Role of the plasticizers on the crystallization of PLA and its composites with mesoporous MCM-41

Abstract

Several materials were prepared by melt extrusion, based on an L-rich polylactide (PLA), as polymeric matrix, acetyl tri-n-butyl citrate (ATBC) or trioctyl trimellitate (TOTM), as plasticizer, and mesoporous MCM-41 particles, playing a nucleant role. Influence of the addition of these nucleating particles, together with the comparative effect of the two plasticizers, has been thoroughly evaluated on the features of the several phase transitions existing in the PLA polymeric matrix (glass transition, cold crystallization, α′ to α transition, melting processes and melt crystallization) as well as on the rate of PLA crystallization. The window where this ordering process can take place is shifted down to lower temperatures for these binary and ternary systems and the range of temperatures at which the α′ and α polymorphs crystallize under isothermal crystallization from the glassy state significantly changes in the materials containing ATBC as plasticizer, either the binary or ternary ones. Type of the major crystalline lattice developed at 85 and 110 °C has been confirmed, additionally to the DSC experiments, by FTIR spectroscopy.Graphical abstract