The function of silane coupling agent in rubber mixing field is to combine inorganic matrix with rubber organic matrix. Silica is commonly used in the rubber mixing field to strengthen rubber. The size and amount of silica aggregates in the mixing process are important factors affecting the wear of the mixing chamber. The wear of the mixing chamber would lead to a increasing gap between the mixer chamber and the rotor, which caused the mixing efficiency reducing. It also affected the dispersion effect, then affected the mechanical and physical properties of the vulcanized rubber. In this paper, the effects of rubber compound on metal friction and wear were studied by using four silane coupling agents commonly used in rubber mixing field. The experiment was carried out at 15 C, and the attention should be paid to drying during sample preparation to avoid the deviation of the experiment caused by hydrolysis of silane coupling agent. The results showed that silanization reaction occured between silica and silane coupling agent in the mixing process.The mixing temperature was usually maintained at 145 to 155 C for 1 min in the mixer, and the silanization reaction rate was the fastest during this time.We took this rubber compound as the research object and studied the friction and wear of the rubber compound on the mixing chamber in the mixing process. The products of the silylation reaction are alcohol and water. This paper studies the corrosion and abrasion of the mixing chamber by water at high temperatures. In the mixing process, abrasive wear was the main wear form, but the corrosion wear caused by high temperature steam still occupied a large proportion.
Studies show that long-term operation of the rubber mixer results in wear at the end face of the mixer. End face wear increases the gap between the mixing chamber and the end face, which results in leakage and reduces the mixing performance, thereby affecting the quality of the final product. Therefore, it is of significant importance to investigate the wear of metal face during the mixing process. In the present study, calcium powder was added to the rubber compound using a mechanical blender to obtain a composite material. Then the influence of the calcium powder on metal friction and wear of the end face of the mixer was analyzed. The obtained results show that the calcium powder has anti-friction properties, which can greatly reduce the compound wear on the metal. The lowest corrosion and wear of the compound on the metal was achieved with 5 phr of calcium powder. Meanwhile, it is found that the tensile and tear-resistance properties of the compound with 5 phr of calcium powder are slightly lower than those without calcium powder. However, the compound with 5 phr of calcium powder has higher friction, cold resistance, wet slip resistance, and lower rolling resistance.
Internal mixer is one the most commonly used rubber-mixing equipment, which has been applied for decades. This device can operate continuously for a long time. Accordingly, it is quite probable to have wear of the end face of the mixer. Studies show that the end face wear increases the gap between the mixing chamber and the end face, resulting in material leakage, reducing the mixing effect and ultimately affecting the properties of the compound. Therefore, it is of significant importance to study the friction and wear of the mixing compound to the metal in the mixing process. Considering the superior characteristics of graphene (GE), it is considered a revolutionary material and has been widely applied in numerous applications. In the present study, the influence of the mixing compound with different amounts of GE on the friction and wear of the metal end face was analyzed and the ratio of the corrosion wear to abrasive wear was calculated for the first time. It was found that as the amount of GE increases, the proportion of abrasive wear on the metal increases, the proportion of corrosive wear on the metal decreases, and the metal wear decreases first and then increases. Moreover, the lowest metal wear can be achieved when the amount of GE is 3 phr.
Carbon based materials with excellent conductivity such as conductive carbon black, graphene, and carbon nanotubes (CNTs) are often used in the preparation of conductive polymer composites. Pyrolysis carbon black, as a recycled material of waste rubber, can be used as a substitute for other carbon black in some fields, which can greatly reduce the production cost and promote reuse of used rubber. In this article, pyrolysis carbon black is mixed with CNT and added to natural rubber by mechanical blending method to get the composite material. The synergistic effect of pyrolysis carbon black and CNT, 3D network structure and formation of conductive network are investigated, and the properties of composites are analyzed. The results show that the 3D "grape cluster" network structure formed by the synergistic action of the pyrolysis carbon black and CNT, which led to the improvement of the curing properties and mechanical properties of the composites, increase the Payne effect, decrease the dispersion of the filler, and significant reduction the volume resistivity of the composites. With the increasing of CNT content, the variation of the properties of the composites changed and stabilized. In general, when 40 phr pyrolysis carbon black and 4 phr CNT are mixed into rubber matrix, the composite has the best comprehensive performance, and the volume resistivity is 9.25E5. Our results provide new thoughts in preparing natural rubber conductive composites. By adding highly CNT and inexpensive pyrolysis carbon black, the problem of easy aggregation of a single filler is overcome, which is more economical than adding two highly conductive fillers, and the process is simpler and time-saving compared to the modified solution. More studies need to be done in order to reveal the effects of pyrolysis carbon black in practical conductive composites. K E Y W O R D S3D "grape cluster" network structure, conductive composites, mechanical properties, pyrolysis carbon black, volume resistivity, vulcanization characteristic | INTRODUCTIONWith the rapid development of the information and electronics industry, the traditional metal conductive materials can no longer meet the existing demand, so the conductive polymer materials with excellent conductive properties began to be widely studied. [1][2][3][4] In actual production, by adding various nanofillers, the
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