CRACK GROWTH BEHAVIOR OF STYRENE-BUTADIENE RUBBER, NATURAL RUBBER, AND POLYBUTADIENE RUBBER COMPOUNDS: COMPARISON OF PURE-SHEAR VERSUS STRIP TENSILE TEST

2013 ◽  
Vol 86 (1) ◽  
pp. 132-145 ◽  
Author(s):  
G. Andreini ◽  
P. Straffi ◽  
S. Cotugno ◽  
G. Gallone ◽  
G. Polacco

ABSTRACT Fatigue crack growth experiments on different carbon black–filled rubber compounds have been carried out to evaluate the influence of pure-shear and strip tensile testing mode by using sine and pulse as waveforms. In a previous set of experimental investigations regarding the influence of both waveform and tested material, it was found that the mode I of crack opening sometimes propagates too quickly to be properly monitored in tests involving strip-tensile specimens. An alternative test methodology based on pure-shear test mode has been investigated, optimizing both the shape of the specimen and the test equipment. Data obtained from the different compound formulations were consistent with the theoretical background and resulted in similar ranking of compound crack growth resistance for the two testing modes; in addition, pure-shear mode showed a higher sensitivity to formula variations.

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 270 ◽  
Author(s):  
Sankar Raman Vaikuntam ◽  
Eshwaran Subramani Bhagavatheswaran ◽  
Fei Xiang ◽  
Sven Wießner ◽  
Gert Heinrich ◽  
...  

The article focuses on comparing the friction, abrasion, and crack growth behavior of two different kinds of silica-filled tire tread compounds loaded with (a) in-situ generated alkoxide silica and (b) commercial precipitated silica-filled compounds. The rubber matrix consists of solution styrene butadiene rubber polymers (SSBR). The in-situ generated particles are entirely different in filler morphology, i.e., in terms of size and physical structure, when compared to the precipitated silica. However, both types of the silicas were identified as amorphous in nature. Influence of filler morphology and surface modification of silica on the end performances of the rubbers like dynamic friction, abrasion index, and fatigue crack propagation were investigated. Compared to precipitated silica composites, in-situ derived silica composites offer better abrasion behavior and improved crack propagation with and without admixture of silane coupling agents. Silane modification, particle morphology, and crosslink density were identified as further vital parameters influencing the investigated rubber properties.


Author(s):  
A Hamdi ◽  
A Boulenouar ◽  
N Benseddiq

No unified stress-based criterion exists, in the literature, for predicting the rupture of hyperelastic materials subjected to mutiaxial loading paths. This paper aims to establish a generalized rupture criterion under plane stress loading for elastomers. First, the experimental set up, at breaking, including various loading modes, is briefly described and commented. It consists of uniaxial tests, biaxial tests and pure shear tests, performed on different rubbers. The used vulcanizate and thermoplastic rubber materials are a Natural Rubber (NR), a Styrene Butadiene Rubber (SBR), a Polyurethane (PU) and a Thermoplastic elastomer (TPE). Then, we have investigated a new theoretical approach, based upon the principal stresses, to establish a failure criterion under quasi-static loadings. Thus, we have proposed a new analytical model expressed as a function of octahedral stresses. Quite good agreement is highlighted when comparing the ultimate stresses, at break, between the experimental data and the prediction of the proposed criteria using our rubber-like materials.


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

1999 ◽  
Vol 35 (9) ◽  
pp. 1687-1693 ◽  
Author(s):  
N.S. Saxena ◽  
P. Pradeep ◽  
G. Mathew ◽  
S. Thomas ◽  
M. Gustafsson ◽  
...  

2010 ◽  
Vol 83 (1) ◽  
pp. 97-122 ◽  
Author(s):  
Xiao-Dong Pan ◽  
Paul Zakelj ◽  
Cara Adams ◽  
Akiko Neil ◽  
Greg Chaplin

Abstract The British pendulum skid tester (BPST) has been widely adopted for laboratory characterization of wet skid resistance (WSR) for rubber compounds. However, testing results are not yet well explained with material properties. For filled compounds made of the same styrene-butadiene rubber, on a Portland cement concrete surface wetted with water, WSR for compounds filled with inorganic oxides is higher than WSR for compounds filled with carbon black at the same filler volume fraction. However, such difference in WSR is eliminated under ethanol lubrication. Difference in WSR remains under ethanol lubrication between compounds filled with a reinforcing filler and compounds filled with a nonreinforcing filler. Accepting that dynamic deformation of rubber occurs in the frequency range between 103 and 106 Hz during testing with the BPST, loss tangent for the compounds is measured at various low temperatures but fails to correlate with WSR detected under water lubrication. Modification of bulk viscoelasticity from ethanol absorption should not be neglected for consideration of WSR under ethanol lubrication. During testing with the BPST, sliding noise generated by the assemblage of the spring and lever system in the pendulum with a rubber slider attached is captured under varied lubrication conditions. Both viscoelastic properties of rubber compounds and lubrication condition significantly affect sliding noise. However, no strict correlation between the intensity of sliding noise and WSR is observed. From frequency domain analysis, major components of the sliding noise lie in the frequency range between 500 and 5000 Hz for most compounds. For better understanding on testing with the BPST, modes of material deformation during dynamic sliding on a wet rough surface need to be further scrutinized.


Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 767 ◽  
Author(s):  
Dániel Simon ◽  
István Halász ◽  
József Karger-Kocsis ◽  
Tamás Bárány

Because of the chemically crosslinked 3D molecular structure of rubbers, their recycling is a challenging task, especially when cost efficiency is also considered. One of the most straightforward procedures is the grinding of discarded rubber products with subsequent devulcanization. The devulcanized rubber can be used as a feedstock for fresh rubber compounds or can be blended with uncured virgin rubber and thermoplastic polymers to form thermoplastic dynamic vulcanizates (TDVs). TDVs combine the beneficial (re)processability of thermoplastics and the elastic properties of rubbers. Our current work focuses on the development of polypropylene (PP)-based TDVs with the use of a tire model rubber (MR) composed of natural rubber (NR) and styrene-butadiene rubber (SBR) in a ratio of 70/30. The research target was the partial substitution of the above fresh MR by microwave devulcanized crumb rubber (dCR). TDVs were produced by continuous extrusion, and the effects of composition (PP/MR/dCR = 40/60/0…50/35/15) and processing parameters (different screw configurations, temperature profiles, the feeding method of PP) were investigated. Results showed that the fresh rubber compound can be replaced up to 10 wt % without compromising the mechanical properties of the resulting TDV.


2019 ◽  
Vol 92 (1) ◽  
pp. 25-42 ◽  
Author(s):  
Akshata Kulkarni ◽  
Coleen Pugh ◽  
Sadhan C. Jana ◽  
Darnell T. Wims ◽  
Ammar Abdel Gawad

ABSTRACT This research investigates the potential of benzocyclobutene (BCB) chemistry for crosslinking styrene-butadiene rubber in conjunction with sulfur curatives with the objective of achieving curing at lower temperatures and/or in shorter times compared with entirely sulfur-based cure formulations. The reversible polysulfidic linkages produced in sulfur crosslinking allow self-healing characteristics but suffer from poor heat-aging stability. The C–C crosslinks from BCB chemistry are irreversible and offer higher resistance to aging, but they do not present apparent self-healing properties. The hybrid curative package based on C–C, C–S, and S–S linkages developed is expected to provide reduced crosslinking time and/or temperature, along with higher crack-growth resistance, the ability to self-heal, higher resistance to fatigue-to-failure, reduced hysteresis, and increased abrasion resistance. The crosslinking performance of 1-substituted BCB-based compounds in conjunction with sulfur is specifically investigated.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1723 ◽  
Author(s):  
Magdalena Maciejewska ◽  
Anna Sowińska ◽  
Judyta Kucharska

Organic zinc salts and complexes were applied as activators for sulfur vulcanization of styrene–butadiene elastomer (SBR) in order to reduce the content of zinc ions in rubber compounds as compared with conventionally used zinc oxide. In this article, the effects of different organic zinc activators on the curing characteristics, crosslink densities, and mechanical properties of SBR as well as the aging resistance and thermal behavior of vulcanizates are discussed. Organic zinc salts seem to be good substitutes for zinc oxide as activators for sulfur vulcanization of SBR rubber, without detrimental effects to the vulcanization time and temperature. Moreover, vulcanizates containing organic zinc salts exhibit higher tensile strength and better damping properties than vulcanizate crosslinked with zinc oxide. The application of organic zinc activators allows the amount of zinc ions in SBR compounds to be reduced by 70–90 wt % compared to vulcanizate with zinc oxide. This is very important for ecological reasons, since zinc oxide is classified as being toxic to aquatic species.


2010 ◽  
Vol 83 (4) ◽  
pp. 391-403 ◽  
Author(s):  
G. Andreini ◽  
P. Straffi ◽  
S. Cotugno ◽  
G. Gallone ◽  
G. Polacco

Abstract Fatigue crack growth experiments on carbon black-filled rubber compounds have been carried out to evaluate the influence of testing conditions over different compound formulations. Investigations on the influence of waveform, data acquisition, and compound formulation have been performed on strip-tensile specimens reproducing the mode I of crack opening. The response of three different compound formulations (based on either natural rubber, butadiene rubber, or styrene-butadiene rubber) to the application of two different waveforms, pulse and sine, has been analyzed, showing significant differences in fatigue behavior and ranking of the various compounds. Compared to the sinusoidal waveform, the use of a pulse waveform provided an improved correlation of the tearing energy with the crack propagation speed. This difference was particularly evident in the case of natural rubber and butadiene rubber, while it resulted negligible in the case of styrene-butadiene rubber. Such a different behavior could be attributed to differences in macromolecular chains orientation. Fine-tuning of video acquisition parameters provided an accurate observation of the crack growth process, as confirmed by the low standard deviation of the estimated tearing energy and crack growth rate.


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