Biodegradable poly( L ‐lactic acid)/TiO 2 nanocomposites: Thermal properties and degradation

Poly( L ‐lactic acid)‐titanium dioxide nanocomposites (with various loadings of TiO 2 : 0.5, 1, 2, 5, and 10 wt %) were produced by solution casting method. The influence of TiO 2 on thermal properties and crystallinity of PLA was investigated by DSC and FTIR spectroscopy. The TiO 2 nano filler has no significant influence on the characteristic temperatures ( T g , T c , and T m ), but has high impact on the crystallinity of these systems. The degree of crystallinity X c significantly increases for PLA nanocomposites loaded with up to 5 wt % of TiO 2 , while for 10 wt % load of TiO 2 it drops below X c of the pure resin. The degradation of the prepared composites was evaluated hydrolytically in 1 N NaOH, enzymatically in α‐amylase solutions, and under UV irradiation. The catalytic effect of TiO 2 nano particles on the degradation processes under UV light exposure (λ = 365 nm) and hydrolytic degradation was confirmed with the increase of the filler content. The opposite effect was identified in enzymatic degradation experiments. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012