Poultry eggshell effects on microporous poly(lactic acid)-based film fabrication for active compound-releasing sachets

Poultry eggshells (ES) were used to create microporous structures as an alternative and sustainable filler in a poly(lactic acid)/polybutylene succinate (PLA/PBS) blend designed for sachet use. Crude chicken eggshell (CES) and duck eggshell (DES) are utilized as natural calcium carbonate (CaCO 3 ) sources by systematically varying filler content. Using CES and DES as sustainable fillers produces smaller pore diameters (ranging from 300 to 500 nm), a higher pore density (~ 10 6 pores/mm 2 ) and greater pore homogeneity within the PLA/PBS matrices. Poultry ES also improves calcium dispersion within the PLA/PBS matrices, compared to the highly variable pore sizes which cause the calcium agglomeration clearly observed in the PLA/PBS/CaCO 3 composites. Moreover, the organic residuals contained in the crude poultry ES promote interfacial adhesion in PLA/PBS matrices, resulting in uniform micropore distribution. The obtained morphologies of the PLA/PBS/poultry ES composites permit oxygen and water permeation comparable to those of conventional plastics currently used as active compound-releasing sachets. The stress–strain curves also reveal slightly improved toughness with 0.3 phr poultry ES. Lastly, poultry ES also induces crystalline PLA and PBS in α -forms with X c,PLA of 20–30% and X c,PBS of 30–50% and maintains high tensile strength, similar to that of PLA/PBS/CaCO 3 composites.