About the Seminar:

Polymer blends are a great pathway to create materials with enhanced material properties that are also tunable by varying the ratio of the blend. Blending offers an easier pathway compared to copolymerization, but miscibility of polymers in a blend is a common challenge.  Poly(L-lactic acid) (PLLA) and poly(3-hydroxybutyrate) (P3HB) are both biosourced polymers, that each offer a different set of material properties.  Both PLLA and P3HB are biodegradable and can be produced from biosourced starting materials, making them attractive sustainable options. It has previously been shown that control of tacticity can produce syndio-rich P3HB (sr)-P3HB and iso-rich P3HB (ir)-P3HB. These installed stereodefects help to enhance the mechanical properties of perfectly isotactic P3HB, which by itself is very brittle, to produce syndiorich and isorich P3HB which are much tougher. PLLA is known for its high tensile strength and rigidity but suffers from brittleness, whereas stereodiverse P3HB is tougher and more ductile, but does not have the tensile strength near the level of PLLA. To access these tunable properties by combining PLLA and P3HB the two polymers must be made more miscible because the mixing of different polymers is thermodynamically unfavorable. Here we will look at how transesterification can be used to improve the miscibility of polymer mixtures to then enhance the material properties of the blend.