Effect of dynamic vulcanization on co‐continuous morphology

Abstract

Effect of dynamic vulcanization on co-continuous morphology This study examines the effect of dynamic vulcanization on the co-continuous morphology in ethylene-propylene-diene terpolymer (EPDM)/polypropylene (PP) blends using a technique of morphology investigation involving focused ion beam (FIB) etching of the sample surface, followed by topological investigation of the sample surface using tapping mode atomic force microscopy (TMAFM). The FIB ion etching rates of EPDM and PP are distinctly different, and these differences create a significant topological contrast between the phases when subsequently analyzed by atomic force microscopy. This approach allows for the high-resolution observation of dispersed EPDM, and phases as small as 100 nm, are clearly identified. Since it is shown that the etching rates of noncrosslinked and crosslinked EPDM are similar, it was necessary to selectively remove the noncrosslinked EPDM phase by solvent dissolution. This combination of techniques then allows for the clear distinction of polypropylene, as well as noncrosslinked and crosslinked EPDM phases in the blend. The high-resolution micrographs together with the continuity data, surprisingly, indicate that a noncrosslinked co-continuous EPDM phase (␣-network) transits to a finer network of crosslinked EPDM (␤-network) after dynamic crosslinking. It is suggested that this

Relationship between structure and properties in high‐performance PA6/SEBS‐g‐MA/(PPO/PS) blends: The role of PPO and PS

“…The continuity of the dispersed phase was calculated according to eq. : where m 1 is the mass of initial sample, m 2 stands for the mass of the dried sample after sufficient immersion.…”

Synergistic effect of SBS and trimethylopropane trimethacrylate (TMPTMA) on dynamically vulcanized SEBS/PP blends

“…To obtain SEBS/PP blend with good solvent resistance, appropriate hardness and processability, the key point was to form the structure with high‐volume‐fraction SEBS dispersed in low‐volume‐fraction PP matrix. The just mentioned morphology could be obtained by in situ crosslinking of SEBS in PP phase, and the obtained blends were called thermoplastic vulcanizates (TPVs) …”

Influence of network structure on the viscoelastic properties of dynamically vulcanized rubber/plastic blends: An alternative approach to understand the microstructure evolution

“…from P34 to P33 TPVs. The effect of these morphology formations should be reflected in the mechanical properties of the respective TPVs and according to the explanations given previously by several researchers, the TPVs having finely dispersed morphology should assert highest mechanical properties which M a n u s c r i p t 19 | P a g e should deteriorate with the increase in rubber agglomeration [4,21,25]. But, in actual, the results appear in opposite.…”

“…It has been reported that the cross-linking and breakup of the rubber phase is the primary factor responsible for the phase inversion of TPVs during dynamic vulcanization [17][18][19][20]. Several prior studies have been reported earlier describing the morphological evolution of the rubber phase in the TPVs during dynamic vulcanization [4,[21][22][23][24].…”