Influence of Carboxylic Acids on Poly(lactic acid)/Thermoplastic Starch Biodegradable Sheets Produced by Calendering-Extrusion

摘要

Sheets of poly(lactic acid) (PLA) and thermoplastic starch (TPS) with citric and adipic acid additives were produced through a calendering-extrusion process at pilot scale, and its mechanical, barrier, thermal, and morphological characteristics were determined. According to the micrographs, citric acid improved the fragmentation and dispersion of starch granules by facilitating interactions with PLA chains and increasing interfacial adhesion. Citric acid also induced a significant increase in the tensile strength and elongation at break, reducing water vapor permeability, increasing crystallinity, but decreased slightly the thermal stability. Adipic acid did not demonstrate the same efficiency, even when mixed with citric acid.