In-situ interfacial engineering towards highly fatigue resistant rubber composites enabled by aniline-functionalized oligomers

Engineering aniline handles into rubber skeleton constitutes as the most straightforward, yet unexplored pathway for preparing aniline-functionalized interfacial regulators towards rubber/CB composites. Herein, we propose a facile pyrolysis strategy to prepare aniline-functionalized elastomeric oligomers, which leverages the dynamic covalent polymerization between the abundant reactive di/polysulfide segments of vulcanizates and m -phenylenediamine (MPD). Upon regulating MPD dosage, MPD moieties are rationally inserted into the di/polysulfide segments and synchronously disintegrate the sulfur-based network architecture, thereby achieving MPD-functionalized oligomers (MFO) with adjustable MPD content. The obtained oligomers feature with multiple aniline handles and rubber-based segments, which can enable strong interfacial linkages between CB and rubber matrix in the composites. Even incorporating a small amount of the obtained oligomers (i.e. 0.21 wt% of MPD moieties), the thickness of the interfacial region and the CB dispersion can be considerably enhanced, leading to reductions of ∼21.3 % and ∼22.5 % in temperature rise and rolling resistance of the composites, respectively. Moreover, this also synergistically promotes tip deflection/branching and energy dissipation during crack propagation. Meanwhile, the reduction in temperature rise of composites further maintains the network robustness under cyclic loading. Therefore, the crack growth rate of the composites shows a remarkable decrease (∼64 %) at high tear energy, along with a substantial increase of ∼75 % in ultimate fatigue life. We envision the present methodology, which adopts functionalized oligomers as novel interfacial regulators for rubber composites, has great potential in exploiting high-performance engineering rubbers in terms of energy conservation and superior fatigue resistance.