Synergistic effects of kaolin and talc in a bromobutyl rubber compound for syringe plunger application

Abstract

The effectiveness of separate and combined incorporation of two natural, inexpensive, and nontoxic filler materials, kaolin and talc, at their various proportions in a bromobutyl rubber (BIIR) compound for a medical syringe plunger was investigated. The dispersion of kaolin was finer and more homogeneous than talc in BIIR. The curing was also enhanced in the presence of kaolin than talc. The difference in dispersion as well as reinforcing effects of the different fillers were reflected in the dynamic mechanical properties of the compounds. Tensile properties of the compounds were not significantly varied with varying kaolin/talc ratio of the compounds, however, tear strength decreased for higher contents of talc in the compounds. A significant synergistic reduction of compression set was achieved for 75/15 ratio of kaolin and talc in the rubber compound, very important for a plunger compound.