scholarly journals Compressive Fatigue Behavior of Gum and Filled SBR Vulcanizates

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1497
Author(s):  
Liu Yang ◽  
Lin Wang ◽  
Huaiqing Guo ◽  
Aihua Du

The influence of carbon black on physical mechanical properties, compressive fatigue life, and the temperature changes during compression fatigue process of styrene-butadiene rubber (SBR) vulcanizates were explored. A series of unfilled and filled SBR compounds were prepared, and the compressive fatigue behaviors of the vulcanizates were performed on a mechanical testing and simulation (MTS) machine. The top surfaces of the filled SBR were imaged using scanning electron microscopy (SEM) after 105 cycles of compressive fatigue. The filled SBR shows greater compressive fatigue resistance than the unfilled SBR. The incorporation of carbon black into SBR improves the creep resistance. The best compressive fatigue resistance for the filled SBR was achieved by the addition of 30 phr carbon black. With the increase of carbon black content, the energy dissipation and the heat build-up increase simultaneously. Furthermore, SEM images of the vulcanizates suggest that the crack propagation mechanism of the unfilled and the filled SBR was different. For the unfilled SBR, due to periodical compressive stress, the polymer chains can be destroyed, and the cracks can be easily initiated and propagated, showing serious damage on the top surfaces of the specimen. However, for the filled SBR, the carbon black agglomeration around the cracks can greatly delay the generation of the cracks, decrease the fatigue damage, and ultimately improve the fatigue resistance.

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Liu Yang ◽  
Kaikai Liu ◽  
Aihua Du

The effect of network structure on dynamic compressive fatigue behavior and static compressive mechanical properties of styrene-butadiene rubber (SBR) were investigated. A series of SBR compounds with different amounts of sulfur and dicumyl peroxide (DCP) were prepared, and their crosslinking densities were calculated using the Flory–Rehner equation. Compressive fatigue resistance and creep behavior of the vulcanizates were performed on a mechanical testing and simulation (MTS) machine. The fatigue damage surface of SBR vulcanizates before and after a dynamic compressive fatigue test was observed with a scanning electron microscopy (SEM). The results suggested that the surface of the samples was badly damaged as the number of compressive cycles increased. By comparison, compressive fatigue caused less surface damage to sulfur-cured SBR than to peroxide-cured SBR. The peroxide-cured SBR samples showed higher energy dissipation than sulfur-cured SBR during cyclic compression. The peroxide-cured SBR showed lower creep strain and compression set than the sulfur-cured SBR. The -Sx- linkages provided by the sulfur curing system allow dynamic compressive deformation but suffer from poor static compressive resistance. However, the carbon-carbon linkages from DCP are irreversible and provide higher resistance to static compressive stress, but they do not show obvious dynamic compressive fatigue resistance.


2020 ◽  
Vol 39 (1) ◽  
pp. 81-90
Author(s):  
An Zhao ◽  
Xuan-Yu Shi ◽  
Shi-Hao Sun ◽  
Hai-Mo Zhang ◽  
Min Zuo ◽  
...  

2012 ◽  
Vol 19 (01) ◽  
pp. 1250003
Author(s):  
JIAN CHEN ◽  
YONGZHONG JIN ◽  
JINGYU ZHANG ◽  
YAFENG WU ◽  
CHUNCAI MENG

Bound rubber in carbon black (CB) filled rubber (natural rubber (NR) and styrene–butadiene rubber (SBS)) was prepared by the solvent method. The nanomorphology of CB and rubber/CB soluble rubber was observed by atomic force microscope. The results show that high-structure CB DZ13 has a "grape cluster" structure which consists of many original particles with the grain size of about 30–50 nm. Graphitizing process of CB decreases the amount of bound rubber. The NR/DZ13 soluble rubber with island–rim structure has been obtained, where the islands are DZ13 particles and the rims around the islands are occupied by NR film. But when the graphitized DZ13 particles were used as fillers of rubber, we have only observed that some graphitized DZ13 particles were deposited on the surface of the globular-like NR molecular chains, instead of the spreading of NR molecular chains along the surface of DZ13 particles, indicating that graphitized DZ13 has lower chemical activity than ungraphitized DZ13. Especially, we have already observed an interesting unusual bound rubber phenomenon, the blocked "bracelet" structure with the diameter of about 600 nm in which CB particles were blocked in ring-shaped SBS monomer.


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