990). 

Scheme 1. Silane as coupling agent between resin and liber.

Adhesion between polymer systems and mineral surfaces is significantly increased when using silanes as coupling agents (Fig. 7). The chemical bond on the mineral surface leads to superior adhesion and thus moisture and temperature resistance. The perfect bonding is exemplified in Fig. 8, showing a glass sphere in a polymeric matrix before (left) and after silane treatment. 

Condensation of Silanols on s Mineral Surface. . yields a t Fig. 7. Silanes as coupling agents between inorganic and organic matter. 

Park C, Lowther SE, Smith JG Jr, Connell JW, Hergenrother PM, St. Clair TL (2000) Polyimide-silica hybrids containing novel phenylethynyl imide silanes as coupling agents for surface-treated titanium alloy. Int J Adhes Adhes 20 457... 

Analog-to-glass fibers silanes are used as coupling agents for natural fiber polymer composites. For example, the treatment of wood fibers with product A-175 improves wood dimensional stability [53]. In contrast, a decrease of mechanical properties was observed for coir-UP composites after a fiber modification with di-chloromethylvinyl silane [54]. The treatment of mercer-... 

Aliphatic organofunctional silanes recommended as coupling agents for glass-reinforced polyesters, epoxies, or phenolics have heat stabilities of typical aliphatic organic chemicals and are not at all comparable to the methyl or phenyl silicones found in silicone polymers and resins. 

In this review, we will briefly discuss selected literature on hydrolysis and condensation reactions at silicon which are relevant to organofunctional silanes. Some studies will involve simpler (lower functionality) models some may involve related chemical reaction classes illustrating a mechanistic point. We will then discuss selected references focused on silanes of the types used as coupling agents and crosslinkers. Finally, some reactions at the interface will be mentioned. 

This modification is connected with a reversed use of the silane (siloxane) coupling agents. On the other hand, the hydrosilylation reaction is commonly applied as a method of crosslinking organic polymers containing vinyl and allyl groups with siloxanes and polysiloxanes with Si-H functionality (e. g., [27]). 

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