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The continuous operation of essential refining equipment, internal mixers, leads to wear on their end faces, resulting in an increased gap between the mixer chamber and the end face. This, in turn, causes material leakage, reducing mixing efficiency and adversely impacting rubber performance. Therefore, investigating metal wear on the mixer's end face during the mixing process is essential. Scholars have introduced dynamic covalent bonds into rubber molecular chains, bestowing self-repairing capabilities upon the materials. This innovation has significant implications for extending rubber lifespan and lowering production costs. It involves adding methacrylic acid (MAA) and excess zinc oxide (ZnO) to construct an ionic crosslinking network, limiting covalent crosslinking of rubber molecules and enabling in-situ polymerization of MAA/ZnO, resulting in self-repairing properties. However, it is crucial to consider corrosive wear induced by MAA's strong acidity on metals. This study combines MAA, ZnO, and multi-walled carbon nanotubes (MWCNTs) through mechanical mixing to create a composite material called zinc methacrylate (ZDMA)/MWCNTs/rubber. The research investigates the in-situ synthesis mechanism of MAA and ZnO and the synergistic mechanism of ZDMA and MWCNTs. The study analyzes the impact of MWCNTs additive amount on the frictional wear of the internal mixer's metal end face. During the mixing process, ZDMA is grafted and polymerized onto rubber's macromolecular chains, forming ionic pairs with strong electrostatic interactions, creating a primarily reversible supramolecular network dominated by ion crosslinking. This ion crosslinking network, along with the three-dimensional mesh structure of MWCNTs, establishes a stable spatial structure within the rubber matrix. The study reveals that increasing the MWCNTs content to 3 phr reduces the aggregation of SiO 2 particles and ZDMA granules within the rubber matrix, resulting in reduced friction coefficients, roughness, and wear rates of the metal. However, exceeding 3 phr of MAA content leads to excessive MWCNT aggregation within the rubber matrix, increasing wear rates, roughness, and friction coefficients due to hindrance of rubber macromolecular chain crosslinking and reduced SiO 2 particle dispersion within the rubber matrix. These findings provide valuable insights into the dynamics of frictional wear in internal mixers. • Continuous mixer use erodes end faces, widens gaps, and hampers rubber performance. • Adding dynamic covalent bonds to rubber enhances self-repair, extending lifespan and cutting production costs. • MAA, ZnO, and MWCNTs create ZDMA/MWCNTs/rubber, studied for frictional wear impact. • Elevated MWCNTs levels (up to 3 phr) lower wear rates, roughness, and friction in rubber. • Excessive MAA (> 3 phr) increases wear, roughness, and friction by blocking crosslinking and reducing dispersion. [ABSTRACT FROM AUTHOR]

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]

Perhydropolysilazane (PHPS) is an inorganic polymer composed of -(SiH 2 –NH)- repeating structural units. When used as a coating material, it has the advantages of good solubility, simple curing conditions, flexible curing process, and simple preparation method and can significantly save processing time and cost. This paper investigates the frictional behavior of the PHPS-coated metals cured at different temperatures with NR/BR/SBR composites. The effects of different curing temperatures on the PHPS coatings are characterized using infrared absorption spectroscopy. After curing, the asymmetric stretching and oscillating vibration peaks of the Si–O–Si groups are formed, which is attributed to the hydrolysis reaction of Si–N and Si–H and the subsequent cross-linking curing reaction. The denseness of PHPS coatings increases with the increase in curing temperature. When the curing temperature is 400 °C, the cross-linking curing effect of PHPS is the strongest, and the denseness of the PHPS coating is the best. Furtherly, the frictional wear of metal with NR/BR/SBR composites is analyzed from the perspective of the formulation process for the first time, and the ratio of abrasive wear and corrosion wear is calculated qualitatively. It is found that increasing the curing temperature of the PHPS coating can significantly reduce metal wear and improve corrosion resistance, which is attributed to the formation of the ethanol-water molecular film on the surface of the PHPS coating. The ethanol-water molecular film isolates the contact between the PHPS-coated metal and the NR/BR/SBR composite to a certain extent, acting as a lubricant and thus reducing friction. After rubbing the cured PHPS-coated metal with NR/BR/SBR composite, the wear amounts of the cured PHPS-coated metal at 200 °C, 300 °C, and 400 °C are reduced by 49.06%, 66.74%, and 87.33%, respectively, and the corrosion resistance are improved by 51.52%, 63.64%, and 78.79%, respectively. • The friction behaviour of silicone-coated metal and rubber composites cured at different temperatures was investigated. • The metal wear of the coating cured at 300℃ is reduced by 66.74%, and the corrosion resistance is increased by 63.64%. • After curing at 400℃, the metal wear is reduced by 87.33%, and the corrosion resistance is increased by 78.79%. [ABSTRACT FROM AUTHOR]

• In this study, based on the viscoelastic solid theory of the rubber mixing process and the friction mechanism between rubber and metal, combined with the discrete element method, a dynamic simulation model for the wear of the synchronous quadrilateral rotor of an internal mixer is established. • The simulation results are compared under different mixing parameters. Analysis is performed, and a control experiment is set up to verify the feasibility of the discrete element software (EDEM) rotor wear dynamic simulation model. As the core component of an internal mixer, the rotor is subjected to friction from rubber and its filler during the mixing process, which causes the surface of the rotor to wear and can also affect the gap between the rotor edges as well as the gap between the rotor and the mixing chamber wall. The more significant the rotor wear, the larger the gap between the rotor ribs and the wall of the mixing chamber, which results in weaker shearing effect of the rotor on the rubber and even leads to uneven dispersion of filler in the rubber, eventually affecting the mixing effect and mixing quality of the glue. In this study, based on the viscoelastic solid theory of the rubber mixing process and the friction mechanism between rubber and metal, combined with the discrete element method, a dynamic simulation model for the wear of the synchronous quadrilateral rotor of an internal mixer is established. The simulations are performed in the EDEM software, and the results are analyzed and compared under different mixing parameters. Further, a control experiment is established to verify the feasibility of the proposed dynamic model for rotor wear. [ABSTRACT FROM AUTHOR]

As the essential mixing equipment, long hours of work can cause wear and tear on the end face of the compactor. The wear of the end faces leads to an increase in the gap between the chamber and the end faces, which leads to leakage, reduces the mixing effect, and ultimately affects the rubber properties. Therefore, it is necessary to study the end face metal wear during the mixing process. Thermally cracked carbon black, as recycled material for scrap rubber, can be used as a substitute for other carbon blacks in some fields, vastly reducing the production cost and promoting the reuse of scrap rubber. In this paper, thermally cracked carbon black (CBp) was mixed with multi-walled carbon nanotubes (MWCNTs) and added rubber by mechanical blending to obtain CBp/MWCNTs composites. The synergistic mechanism of CBp and MWCNTs was investigated to analyze the effect of CBp/MWCNTs ratios on the frictional wear of metal on the end face of the compactor. The results showed that MWCNTs cooperated with CBp particles to form a three-dimensional "grape bunch" network structure. On the one hand, the three-dimensional "grape bunch" network structure can adsorb CBp particles to promote the dispersion of CBp particles. On the other hand, the three-dimensional "grape bunch" network structure can also hinder the overflow of aromatic oil and affect oil film formation. At the same time, the three-dimensional "grape bunch" network structure can also form a physical isolation layer between the rubber and the metal. This significantly influences the degree of CBp particle dispersion, friction coefficient, metal surface roughness, and metal wear. It seems that the synergistic effect between MWCNTs and CBp particles is maximized when the content of MWCNTs in CBp/MWCNTs composites is 4 phr, the area of CBp/MWCNTs three-dimensional mesh is maximized, the dispersion of CBp particles is the best, and the wear of CBp/MWCNTs composites on metal is the lowest. • As the essential mixing equipment, long hours of work can cause wear and tear on the end face of the compactor. • The effect of the synergistic effect of CBp and MWCNTs on the friction and wear of end-face metal was analyzed. • The results showed that MWCNTs cooperated with CBp particles to form a three-dimensional "grape bunch" network structure. [ABSTRACT FROM AUTHOR]

As an essential rubber mixing equipment in continuous production, an internal mixer should have a long service life while operating at high intensity. Studies show that at these severe operating conditions, end face wear of the internal mixer is inevitable. It is worth noting that the end face is an important part of the closed mixing chamber. The head of the rotor shaft is inserted into the copper ring of the sealing plate, the sealing plate and the mixing chamber are pressed together by bolts. There is a gap between the rotors and the mixing chamber. During the mixing process, the mixed rubber in the mixing chamber is in direct contact with the end face, the end face metal is frictional and abraded. Wear of the end face may result in a gap between the mixing chamber and the end face, leading to material leakage. As the leakage intensifies, the gap between the end face and the mixing chamber further increases, thereby forming negative feedback. This phenomenon not only affects the chemical composition of the rubber but also reduces the mixing efficiency and decreases the performance of the rubber compound. The end surface material is cobalt chromium molybdenum tungsten alloy. The alloy model is Stellite 6B. In the present study, the influence of different amounts of CF on the friction and wear of the end face is analyzed from the chemical composition perspective. Moreover, the ratio of corrosion wear to abrasive wear is calculated. The obtained results show that as the amount of CF in the compound increases, the proportion of the corrosive wear of the compound to the metal increases, while the proportion of abrasive wear decreases. The highest proportion of corrosive wear and the lowest amount of metal wear can be achieved for the CF amount of 9 phr. As the CF content in the composition increases, the ratio of the corrosive wear of the rubber compound to metal decreases, while the proportion of abrasive wear and the total amount of wear to metal increases. • Studies show that at these severe operating conditions, end seal wear of the internal mixer is inevitable. • This study analyzed the effect of different additions of CF on the friction and wear of the end seal. • The highest proportion of corrosive wear and the lowest amount of metal wear can be achieved for the CF amount of 9 phr. [ABSTRACT FROM AUTHOR]

Internal mixer is an important mixing component in industrial applications. Studies show that when a mixer operates for a long time, wear may appear at the end face of the internal mixer. On the other hand, abrasion of the end face increases the gap between the mixing chamber and the end face. Then, leakage occurs, which reduces the mixing effect and affects the rubber performance. Therefore, it is of significant importance to study the wear of the end face during the mixing process. Graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) have excellent electrical characteristics and thermal conductivity so that they have been widely used in various fields such as synthesized composite rubbers. GO and MWCNTs are mechanically blended into natural rubber to obtain GO/MWCNTs composite material. In the present study, the influence of the GO/MWCNTs ratio on the friction and wear of the end face of the internal mixer is analyzed. The obtained results show that MWCNTs and GO molecules interact to form a three-dimensional network structure, which has a greater impact on the degree of silica dispersion, silanization reaction, and metal wear. As the GO content increases, the average friction coefficient between rubber and metal, metal roughness, the proportion of abrasive wear, and the amount of metal wear gradually decrease. The lowest values can be achieved when the amount of added GO is set to 3 phr. When the GO in the mixture exceeds 3 phr, the friction coefficient between rubber and metal, and the metal roughness change, thereby affecting the proportion of abrasive wear and increasing the amount of metal wear in the mixing process. In this experiment, the amount of CNT that reduces GO aggregation is 6 phr. On the whole, when the ratio of GO/MWCNTs is 3/6, the synergistic effect of MWCNTs and GO molecules is maximized, the area of the three-dimensional network structure of GO/MWCNTs is the largest, the dispersibility of SiO 2 is the best, and the amount of wear of the composite material on the metal is the lowest. • In the present study, the influence of the GO/MWCNTs ratio on the friction and wear of the end face of the internal mixer is analyzed. • The obtained results show that MWCNTs and GO molecules interact to form a three-dimensional network structure. • It is concluded that the metal wear is minimized when the ratio of GO/MWCNTs in the GO/MWCNTs composite is set to 3/6. [ABSTRACT FROM AUTHOR]

As the basic equipment in the rubber field, the internal mixer is suitable for long-term rubber mixing. For the continuous production of the factory, the wear of the internal mixer is a problem that cannot be ignored. This article mainly studies the wear of the end face of the internal mixer. The end face of the mixer is connected to the mixing chamber. With the increase in mixing time, the end face of the mixer is inevitably worn. The abrasion of the end face of the internal mixer causes the gap between the end face of the internal mixer and the mixing chamber to increase, and the materials in the mixing chamber leak out. This affects the ratio of materials and reduces the mixing effect. And with the increase in material leakage, the abrasion of the end face of the internal mixer is intensified, which eventually leads to a decrease in the compound's performance. BF is a pure natural inorganic non-metallic material. It has good high-temperature resistance, and high compressive strength can be used in various environments and is inexpensive and cost-effective. Based on this, BF is increasingly used in the rubber field. In this paper, the effect of adding different amounts of BF on the friction and wear of the end face of the internal mixer is studied, and the proportions of varying wear forms are distinguished for the first time. The study finds that with the increase of BF in the compound, the proportion of abrasive wear first decreased and then increased, the balance of corrosion wear first increased and then decreased, and the amount of metal wear first decreased and then increased. It is found that the lowest wear of the rubber compound on the metal can be achieved when the amount of BF reaches 10 phr. When the BF amount increases, the corresponding amount of metal wear increases. • With the increase of mixing time, the end face of the mixer is inevitably worn. • This paper studied the effect of different BF additions on the friction and wear of metals. • It is found that the lowest wear of the rubber compound on the metal can be achieved when the amount of BF reaches 10 phr. [ABSTRACT FROM AUTHOR]