Porous structure development in PVC/modified bentonite composites: Influence of clay dispersion on porosity and sorption behavior

Polyvinyl chloride (PVC)-based composite membranes containing calcined bentonite (UCB) and organo-modified bentonite (AMB) were prepared by non-solvent-induced phase separation (NIPS) and evaluated for their porous structure and oil sorption performance. The results showed that clay modification significantly influenced membrane morphology and porosity. Increasing UCB content reduced membrane porosity from 71.2% to 61.2%, whereas AMB incorporation increased porosity up to 74.1%, indicating the formation of a more open and interconnected porous structure. These structural differences were reflected in the sorption behavior of the membranes. AMB-containing membranes exhibited the highest oil uptake, reaching 4.56 g g −1 for crude oil and 2.22 g g −1 for hydraulic oil, while maintaining low water uptake (0.19 g g −1 ). Mechanical and thermal characterization demonstrated that incorporating modified bentonite affected the overall performance of the PVC matrix, with composition-dependent changes in strength and thermal stability. Complementary density functional theory (DFT) calculations using simplified molecular models revealed differences in HOMO–LUMO energy gaps between PVC/UCB and PVC/AMB systems, providing qualitative support for the distinct interaction environments generated by clay modification. Overall, the results indicate that the dispersion state and surface modification of bentonite play an important role in controlling pore development and sorption behavior in PVC-based porous membranes, highlighting their potential for oil-related environmental applications.