Abstract:The preparation of TiO₂/poly(L-lactide-co-ε-caprolactone) (PLCL) nanocomposites and their properties were reported. TiO₂ nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone (ε-CL). The resulting poly(ε-caprolactone)-grafted TiO₂ (g-TiO₂) was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The g-TiO₂ can be uniformly dispersed in chloroform and the g-TiO₂/PLCL nanocomposites were successfully fabricated through solvent-casting method. The effects of the content of g-TiO₂ nanoparticles on tensile properties and shape memory properties were investigated. A significant improvement in the tensile properties of the 5% g-TiO₂/PLCL mass fraction nanocomposite is obtained: an increase of 113% in the tensile strength and an increase of 11% in the elongation at break over pure PLCL polymer. The g-TiO₂/PLCL nanocomposites with a certain amount of g-TiO₂ content have better shape memory properties than pure PLCL polymer. The g-TiO₂ nanoparticles play an additional physical crosslinks which are contributed to improvement of the shape memory properties.

Key words: poly(L-lactide-co-ε-caprolactone); nanocomposites; TiO₂ nanoparticles; surface grafting; shape memory properties; mechanical properties