Development, characterization and numerical simulation of the effect of incorporating a compatibilizer on the properties of bio-sourced polymer blends

Abstract

This work focuses on the study of the structural, thermal, rheological, morphological and mechanical properties of PLA/PS and PLA/LDPE polymers using a compatibilising agent, SEBS-g-MAH, in different proportions. The aim was to better understand the role of SEBS-gMAH as a bonding agent between the two different blends. Theoretical calculation (simulation), in particular molecular modelling, was also used as an alternative to obtain results concerning structural and spectroscopic properties. Analysis, using X-ray difraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), confirmed a reduction in PLA crystallinity with the addition of SEBS-g-MAH in both types of blends. Theoretical calculations, in particular dynamic molecular MD, confirmed the increase in binding energy between PLA and PS and the role of SEBS-g-MAH in improving their compatibility. DFT results, including DOS and COSMO calculations, indicated an affinity between LDPE and the compatibiliser in the olefin part of SEBS-g-MAH. For PLA, an affinity was identified between the ester group (C=O) and the O-H group of SEBS-g-MAH. Keywords: polylactic acid, blend, compatibiliser, simulation, molecular modelling.