Fumed silica, a nanomaterial with a high specific surface area, excellent chemical stability, and electrical insulation, serves as an effective filler for rubber compounding. Compared to traditional carbon black, silica (SiO₂), the main component of fumed silica, improves the hardness and tear resistance of tread rubber, making it a viable substitute in some formulations. However, silica-filled compounds generally exhibit lower tensile properties and abrasion resistance than carbon black. Fumed silica, with its higher structural integrity, provides additional reinforcement points within natural rubber matrices, enhancing tensile strength and abrasion resistance. Studies demonstrate that replacing carbon black with an equivalent amount of fumed silica as the primary filler significantly improves tread rubber’s hardness (by 20%) and 300% tensile modulus (by 14%) while also reducing rolling resistance and enhancing wet skid performance. Fumed silica’s large specific surface area and low density (10–15% of conventional silica) make it challenging to use directly as a tread rubber filler due to dust formation and prolonged mixing times. This study developed a process combining fumed silica with deionized water, followed by drying and ball milling. This treatment reduces the material’s volume, forming a cohesive gel that, upon processing, minimizes dust and significantly decreases mixing time and difficulty. The interaction between the hydroxyl (–OH) groups on the surface of fumed silica and water molecules likely results in hydrated silica. This interaction enhances surface polarity and forms a hydration layer, improving the hydrophilicity and dispersion of fumed silica in rubber matrices. This reduces the shear modulus difference (ΔG′) between low and high strain, maintaining a consistent elastic modulus over a wide strain range. Such stability enables rubber to perform better under dynamic loads or in complex working conditions. The experimental results demonstrate that the hydration–ball milling process enhances the tensile strength of vulcanizates, improves the dispersion of fumed silica in rubber, strengthens the filler network, boosts dynamic performance, and enhances the wet skid resistance of tread rubber.

Pyrolytic carbon black (CBp) is the main by-product of waste tire pyrolysis. CBp has high ash content and poor surface activity which leads to the composites reinforced with CBp has lower performance than composites reinforced with commercial carbon black, making it difficult to meet the requirements of tire. In order to realize the application of CBp in tires, the effect of surfactants on the properties of rubber composites prepared by wet mixing of CBp/natural latex was investigated. In the experimental process, sodium stearate (C₁₇H₃₅COONa), sodium dodecylbenzene sulfonate (C₁₈H₂₉NaO₃S), and sodium p-styrenesulfonate (C₈H₇NaO₃S) were used to improve the surface activity and uniform dispersion of the CBp in the natural rubber matrix. The experimental results showed that the dispersity of C₁₈H₂₉NaO₃S and C₈H₇NaO₃S modified CBp in rubber matrix has [X] and [Y] values of 7.5 and 7.9, and 9.3 and 9.5, respectively, and the dispersion of these rubber composites is significantly better than that of C₁₇H₃₅COONa. The rubber composites prepared by C₁₈H₂₉NaO₃S and C₈H₇NaO₃S surfactants has the better physical and mechanical properties. The rubber composite prepared by C₁₈H₂₉NaO₃S has the highest tensile strength of 25.63 MPa, which increment in tensile strength is 15.6% compare to the rubber composite prepared by C₁₇H₃₅COONa. Meanwhile the dynamic mechanical properties of rubber composites prepared by modifying CBp with C₁₈H₂₉NaO₃S and C₈H₇NaO₃S are better than CBp with C₁₇H₃₅COONa. The C₈H₇NaO₃S modified CBp/rubber composite has the lowest loss factor (tanδ) value at 60°C, and the C₁₈H₂₉NaO₃S modified CBp/rubber composite has the highest tanδ value at 0°C.

Spent Fluid Catalytic Cracking (FCC) Catalyst is a major waste in the field of the petroleum processing field, with a large output and serious pollution. The treatment cost of these waste catalysts is high, and how to achieve their efficient reuse has become a key topic of research at home and abroad. To this end, this paper conducted a mechanistic and experimental study on the replacement of some carbon blacks by spent FCC catalysts for the preparation of rubber products and explored the synergistic reinforcing effect of spent catalysts and carbon blacks, in order to extend the reuse methods of spent catalysts and reduce the pollution caused by them to the environment. The experimental results demonstrated that the filler dispersion and distribution in the compound are more uniform after replacing the carbon black with modified spent FCC catalysts. The crosslinking density of rubber increases, the Payne effect is decreased, and the dynamic mechanical properties and aging resistance are improved. When the number of replacement parts reached 15, the comprehensive performance of the rubber composites remained the same as that of the control group. In this paper, the spent FCC catalysts modified by the physical method instead of the carbon-black-filled SBR can not only improve the performance of rubber products, but also can provide basic technical and theoretical support to realize the recycling of spent FCC catalysts and reduce the environmental pressure. The feasibility of preparing rubber composites by spent catalysts is also verified.

This paper studies the material movement characteristics of waste tires in the catalytic pyrolysis reaction process. The reactor is divided into three zones by the correlation between the conversion rate α and the change of physical properties. The discrete element simulation software EDEM is used to simulate the movement characteristics of materials at different rotate speeds, pyrolysis reactor zones, and material states. The simulation results show that the different physical properties of reaction system are the main reason for the difference in the movement characteristics of the materials at the same speed, and the mixing effect of the materials in each zone are improved as the rotate speed of the pyrolysis reactor increases. At the same time, the viscous flow is the main state of waste tires in the pyrolysis process, and the mixing effect is extremely poor. To this end, the relevant research on the movement of the viscous solid material at low rotate speed is done, and it is confirmed that the addition of a high heat capacity medium has a significant effect on improving the movement of the viscous solid material.