Coupling agents usually improve the degree of crosslinking at the interface.
Silane coupling agents are effective in modifying the natural fi ber–matrix
interface. Silanols form in the presence of moisture and hydrolyzable
alkoxy groups and react with the cellulose hydroxyl group of the fi ber,
improving fi ber–matrix adhesion and stabilizing the composite properties
(Bledzki et al ., 2008 ). Coupling agents such as toluene diisocyanate and
triethoxyvinylsilane have been tested in fi ber treatment processes in
order to improve the interfacial properties. Silanes undergo hydrolysis,
condensation and a bond formation stage. Silanols can form polysiloxane
structures by reaction with the hydroxyl group of the fi bers