In Situ Incorporation of Liquid Polysulfide Oligomer Modified MoS2 into Polysulfide Rubber (PSR) as Solid Crosslinker with Greatly Improved Dispersion Ability and Interfacial Interaction

Polysulfide rubber (PSR) is a versatile sealing material, but suffers from poor mechanical properties, which can be solved by increasing the crosslinking density and introducing fillers. In this study, functionalized molybdenum disulfide (MMoS₂) by in situ incorporation with different thiol-containing compounds is obtained. On the basis of the optimum content of 0.5 wt.%, the performance of MMoS₂/PSR is systematically studied. The results show that the interfacial interaction between MMoS₂ and the matrix is improved. In particular, PSR reinforced by MoS₂ modified with polysulfide oligomer (MoS₂-LPO) behaves the most excellently. Its solvent resistance and crosslink density are also improved by 14.2% and 39.4%, respectively. The storage modulus of MoS₂-LPO/PSR is 394% higher than that of the unmodified one. This is attributed to the MoS₂-LPO playing the role of filler and large-sized solid crosslinker at the same time. Through broadband dielectric spectroscopy (BDS), it is determined that MoS₂-LPO/PSR has the longest relaxation time due to the stronger interfacial interaction. In order to understand the effect of interfacial interaction between MoS₂ and PSR on the properties of the composites more clearly, MoS₂ modified with other functional groups are also discussed.