# Natural Rubber/Styrene-Butadiene Rubber Blend Composites Potentially Applied in Damping Bearings
###### Abstract  
Natural rubber (NR) composites have been widely applied in damping products to reduce harmful vibrations, while rubber with only a single composition barely meets performance requirements. In this study, rubber blend composites including various ratios of NR and styrene butadiene rubber (SBR) were prepared via the conventional mechanical blending method. The effects of the rubber components on the compression set, compression fatigue temperature rising and the thermal oxidative aging properties of the NR/SBR blend composites were investigated. Meanwhile, the dynamic mechanical thermal analyzer and rubber processing analyzer were used to characterize the dynamic viscoelasticity of the NR/SBR blend composites. It was shown that, with the increase in the SBR ratio, the vulcanization rate of the composites increased significantly, while the compression fatigue temperature rising of the composites decreased gradually from 47 \({}^{\circ}\)C (0% SBR ratio) to 31 \({}^{\circ}\)C (50% SBR ratio). The compression set of the composites remained at \(\sim\)33% when the SBR ratio was no more than 20%, and increased gradually when the SBR ratio was more than 20%. n natural rubber; styrene-butadiene rubber; compression set; compression fatigue temperature rising; thermal oxidative aging; damping +
Footnote †: journal:  
00 2024 16 1945 10.1007/10/00000-0000-00000-00000-00000-00000-00000-0000-00000-00000-00000-00000-00000-000000-000000-000000-000000-000000-000000-0000000-000000-0000000-0000000-0000000-0000000-0000000-0000000-000  
variety. The particle size and the amount of carbon black added can significantly affect the mechanical properties of the rubber composite. N330 and N774 are two commonly used rubber fillers. N330 (high abrasion furnace black; HAF) is a carbon black with good reinforcing properties that can enhance the tensile properties, tear resistance, abrasion resistance and elasticity of the rubber composite. However, large amounts of N330 will significantly increase the compression set and compression fatigue temperature rising of the rubber composite, due to the small particle size of N330 carbon black. Therefore, in practice, it is necessary to use a portion of the larger particle size carbon black to meet the reinforcing effect of the rubber composite and reduce the compression set and compression fatigue temperature rising at the same time. For rubber vibration damping bearings applied in engineering, the main failure causes of the bearings are the cracking and permanent deformation of the rubber material. Therefore, rubber composites for vibration damping require high-performance in compression set, compression fatigue temperature rising and mechanical properties in addition to the damping properties [19; 20]. There have been many studies dealing with NR vibration damping composites. [PERSON] et al. [21] developed a new processing method to prepare quaternary layered gradient composites by laminating NR and three types of ENR (epoxidation: 25%, 40% and 50%) in a certain order. The peak value of tan delta (tan \(\delta\)) for the composites was up to 1.815 when the number of plies reached 32, with an effective damping temperature range of 69.7 \({}^{\circ}\)C from \(-\)24.8 \({}^{\circ}\)C to 44.9 \({}^{\circ}\)C (tan \(\delta>0.3\)). [PERSON] et al. [22] prepared natural rubber/hindered phenolic/styrene-isoprene block copolymer (NR/AO-80/SIS) composites. NR/AO-80/SIS were made of hindered phenolic polar small molecules (AO-80) and styrene-isoprene block copolymer (SIS) as damping performance enhancement components. They investigated the effects of SIS and AO-80 on the morphology, structure, mechanical properties, aging resistance and damping properties of NR/AO-80/SIS composites. The effective damping temperature range extends to a maximum of 114.5 \({}^{\circ}\)C, indicating that SIS significantly improves the damping properties of NR/AO-80.