Effects of Heat and Pressure on Microstructures of Isobutylene-Isoprene Rubber (IIR)/Clay Nanocomposites

Summary: In this work, the effects of heat and pressure on microstructures of isobutylene-isoprene rubber/clay nanocomposites prepared by solution intercalation (S‐IIRCNs) are investigated. Not only are the local intercalated structures monitored by wide‐angle X‐ray diffraction, but the spatial distributions of the silicate particles are also observed by transmission electron microscopy. The changing behavior of microstructures of S‐IIRCNs is strongly dependent on the temperature of the thermal treatment. The observed phenomena are completely different from those in IIRCNs prepared by melt blending (M‐IIRCNs), which were reported in a previous paper. Various experiments suggest that the presence of residual solvent molecules in S‐IIRCN plays a key role on the microstructural change of S‐IIRCNs caused by heat and pressure. The possible microstructural models for untreated and treated S‐IIRCNs are presented, which could well interpret all observed phenomena. Finally, guidelines are proposed for adjusting the curing conditions of the system to achieve the desired intercalated/exfoliated morphology, and a new method for preparing rubber/clay nanocomposites with good dispersion states by melt blending is put forward.TEM images of IIR/clay nanocomposites prepared by solution-intercalation before (left) and after thermal treatment at 160 °C and atmospheric pressure (right).