Effect of residence time in the reactor on the reinforcement of biochar in rubber compounds

In the present work, the effect of residence time on the production of biochar by the pyrolysis process of Pinus spp. was investigated. Biochar was produced at three different residence times in the reactor (30, 60, and 240 min). The effect of residence time on the load in the pyrolysis process was evaluated based on the rheometric, physical and mechanical properties of the elastomeric compounds. The shortest residence time, 30 min, produced a biochar with a graphitic structure (turbostratic) that was ideal for the interaction between load and elastomer and caused the least possible disturbance to the crystallization process by stretching the natural rubber, which was observed from the tensile strength, while maintaining the mechanical properties. As the residence time increased, it was observed that the more crystalline structure interfered with the crystallization process of the natural rubber when stretched, causing a decrease in tensile strength and decreasing the interaction between the load- elastomer, thus increasing the vulcanization time of the rubber. The compound was prepared using the filler with the longest residence time (NR/BIO240min).