Vinyltrimethoxy Silane and Aminopropyl Triethoxysilane: Excellent Silane Coupling Agents for Cotton Fiber Functionalization

Vinyltrimethoxy silane and aminopropyl triethoxysilane were used for surface functionalization to enhance the textile performance of cotton. The process was carried out in an ethanol-water medium, which accelerated the cross-linking reaction between fiber and silane monomers. The process was optimized carefully as a function of fiber weight gain. The optimized modification conditions were silane monomer concentration 600 and 300% (on weight of fiber), ethanol-water ratio 60:40 and 80:20, pH 3.5 and 5, reaction time 90 and 60 min at room temperature (30°C), for VTMS and APTES, respectively. The silane-modified cotton fiber showed improved tensile strength, water repellency, thermal stability and wrinkle recovery. These improvements are due to flexibility of the Si-O bond and the fiber matrix interfacial strength properties. Instrumental analyses, such as FTIR, TGA, DTG, SEM and EDX, were carried out successfully. FTIR was used to identify the Si-O-Si group of VTMS and the Si-O-CH3 of APTES on modified cotton fibers, and TGA and DTG were used to evaluate the modification's effect on the thermal stability of the fiber. SEM was used to study the surface morphology after modification and EDX was used to measure the quantity of elemental silicon atoms on the fiber backbone. Finally, unmodified and silane-modified cotton fibers were dyed with two reactive dyes and the modified cotton fiber showed better ability to accept dye than that of the unmodified fiber.