Effects of the poly(L-lactic acid)/poly(D-lactic acid) stereocomplex on crystallisation and morphology of poly(lactic acid) materials
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
Young Polymer Researchers Austria Meeting 2024
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
The self-nucleation effect of the equimolar poly(lactic acid) stereocomplex (SC-PLA) on the crystallisation behaviour and resulting morphology of poly(DL-lactide) (PDLLA) and poly(L-lactic acid) (PLLA) matrices may lead to an improvement in material properties, in particular increased performance, which would promote the use of PLA as a bio-based and sustainable polymer. In the current study, a two-step melt blending and post-annealing process has been adopted to mitigate the homocrystallisation and to produce full SC-PLA between enantiomeric poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA). In order to investigate the impact of melt flow-induced precursor structures on PLA matrix nucleation, a range of processing temperatures at the SC-PLA melting threshold were selected. Differential Scanning Calorimetry (DSC) investigations of pellets with 1, 3 and 5 wt.% SC-PLA revealed that the homopolymers were partially detached from the SC-PLA crystals. An increase in the weight percentage of SC-PLA resulted in the observation of self-nucleated crystallisation, accompanied by a notable rise in the number of nuclei, as seen under the Polarised Light Microscope (POM). Subsequently, the thin films obtained were then analysed using Atomic Force Microscopy (AFM), where the formation of shish-kebab structures was observed in SC-PLA nucleated samples.
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