Search

During the blending process, the choice of lubricant used in the internal mixer significantly affects the properties of composite materials. This study thoroughly investigates the mechanisms that enhance the mechanical properties and anti-wear characteristics of Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials by employing both commonly used lubricants and graphene-based lubricant mediums. The research offers data-driven insights to enhance material performance during internal mixer blending and protect the end-face metals. The incorporation of graphene as a lubricant additive results in its deposition on friction pair surfaces, forming a protective anti-wear layer that prevents direct contact between the friction pairs and effectively reduces wear. Throughout the blending process, the composite materials inevitably come into contact with the lubricant. This research reveals that the addition of lubricant improves the dispersion of SiO 2 particles while reducing aggregate formation. Consequently, the SiO 2 particles-TESPT-rubber crosslinking network becomes denser, significantly enhancing the performance of Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials. Specifically, when using commonly used lubricant mediums, the material's hardness, tensile strength, and tear strength increase by 0.88 %, 7.8 %, and 4.5 %, respectively. In contrast, under the graphene lubricant medium, these properties improve by 2.7 %, 16.8 %, and 24.9 %, respectively. Notably, Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials using the graphene lubricant medium experience substantial reductions in rolling resistance and improved anti-wet skid performance. When comparing Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials with and without lubricants, composites prepared with both commonly used lubricants and graphene lubricants show significant reductions in metal wear and changes in metal surface roughness. Metal wear decreases by 17.5 % and 28.7 %, respectively, while changes in metal surface roughness are reduced by 46.3 % and 68.7 %, respectively. • Choice of lubricant affects composite properties in blending. • Lubricants enhance SiO 2 dispersion, densifying networks, boosting properties. • Lubricants notably reduce metal wear, graphene ones most effective. [ABSTRACT FROM AUTHOR]

During prolonged operation, the end face of the internal mixer, a crucial component in rubber processing, experiences wear, resulting in an increased gap between the mixing chamber and the end face. This gap can lead to material leakage and reduced mixing efficiency, negatively impacting rubber properties. To address this issue, researchers have introduced dynamic covalent bonds into the molecular rubber chains, giving the material self-healing properties. This advancement is essential for extending rubber lifespan and reducing production costs. One common approach involves adding methacrylic acid (MAA) and excess zinc oxide (ZnO) to create ionic crosslinking networks, limiting covalent crosslinking and enabling in-situ polymerization of MAA/ZnO, resulting in self-healing capabilities. However, the strong acidity and corrosive nature of MAA can cause metal wear. In our study, we mechanically blend MAA with ZnO to produce zinc methacrylate (ZDMA)/rubber composites. We investigate the in-situ synthesis mechanism of MAA and ZnO and assess the impact of MAA on the friction and wear of the internal mixer's end face. Our findings reveal that ZDMA ion pairs form an "ion cross-linked network" within the rubber chain, hindering SiO 2 particle dispersion and increasing aggregation within the rubber matrix. This compromises dispersion and leads to abrasive wear from SiO 2 particles, corrosive wear from high-temperature water vapor, and corrosive wear from MAA. Additionally, excessive ZDMA self-polymerization alters SiO 2 particle agglomerates. The strong acidity of MAA and the "ion cross-linked network" within the rubber matrix significantly affect SiO 2 particle dispersion, friction coefficients, metal surface roughness, and metal wear. Our comprehensive analysis, including SEM, dispersion, RPA, metal surface morphology, and CSM friction wear tests, identifies the optimal cross-linking effect with the addition of 15 phr of MAA, resulting in a well-defined "ion cross-linked network" within the rubber matrix, enhancing rubber performance. However, SiO 2 particle dispersion is compromised, leading to increased agglomeration and heightened metal wear. • Prolonged operation of internal mixers causes wear, increasing the gap, impacting rubber quality. • Self-healing rubber with dynamic covalent bonds extends lifespan and reduces costs. • A method involving MAA and ZnO for self-healing, but MAA's acidity causes metal wear. • Blending MAA and ZnO into ZDMA/rubber composites affects dispersion and wear. • An optimal MAA amount enhances rubber performance but compromises SiO 2 dispersion and increases metal wear. [ABSTRACT FROM AUTHOR]

Internal mixers play a critical role as blending equipment in the rubber industry, operating for extended hours under high intensity. Investigating the wear patterns of internal mixers holds paramount importance in curbing dust leakage and prolonging their operational lifespan during the mixing process. Thermal cracked carbon black (CBp), an economically viable material derived from waste rubber, stands as a potential substitute for other carbon blacks in specific applications. This substitution aids in waste rubber recycling, thereby promoting ecological sustainability. This study centers on the amalgamation of CBp and graphene oxide (GO) in varying proportions, incorporated into the rubber matrix via mechanical blending. The objective is to produce composite materials, namely CBp/GO/NR, and comprehend the synergistic mechanisms between CBp and GO. Furthermore, the study analyzes the impacts of different CBp/GO ratios on metal friction and wear at the internal mixer's end faces. Scanning electron microscopy (SEM) observations divulge a collaborative behavior between GO and CBp particles within the rubber matrix, culminating in a spatial "honeycomb" network structure. On one hand, GO's two-dimensional planar network structure aids in CBp particle dispersion. Conversely, this planar network restricts the overflow of aromatic oils in CBp particles, influencing oil film formation on the rubber surface. Simultaneously, the planar network of GO creates a physical isolation layer between the rubber and the metal components. The inclusion of GO in the rubber matrix introduces notable alterations in CBp particle dispersion, friction coefficient, metal surface roughness, and metal wear. In summary, the optimum interaction between GO and CBp particles is achieved when the GO content in the composite material reaches 4 phr. This interaction leads to superior CBp particle dispersion and minimal metal wear in the composite material. • Produce CBp/GO/NR composites, understand CBp and GO synergy. • Analyze CBp/GO ratios on metal friction/wear at mixer faces. • SEM shows collaborative GO and CBp behavior, "honeycomb" structure. • Optimal GO-CBp interaction at 4 phr in composite material. [ABSTRACT FROM AUTHOR]