Epitaxial nucleation, modulated structure of molecular aggregation, and enhanced thermal degradation temperature of poly(ethylene adipate): Effects of the naturally occurring uracil as a nucleator

Abstract

We fabricated a novel bio-composite using the poly(ethylene adipate) (PEA) and naturally occurring uracil (URA), in which the URA with the full biocompatibility and degradability acted as a nucleator (NA). A distinct enhancement was found in the crystallizability, melt-crystallization temperature (T c ), and crystallization rate of the PEA upon incorporation of the URA, an indicative of a good NA of the URA. The underlying nucleation mechanism of the PEA is the epitaxial nucleation, attributed to the extremely good matching between the crystal lattice of the PEA and URA. The H-bond interaction exists between the carbonyl/ester segment of the PEA crystalline phase and URA. With loading of the URA, both the carbonyl and ester fell behind the CH 2 in the segmental reorganization in the crystallization process of the PEA. The PEA/1%URA showed an enhancement in the T d in the TG measurement (i.e. increased stability in thermal degradation), mainly attributed to the flame retardance effect of the URA.