Relaxation dynamics in plasticized polylactide
Résumé
Polylactide has been plasticized with acetyl tributyl citrate at several degrees (0 to 13%), leading to a modification of the Van der Waals interactions between the macromolecules without damaging the covalent bonding. The decrease of the dynamic glass transition temperature with plasticizer content has been recorded from calorimetric measurements and dielectric relaxation spectroscopy. It is shown that the supplementary free volume brought by the plasticizer enhances molecular mobility and induces a concomitant decrease of the cooperativity length with the decrease of the activation energy.