Reactive extrusion (REX) has been shown to be an extremely valuable industrially relevant technique for the producing advanced bio-based materials. Different classes of reactions have taken advantage of the high shear present inside of a twin-screw extruder; including ROP polymerizations of poly(ε-caprolactone) and polylactide (PLA) and starch modification reactions. This presentation describes reactive extrusion for the compatibilization of PLA based blends and enzymatic catalyzed ring opening polymerizations. PLA was blended with a ductile component, poly(ω-hydroxytetradecanoic acid) (PC14) results in a compatibilized PLA/PC14 blend. Numerous processing parameters were investigated and optimized processing conditions included a reaction time of 15 minutes, screw speed of 150 RPM, reaction temperature of 200°C conducted with the addition of 200 ppm Ti(OBu)4 gave PLA blends with high strain at break values, with little losses to the overall blend’s tensile modulus. The addition of 200 ppm Ti(OBu)4 was found to produce PC14-block-PLA, as evidenced by NMR, and thus increasing the interfacial adhesion between PLA and PC14. The addition of 5wt% PC14 increased PLAs strain at break from 3% to 150%, with a small decrease in tensile modulus. REX was also used for the bulk ring opening polymerization of ω-pentadecalactone (PDL) to poly(ω-pentadecalactone) (PPDL). REX conducted at 90°C in the presence of 10% immobilized Candida antartica Lipase B with a screw speed of 60 RPM for 15 minutes resulted in PDDL chains with Mn 163,000 g/mol and complete monomer conversion. To explore the possibility of continuous enzymatic REX, processing conditions such as CALB concentration, reaction temperature and reactive time were investigated and correlated with SEC and NMR results. Enzymatic reactive extrusion is expected to result in the synthesis of new environmentally friendly polymers at greatly reduced cost.

From compatibilizing polymer blends to enzymatic polymerizations using reactive extrusion

251st National Meeting (2016)

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