Morphology study on elastomers reinforced by zinc dimethacrylate II. in vulcanizates

The morphologies of various ZDMA-reinforced elastomers (including BR, SBR. EPDM, NBR, EPM, POE and HNBR) were studied by using SEM and TEM. It is shown that there are two essential dispersion structures in the vulcanizates of these systems: nano-scale dispersion structure and micron one. It is thought that nano-scale with strong reinforcing ability is formed by in-situ polymerization during peroxide curing process; while micron one without reinforcement for vulcanizates is the residual ZDMA particle. It is also found that the relative content and size of this two dispersion structures varies from different compound systems. For BR and SBR vulcanizates, there are more micron structures and the dimension of nano structure one is relatively smaller than those of other system. For EPDM, NBR, EPR, POE and HNBR vulcanizates, there is fewer microns structure and the dimension of nanometer one is larger slightly. The effect of size of original ZDMA particles on morphology of vulcanizae was also investigated. In POE system, ZDMA original particles with larger size lead to more micron dispersion structures. in vulcanizate. However, there is no considerable influence of size of ZDMA particles on morphologies of EPDM, EPM, NBR and HNBR systems. The details for the formation of these structures are illustrated. These differences in morphologies directly impact on the mechanical properties of vulcanizates.