Chong Sun

The anti-fatigue failure mechanism is proposed for plasma treated pyrolytic carbon black (MCBp) / silica filled natural rubber (NR), based on the evolution of micro-meso structures during tensile fatigue. The results demonstrate that plasma treatment induces pronounced etching and polarization effects on pyrolytic carbon black (CBp) derived from waste tires. MCBp significantly improves the silica dispersity in NR/MCBp/Silica. The particle network strength formed between MCBp and Silica aggregates is higher than that between CBp and Silica aggregates. Consequently, the fatigue life of the NR/MCS-40 increases by approximately 20% compared with that of the NR/CS-40, even superior to that of the NR/Silica-50. Surface fatigue cracks of the samples predominantly propagate in the different directions between hybrid fillers and silica filled systems. The fatigue fracture surface of the NR/CS-40 and NR/Silica-50 systems exhibits a lamellar fracture morphology, while the NR/MCS-40 system shows a grooved fracture structure. The filler dispersity and cross-linking density interact with each other during the fatigue process. Good filler dispersity and an appropriate particle network strength are key factors for enhancing the fatigue resistance of filled rubber systems. This work provides a new insight into enhancing the fatigue resistance of filled rubber systems and the utilization value of CBp.

Ire wear resistance is an essential performance metric for advancing the sustainable development of automotive industry. However, conventional enhancement strategies, such as the use of silane coupling agents, often entail the release of volatile organic compounds (VOCs), while traditional fillers contribute to environmental pollution, thus limiting their eco-friendly application. To address these challenges, we propose a surface activation-induced polarity regulation strategy for recycling waste-tire pyrolytic carbon black to obtain pyrolytic carbon black (P-CBp), serving simultaneously as a dispersant for silica and a reinforcing filler in rubber composites. The modified CBp exhibits enhanced surface activity and stronger interfacial interactions with silica, leading to significantly improved dispersion within the rubber matrix. Compared to composites prepared with silane coupling agents, this strategy achieves a 105% increase in tensile strength, along with a 16.5% reduction in the friction coefficient and a 54.0% decrease in wear volume. Moreover, the worn surface roughness shows minimal variation, with only a 0.75% change. These results establish functionalized CBp as a dual-role hybrid filler and dispersant for silica in the rubber systems, offering a promising strategy for the value-added application of modified pyrolytic carbon black in sustainable tire manufacturing.

Short carbon fiber (SCF) reinforced polyetheretherketone (PEEK) composites incorporating graphite and submicron‐sized ZnS/TiO ₂ particles were fabricated to investigate the influence of carbon fiber surface sizing on tribological performance. Dry sliding tests were performed using a block‐on‐ring configuration over a wide range of normal pressures and sliding speeds. The results indicate that the tribological behavior of the PEEK composites is more sensitive to sliding speed than to normal pressure. Compared with neat PEEK, the introduction of SCFs combined with graphite and ZnS/TiO ₂ particles significantly reduces both the friction coefficient and wear rate. Notably, PEEK‐C reinforced with higher sizing content carbon fibers exhibited a 67% reduction in the friction coefficient and a 65% decrease in specific wear rate compared to PEEK‐B at 1 MPa and 4 m/s. Even under high loading of 4 MPa at 2 m/s, PEEK‐C maintained a 51% lower specific wear rate than PEEK‐B, demonstrating superior stability across a broad pv‐range. Microstructural analysis reveals that the enhanced wear resistance is mainly attributed to improved fiber‐matrix interfacial bonding and more efficient load transfer. In addition, optimized surface sizing promotes the formation of a continuous transfer film on the steel counterface, acting synergistically with ZnS/TiO ₂ particles to mitigate wear. These findings underline the critical importance of surface sizing in tailoring the tribological performance of SCF‐reinforced PEEK composites for demanding engineering applications.

The erosion and polarization effects were much more evident with the increase in plasma power for pyrolysis carbon black (CBp) arising from waste tire. However, a strong fusion effect appeared when the plasma power reached 600 W. CBp‐400 W had the best dispersion in the rubber matrix and the deepest strong interaction with molecular chains. However, CBp‐600 W had the worst dispersion and the most remarkable weak interaction with the rubber matrix. Compared with NR/CBp‐0 W, the tensile strength increased by 16.6%, and the DIN abrasion volume decreased by 8.1% for the NR/CBp‐400 W. Its coefficient of friction (COF) and abrasion resistance enhanced by 22.6%/56.5% (7 N: 0.25 m/s), 13.5%/30.1% (7 N: 0.5 m/s), 7.6%/28.8% (14 N: 0.25 m/s), and 20.3%/34.1% (14 N: 0.5 m/s) under dry friction conditions. The steady COF of NR/CBp‐400 W increased by 53% compared with NR/CBp‐0 W under wet friction conditions, and the regulation of the COF was in accordance with that of the tanδ at 0°C detected by dynamic mechanical measurement. In this work, it was proved that 400 W was the optimized plasma power. Filler dispersion and strong filler–polymer interaction were crucial factors in enhancing abrasion resistance. Additionally, this research introduced a novel approach for assessing the wet‐slip resistance of rubber materials.

With the growing volume of waste rubber products, the pressures on the environment and resources become increasingly serious. The reclamation of waste rubber products is one of the practical methods to meet this challenge. Therefore, the application of reclaimed rubber (RR) attracts researchers’ attention. In this work, different contents of natural rubber (NR) matrix are replaced by RR and the reinforcing behavior of the RR phase is discussed. The results show that the crosslinking density, Payne effect and 100% modulus increase with increase in RR content in the NR/RR blends when the RR content is not more than 60 phr, and then drop when the RR content gets to 80 phr. It is inferred that both the NR and the RR constitute co‐continuous phases when the RR content is 60 phr, and the RR phase is the only continuous phase when its content reaches 80 phr, which can be confirmed by SEM observation. Besides, the curing rate is enhanced with increase of the RR content. It is also found that structures with high crosslinking density appear when the RR is incorporated into the NR matrix. Finally, it is proposed that carbon black in the RR, a structure with high crosslinking density and a continuous rubber matrix are important factors influencing the reinforcement behaviour in RR filled rubber composites. © 2023 Society of Chemical Industry.