Development of expanded graphite filled natural rubber vulcanizates in presence and absence of carbon black: Mechanical, thermal and morphological properties

As nanosized expanded graphite (EG) reveals a similar layered structure like organoclay and also it has a high expansion ratio so rubber chains can easily be intercalated into the gallery space. To improve the dispersion of EG in the rubber matrices, primarily the surface modification of the expanded graphite have been done and then the modified expanded graphite (MEG)/polar compatibilizer [epoxidized natural rubber (ENR)] master batch have been prepared by solution mixing method in the laboratory. After that the MEG/ENR master batch have been mixed with bulk natural rubber (NR) in presence and absence of carbon black (CB) in a laboratory scale open two roll mixing mill. Wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analysis of the nanocomposites revealed that MEG was intercalated and as well as delaminated in the NR matrix. Scanning electron microscope (SEM) images of the nanocomposites showed very rough surface than the pure NR matrix. In presence of expanded graphite the crack paths are channelized and coincide in one point suggesting the effect of plate like expanded graphite to acts as a barrier. We have got improved mechanical, thermal and dynamic mechanical properties for the MEG and MEG/CB loaded NR compounds compared to EG and EG/CB loaded NR compounds.

► Fabricate natural rubber based nanocomposites containing expanded graphite (EG). ► Study the effect of EG and modified EG on the properties of natural rubber. ► Comparison of the results of EG/MEG filled and (EG/CB)/(MEG/CB) filled NR vulcanizates. ► EG can reduce the dose of CB in tire application. ► MEG loaded NR vulcanizates in presence and absence of CB show superior properties.