Study on the non-isothermal crystallization behaviors of PA6/silica nanocomposites prepared by the sol-gel process

A organic-inorganic PA6/partially functionalized silica hybrid nanocomposites was prepared by caprolactam polymerized and silica nanoparticles in situ gernerated through condensation of partially functionalized silicic acid, which was prepared through hydrolysis of tetraethoxysilane (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTES), in one process. The non-isothermal crystallization behaviors of pure PA6, PA6/unfunctionalized silica (PA6S) and PA6/functionalized silica (PA6FS) hybrid materials were investigated by differential scanning calorimetry (DSC). Two methods, namely, the Avrami and the Mo, were applied to describe the crystallization process of these three materials. DSC results showed that the crystallization rates of PA6FS is faster than that of pure PA6 and PA6S at the same cooling rate, the nano-silica particles functionalized by GPS in hybrid material acted as more effective nucleation agents, and the crystallization rates of all these samples increased with the cooling rate increasing. XRD results indicated that the addition of functionalized nano-silica particles favored the formation of the gamma crystalline form.