Designing Eco-Efficient Packaging Materials: Influence of Cloisite ® Characteristics on the Morphological Features, Physicochemical Performance, and Biodegradability of Organomodified Montmorillonite-PCL Nanocomposites

Poly(ε-caprolactone)-based nanocomposites containing Cloisite®30B (C30B, polar) and Cloisite®15A (C15A, non-polar) were synthesized via THF-assisted solution blending to investigate polarity-dependent dispersion, functional properties, and biodegradation at 3 and 5 wt% loadings. Structural characterization revealed organoclay-dependent morphologies: 3 wt % C15A promoted partial exfoliation within an intercalated structure, whereas 5 wt % C15A and C30B systems exhibited predominantly intercalated structures with increased aggregation. Rheological assessments revealed pronounced pseudo-solid behavior and elevated storage moduli, particularly in C15A composites, reflecting superior nanofiller dispersion. The incorporation of 5 wt% C15A and C30B into PCL enhanced crystallization, elevating crystallinity from 36.2% (neat PCL) to 39% and 45.9%, respectively. Nanoclay loading (C15A, C30B) significantly reduced water vapor permeability to 0.13 and 0.15 g/m·24 h·atm, respectively, due to filler-induced tortuosity. Nanoindentation measurements revealed that C15A exhibited superior mechanical properties compared to C30B, with increased modulus (765 MPa) and hardness (57 MPa), suggesting improved matrix–filler compatibility. Biodegradation assays using Aspergillus Niger confirmed accelerated fungal colonization on OMt-PCL surfaces (index 4), compared to neat PCL (index 1), attributed to the catalytic influence of well-dispersed silicate phases. These observations validate the applicability of OMt-PCL nanocomposites in the design of advanced eco-efficient materials, particularly targeting sustainable packaging technologies.