Polymers make up an important component of the manufacturing industry. Their density and mechanical properties makes them desirable for many applications. Currently much polymer produced is from non-renewable sources which adds to waste after disposal. PLA is a bio-based polymer shown to be promising in many studies but its inherent brittleness prevents wide scale application of the polymer. One readily feasible alternative is to reinforce PLA with fillers as a means to improve mechanical properties. Two types of PLA based bio-composites were considered: PLA-Lignin & PLA-Tannin composites. PLA was the matrix in these composites with the fillers either being Lignin or Tannin. Composites containing 5, 10, and 15 wt % of the fillers were studied. The composites were fabricated by means of melt blending in a twin screw compounder followed by injection molding. SEM morphological, mechanical, and dynamic mechanical evaluations of the composites were performed. Tan delta values of both Lignin and Tannin based PLA composites increased with increasing addition of fillers with the exception of PLA with 5 wt% Tannin. Lignin appears to have a plasticizing effect on the initial tensile stiffness while tannin appears to have a stiffening effect on the initial tensile stiffness. Glass transition temperatures of all composites do not seem to change significantly from that of pure PLA.

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