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As a piece of high-intensity running equipment, the wear of an internal mixer determines the quality of rubber and its life. In general, the wear of an internal mixer is caused by the friction between the rubber and metal during the mixing process, and the most severe wear position is the end face of the equipment. In this paper, a mixture of multi-walled carbon nanotubes (MWCNTs) and carbon fibers (CFs) are added to rubber by mechanical compounding to obtain MWCNT/CF/carbon black (CB) composites. By investigating the synergistic mechanism of MWCNTs and CFs, we analyze the effect of the MWCNT/CF ratio on the frictional wear of metal on the end face of the internal mixer. At the microscopic level, MWCNTs and CFs form a spatial meshwork with CB particles through synergistic interactions. The CB particles can be adsorbed on the spatial meshwork to promote the dispersion of CB particles. In addition, the formation of oil film can be slowed down due to the spatial meshwork, which could hinder the spillage of aromatic oil. Meanwhile, the spatial meshwork serves as a physical isolation layer between the rubber and metal to reduce friction. Therefore, it dramatically impacts the dispersion degree of CB particles, the friction coefficient, the roughness of the surface, and the wear of metal. It shows that the synergistic effect of MWCNT/CF and CB particles is best when the CF content of the rubber matrix is 5 phr, showing the most stable spatial network structure, the best dispersion of CB particles, and minor wear on the end face of the internal mixer. [ABSTRACT FROM AUTHOR]

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]

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]

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]