Enhanced Performance of Bio‐Based Epoxidized Natural Rubber/Natural Rubber/Silica Nanocomposites via Manipulation of Phase Interface by Two‐Stage Mixing Process

Epoxidized natural rubber (ENR), derived from natural rubber, has emerged as a viable bio‐based alternative to petroleum‐derived solution‐polymerized styrene‐butadiene rubber (SSBR) in green tire applications, owing to its enhanced mechanical properties and wet skid resistance. However, in traditional mixing processes, the distinct polarity and reactivity differences between silica, ENR, and natural rubber (NR) inevitably lead to the preferential migration and severe agglomeration of silica in the ENR matrix, resulting in a heterogeneous network and compromised mechanical performance. To address this, a novel two‐stage mixing strategy based on silica pre‐dispersion was employed in this work. An NR/silica masterbatch was initially prepared to ensure silica dispersion, followed by a second mixing stage with ENR to fabricate a series of nanocomposites. The phase morphology and silica dispersion mechanism were investigated using transmission electron microscopy (TEM) and atomic force microscopy‐nano‐Fourier transform infrared (AFM‐Nano‐FTIR). The results revealed that this strategy facilitates strong affinity and reactivity between silica, NR and ENR, establishing a “double‐coupling” network structure. Consequently, compared to traditional one‐stage mixing process, the composites prepared via the two‐stage mixing process exhibited significantly improved filler dispersion, enhanced wet skid resistance, and superior mechanical properties.