EFFECT OF CURING ADDITIVES ON THE DISPERSION KINETICS OF CARBON BLACK IN RUBBER COMPOUNDS)

2011 ◽  
Vol 84 (3) ◽  
pp. 415-424 ◽  
Author(s):  
H. H. Le ◽  
S. Ilisch ◽  
E. Hamann ◽  
M. Keller ◽  
H-J. Radusch

Abstract The effect of curing additives on the dispersion kinetics of carbon black (CB) in styrene butadiene rubber (SBR) compounds was investigated by means of the method of the online measured electrical conductance. Addition of curing additives such as stearic acid and diphenylguanidine (DPG) accelerates the CB dispersion process significantly. The viscosity of the rubber matrix was not changed after their addition. The addition of stearic acid and DPG may alter the filler–filler interaction that consequently leads to faster dispersion processes. The obtained difference in morphologies of SBR mixtures containing stearic acid and DPG, respectively, are caused by their different infiltration behavior, which may lead to different dispersion mechanisms. Addition of ZnO could not improve the dispersion process of CB because of its limited interaction with CB. Sulfur and N-cyclohexylbenzothiazole-2-sulfenamide decelerate the CB dispersion process. The strong effect of the rubber microstructure such as styrene content and molecular weight on the CB dispersion in SBR mixtures without additives was found and discussed by taking into consideration the known dispersion mechanisms. The influence of addition of curing additives on the CB dispersion in low styrene-content SBR mixtures is much more pronounced than that in high styrene-content SBR mixtures.

1970 ◽  
Vol 43 (6) ◽  
pp. 1349-1358 ◽  
Author(s):  
B. G. Corman ◽  
M. L. Deviney ◽  
L. E. Whittington

Abstract Migration of oils, curatives, antioxidants, and other compounding materials in a vulcanized rubber matrix is a general phenomenon. A continuing, long range program has been undertaken in these laboratories to understand better this effect, in order that ultimately the compounder can predict, from a knowledge of the molecular nature of the penetrant and the physico-chemical properties of the cured matrix, the distribution of the various components during the service life of the finished rubber product. A sensitive radiotracer approach with earbon—14 is being used to study this system. Earlier work in this program has established the general value of the diffusion coefficient for whole paraffinic oils and for aromatic oils and their fractions. In general, this has shown that moderate variations in the molecular composition of the aromatic portions of the oils have only minor effects on these migration rates. Using similar computer derived diffusion coefficients, the current data indicate that naphthenic molecules migrate at equal to slightly higher rates than aromatic molecules of similar boiling points. Thermal diffusion as a mode of separation of the oil gives fractions showing more selectivity (larger differences in migration rates) than the formerly used silica gel procedures. Variations in carbon black type and loading levels have no detectable effect on migration. The most important factor in diffusion is the polymer matrix, which for the oils studied is in the order : polybutadiene (D≃6.4×10−7 cm2 sec−1 at 100° C), natural rubber (D≃3.5×10−7 cm2 sec−1), ethylene-propylene-diene rubber (D≃2.6×10−7 cm2 sec−1) and styrene—butadiene rubber (D≃1.9×10−7 cm2 sec−1). Activation energies for the diffusion process were PBR, 3.1 ; NR, 7.8; EPDM, 10.3; and SBR, 9.9 (energies in kilocalories per mole).


2020 ◽  
pp. 096739112090288
Author(s):  
Sun-Mou Lai ◽  
Yun-Lan Chu ◽  
Yu Ting Chiu ◽  
Ming-Chi Chang ◽  
Tung-Yuan Hsieh ◽  
...  

Only a few works focus on the use of commercial pyrolysis carbon black (PCB) to replace with commodity carbon black in terms of increasing environmental awareness. In this work, a commercial PCB (ET (Enrestec) black) from waste tires was compared with N660 carbon black in styrene–butadiene rubber (SBR) compounds using standard American Society for Testing and Materials recipes. Particle aggregate size, composition, and surface functionality of ET black and N660 were analyzed through light scattering, energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy, respectively. Higher compound viscosity and aggregation power for ET black filler in the rubber matrix was observed. A progressive decrement of approximately 20% in M300 from 15.2 MPa for N660-filled SBR to 12.4 MPa for ET black-filled SBR with increasing ET black ratio in the fillers was clearly observed. ET black could potentially replace 20% in N660 without much influence for SBR compounds in terms of tensile strength. The effect of ET black content on the tear strength was less marginal than the tensile strength. However, with increasing the ET black content, the abrasion resistance index progressively decreased. Thus, it was quite beneficial to consider the merit of PCB in terms of the applications required for tearing resistance. This paves the way for the opportunities to expand further commercial application of PCB from waste tires in the light of environmental awareness.


2017 ◽  
Vol 44 (3) ◽  
pp. 19-24
Author(s):  
A.R. Mukhtarov ◽  
A.M. Mokhnatkin ◽  
V.P. Dorozhkin ◽  
E.G. Mokhnatkina ◽  
V.E. Muradyan ◽  
...  

The processing and mechanical properties of green and vulcanised tread rubbers based on a blend of two types of styrene butadiene rubber filled with carbon black and containing single-layer carbon nanotubes (SCNTs) were studied. Three types of rubber mix were prepared: one containing untreated SCNTs and stearic acid, and two with SCNTs treated by different methods. The properties of these composites were compared. In all cases, the introduction of SCNTs leads to an increase in the cohesion strength of green rubber mixes, to an improvement in their vulcanisation properties, and to an increase in the Mooney viscosity, and also to an improvement in the dynamic properties of the vulcanisates, and here the Payne effect increases. There is also an improvement in the wear resistance, especially in the case of introducing untreated SCNTs and stearic acid which ensures the presence of –COOH groups.


Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2413
Author(s):  
Mariapaola Staropoli ◽  
Vincent Rogé ◽  
Enzo Moretto ◽  
Joffrey Didierjean ◽  
Marc Michel ◽  
...  

The improvement of mechanical properties of polymer-based nanocomposites is usually obtained through a strong polymer–silica interaction. Most often, precipitated silica nanoparticles are used as filler. In this work, we study the synergetic effect occurring between dual silica-based fillers in a styrene-butadiene rubber (SBR)/polybutadiene (PBD) rubber matrix. Precipitated Highly Dispersed Silica (HDS) nanoparticles (10 nm) have been associated with spherical Stöber silica nanoparticles (250 nm) and anisotropic nano-Sepiolite. By imaging filler at nano scale through Scanning Transmission Electron Microscopy, we have shown that anisotropic fillers align only in presence of a critical amount of HDS. The dynamic mechanical analysis of rubber compounds confirms that this alignment leads to a stiffer nanocomposite when compared to Sepiolite alone. On the contrary, spherical 250 nm nanoparticles inhibit percolation network and reduce the nanocomposite stiffness.


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