Advantages of using a dual‐filler system with carbon black and rockwool fiber on Nitrile Rubber composites from a technical standpoint

Abstract

AbstractThis study produced and characterized composites based on nitrile rubber reinforced with rockwool fiber (RW) and carbon black (CB). Ten formulations with dual‐filler loading amounts ranging from 0 to 40 phr of CB and RW were designed using a simplex‐centroid mixture. The composites were assessed regarding their rheometric, rheological, mechanical, and thermal properties. The use of the RW in the dual‐filler system contributed to overall improvements in Shore A hardness, tear strength, modulus at 50%, and resilience, as well as reducing the Payne effect. Instead of using 40 phr of CB alone, a dual‐filler system comprising 20 phr of CB and 20 phr of RW lowers the Payne effect by around 60%, improves resilience by 35%, modulus at 50% strain by 8%, and the residual stress at equilibrium (σ∞/σ0) by 7%. On the other hand, the tensile strength is reduced by 23%. The optimum cure time, crosslink density, and maximum decomposition rate temperature were not affected by the rockwool's presence in the dual‐filler system. In general, the use of RW in combination with CB is advantageous mainly because it reduces compressive stress relaxation, which is an important property for sealing applications.Highlights Dual‐filler systems based on carbon black (CB) and rockwool fiber (RW) offer advantages. RW‐rich dual‐filler systems reduce stress relaxation. RW‐rich dual‐filler systems reduce the Payne effect. CB‐rich dual‐filler systems increase tensile strength.