6533b858fe1ef96bd12b5fba

RESEARCH PRODUCT

Effects of phenolic-like intercalated layered double hydroxides on poly(lactic acid) based nanocomposites

subject

description

Two phenolic-like antioxidants (AOs), 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate and 6-hydroxy-2,5,7,8-tetrametilcromano-2-carboxylate anions, were intercalated by anion exchange in layered double hydroxides (LDHs). The two AO-LDHs were dispersed by ultrasound-assisted solution mixing in poly(lactic acid) (PLA) and the thermal oxidation stability of the composites was evaluated following the variation of the molecular weight by SEC, after a controlled aging process, and determining the oxidation induction time (OIT) by DSC. The results evidenced that the intercalation of both the AO molecules within the LDH galleries prevent their own thermal and thermo-oxidative degradation as well as the thermo-oxidative degradation of PLA. Interestingly, it was also found a correlation between the morphology of the AO-LDH/PLA nanocomposites and their thermal oxidation resistance. An advantage of the AO confinement between the LDH galleries is the reduction or hindrance of the AO migration, when the hybrid filler is added to a polymer matrix. In this way the oxidation stability of the composites is prolonged.