Preparation and properties of nanocomposites based on poly(lactic acid) and functionalized TiO2

Inorganic/polymer nanocomposites are significant materials due to their unique combination of properties. Lactic acid (LA) was used to modify the TiO2 surface by the Ti-carboxylic coordination bonds, and LA can chemically bond TiO2 nanoparticles to form functionalized oligomeric-poly(lactic acid)-grafted TiO2 nanoparticles (g-TiO2). The resulting g-TiO2 was added to the poly(lactic acid) (PLA) matrix to prepare PLA/TiO2 nanocomposites via melting processing. The structure and properties of the nanocomposites were subsequently investigated via Fourier transform infrared spectroscopy, gel permeation chromatography, scanning electron microscopy, transmission electron microscopy, polar optical microscopy, differential scanning calorimetry, dynamic rheometer and universal testing machine. The results showed that g-TiO2 nanocomposites had a much lower degree of agglomeration than bare TiO2. The introduction of g-TiO2 into PLA matrix improved the crystallinity of the composites. The functionalized nanoparticles played an important role in improving mechanical properties and reducing the complex viscosity of the nanocomposites due to its unique structure and the reasonable interfacial interaction between the nanoparticles and PLA matrix.