This study presents a quantitative framework connecting dispersed phase morphology, interfacial characteristics, and impact toughness using polyamide 6 (PA6)/polyolefin elastomer (POE) blends as a model system. By combining kinetic monitoring with equilibrium analysis, the reactive blending process is shown to follow a saturation trend in which dispersed phase diameter dv decreases while interfacial thickness δ increases, following a modified power-law model (δ = a × dv–b + c). The toughening behavior is governed by the percentage of interfacial saturation, defined as the interfacial copolymer areal density (Σd) relative to its saturation limit (Σmax), which delineates three distinct regimes. At low coverage (80% Σmax), a “dense interfacial brush” suppresses debonding and activates matrix crazing, yielding supertoughness (>70 kJ/m2). These findings highlight that achieving supertoughness in plastic/elastomer blends requires reaching a critical interfacial saturation that stabilizes the phase boundary and enables efficient stress transfer across the interface.
Li et al. (Fri,) studied this question.