Potential of a Pyrolytic Coconut Shell as a Sustainable Biofiller for Styrene–Butadiene Rubber

This paper presents research undertaken on pyrolytic coconut shell char to evaluate its potential as a sustainable and renewable substitute filler for carbon black in rubber. Carbon black is the most widely used filler in rubber. Its manufacture from nonrenewable feedstock is unsustainable and energy-consuming and contributes significantly to global CO2 emissions. The pyrolytic properties of coconut shell were evaluated; response surface methodology was applied to model the relationship between the pyrolysis conditions and char properties. Coconut shells were pyrolyzed using a laboratory-scale furnace under various temperatures (400–800 °C), residence times (0–2 h), and atmospheric flow rates. Comparisons were made between the char and commercial carbon blacks for their physical and chemical properties (surface area and pH). Comparable char pH and surface area properties were achieved (optimal char exhibited 300 m2/g surface area). Selected samples were tested in-rubber, with the performance of the filled styrene–butadiene rubber showing 2 MPa at M100%.