In a recent study focused on the development of more sustainable materials for the rubber industry, researchers explored the potential of biochar synthesized from corn starch as an alternative to carbon black N772, a material traditionally used but associated with environmental and health concerns. This investigation, set against the backdrop of a growing emphasis on circular economy practices within industrial sectors, specifically analyzed biochar produced from corn starch with varying amylose/amylopectin ratios. The aim was to evaluate its reinforcing capabilities within styrene-butadiene rubber (SBR) composites compared to those reinforced with carbon black.

Biochar was generated through slow pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More and subjected to three distinct physical activation processes: CO2 activation, steam and nitrogen activation, and steam activation through pyrolysis of a biochar-water slurry. These processes were designed to alter the biochar’s physicochemical properties significantly, focusing on porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More, carbon content, oxygen content, and ashAsh is the non-combustible inorganic residue that remains after organic matter, like wood or biomass, is completely burned. It consists mainly of minerals and is different from biochar, which is produced through incomplete combustion.   Ash Ash is the residue that remains after the complete More concentration. Subsequently, the modified biochars were incorporated into SBR to assess their impact on the rubber’s curing characteristics and tensile properties.

Findings revealed that the type of starch used for biochar production (reflected in the amylose and amylopectin content) had a negligible effect on the composite’s reinforcing performance. However, biochars derived from high amylose corn starch demonstrated a propensity for longer scorch periods during the curing process. Among the activation treatments, biochar activated under steam and nitrogen conditions showcased the most favorable balance of tensile strength and flexibility. In contrast, biochar activated through the steam slurry method exhibited excessive brittleness, undermining its reinforcement potential despite a higher carbon content.

This study underscores the complex relationship between biochar’s physicochemical properties and its performance as a rubber composite filler. It suggests that while increasing biochar’s carbon content is achievable through physical activation, this does not inherently enhance its mechanical performance within SBR. Consequently, this research prompts further exploration of optimization techniques to refine biochar’s suitability as a sustainable alternative in the rubber filler industry, contributing to the sector’s shift towards greener materials.