Filler Migration Research Articles

The photo-oxidation of EPDM rubber: Part V—mechanical properties degradation of vulcanized filled samples

Changes in mechanical properties produced by the photochemical aging of peroxide-vulcanized EPDM rubber, containing alumina trihydrate as filler, are described. Different changes of the stress and elongation at break are observed for filled and unfilled samples upon irradiation. These are assigned to different degradation reactions caused by the filler. The results indicate that crosslinking predominates in the filled vulcanizate while in the non-filled vulcanizate crosslinking and chain scission occur simultaneously. The filled vulcanizates show a higher degradation rate. Filler migration to the surface of the aged vulcanizate was detected by scanning electron microscopy.

The investigation of structural and morphological changes after the chlorination of rubber surfaces

AbstractThe samples of vulcanized rubber compounds with natural rubber (NR) and styrene‐butadiene rubber (SBR) were prepared. The surface chlorination of samples was performed by immersion of strips in aqueous solution of sodium hypochlorite and in hydrochloric acid in dependence of time and in temperature range from 20 °C to 80°C. The changes of chemical structures, thermal stability and morphological properties of chlorinated vulcanizates were recorded by IR‐FMIR spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide angle X‐ray diffraction (WAXD) and scanning electron microscopy (SEM). Extremely heterogeneous complex mechanisms of chlorination and parallel degradation processes in dependence on time and temperature above all were indicated and compared to NR and SBR vulcanizates. At higher temperatures the structural changes in elastomeric matrix in connection with selective separation and surface migration of multicomponent filler due to agressive media were observed.

Barus effect in filled polymer melts

AbstractThe influence of fillers on the post‐extrusion swelling (Barus effect) of polymer melts is explored with the use of three model fillers in poly(styrene–acrylonitrile). The filler effect is shown to be more complex than simple dilution of the polymer. The role of such factors as melt rigidity, tendency toward plug flow, trapping of matrix in filler aggregates, and filler migration are considered.