Biodegradable poly(L‐lactic acid)/TiO₂ nanocomposites: Thermal properties and degradation

Abstract

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 1N NaOH, enzymatically in a-amylase solutions, and under UV irradiation. The catalytic effect of TiO 2 nano particles on the degradation processes under UV light exposure (k ¼ 365 nm) and hydrolytic degradation was confirmed with the increase of the filler content. The opposite effect was identified in enzymatic degradation experiments.

Effect of the talc filler on structural, water vapor barrier and mechanical properties of poly(lactic acid) composites

“…Moreover, at short-time exposure (50 h) the weight loss determined for all composites is lower than 1%, while for neat PLA it is 3%. In our previous studies, it was shown that the photodegradation of PLA is significantly influenced by the addition of various nanofillers, for example TiO 2 [36,37]. The stability of all talc filled samples towards UV light is certainly due to the crystalline structure induced by the presence of talc in the PLA matrix and to the photodegradation inactivity of the filler itself.…”

Effect of TiO2 nanoparticle loading on Poly(l-lactic acid) porous scaffolds fabricated by TIPS

“…This result shows that crystallization of PLA (both primary and secondary crystallization) was completed during scaffold fabrication. The degree of crystallinity (χ c ,Table 2), calculated from the DSC curves by means of Equation increases with increasing content of TiO 2 nanoparticles in the scaffold, possibly due to an earlier reported nucleating effect of titania on PLA crystallization[27][28][29].XRD patterns of PLA and of its nanocomposite scaffolds, with distinctive crystalline peaks, are given inFigure 2. It can be observed that XRD pattern for pure PLA scaffold shows an intensive reflection at 2θ = 16.6° and a less intense peak at 2θ = 19.0°,corresponding respectively to the (110/200) and (203/113) planes of the orthorombic lattice of the α-form [30].…”

Data on Specific Polymers

“…587 Nanoparticles increased the degradation rate of polymer on UV exposure (365 nm). 587 Hydrolytic degradation rate was also increased with the filler content increased. 587 The enzymatic degradation was slowed down by the presence of nanofiller.…”

“…587 Presence of titanium dioxide and its concentration had little influence on glass transition and melting temperatures of polymer but it influenced the degree of crystallinity. 587 Nanoparticles increased the degradation rate of polymer on UV exposure (365 nm). 587 Hydrolytic degradation rate was also increased with the filler content increased.…”