Summary: Pyrolytic carbon black (CBp) has been prepared by rubber crumb pyrolysis under nitrogen flow at 700 °C. The CBp obtained by this process had an average surface area of 81 m2 · g?1 and was obtained in 43% yield over the starting rubber crumb. Although the CBp surface area can be increased up to 109 m2 · g?1 by washing away the Zn‐ and Si‐based ashes with HF treatment, the CBp was tested in a standard NR/SBR‐based formulation without any purification and ash extraction. CBp was tested at increasing loading levels as partial or full replacement of a standard N339 furnace carbon black. CBp depresses the physical properties of the rubber compound in a way which is directly proportional to the amount added. The reason of this result and the limited reinforcing effect is discussed in terms of low surface area and low structure in comparison to N339 carbon black as well as in terms of low surface activity, the interference of the ashes and the poor dispersion. Ideas of further development works are outlined.
The adhesion property between rubber compounds containing different types of adhesion promoters (resinous adhesion promoter (containing both methylene donor and methylene acceptor), cobalt salt and zinc borate) and different loading amounts of sulfur and brass-plated steel cords was investigated to understand the effect of sulfur loading in the rubber compounds on their adhesion characteristics to the brass-plated steel cords. The adhesion property of the rubber compounds to brass-plated steel cords was largely dependent on both the type of adhesion promoter and the loading amount of sulfur in the rubber compounds. The pull-out force of adhesion samples increased significantly with increasing loading amount of sulfur in the rubber compounds containing resinous adhesion promoter, whereas it decreased slightly with increasing loading amount of sulfur in rubber compounds containing cobalt salt or zinc borate. In humidity aging, the best adhesion retention was observed in the rubber compound containing zinc borate and low loading of sulfur. Regardless of the type of adhesion promoter, adhesion retention after thermal aging treatments improved with increasing loading amount of sulfur in the rubber compounds. The adhesion property was interpreted in terms of the interphases formed between the rubber compounds and the brass-plated steel cords as studied using Auger electron spectroscopy. 相似文献