Interface Coupling in Rubber/Carbon Black Composites toward Superior Energy-Saving Capability Enabled by Amino-Functionalized Polysulfide

Natural rubber/carbon black (NR/CB) composites have found indispensable application in aircraft tires. Interfacial modification of NR/CB composites for acquiring uniform CB dispersion and strong interfacial adhesion is a persistent and challenging theme, as it is a prerequisite to improve comprehensive mechanical properties and decrease energy loss of the composites under dynamic deformations. In this work, we reported the use of an amino-functionalized polysulfide (PDAS) synthesized by inverse vulcanization of sulfur and m-phenylenediamine as a novel interfacial modifier in NR/CB composites. Specifically, the amino of PDAS can react with the carboxyl groups on the CB surface, meanwhile the polysulfide chains of PDAS can react with rubber chains, enabling the crosslinking of NR and establishment of a molecular bridge between NR and CB. The influences of PDAS dosages on CB dispersion and interfacial adhesion are revealed, and their correlations with composite properties are discussed. Compared with the unmodified counterpart, CB dispersion is greatly improved and interfacial adhesion is significantly enhanced in the PDAS-modified composite having an identical crosslink density, leading to remarkably decreased hysteresis loss. In addition, PDAS can significantly resist thermal-oxidative aging of the composites due to its radical scavenging activity.