Green Strength of Carbon-Black-Filled Styrene—Butadiene Rubber

1992 ◽  
Vol 65 (2) ◽  
pp. 475-487 ◽  
Author(s):  
P. L. Cho ◽  
G. R. Hamed
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
High Yield ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Green Strength ◽  
Strain And Strain Rate ◽  
Furnace Black ◽  
Reduced Rate ◽  
Styrene Butadiene

Abstract The green strengths of a gum SBR and two black-filled samples, at twenty-three volume percent filler, have been determined at various strain rates and temperatures. At higher temperatures, all samples exhibit yielding, followed by strain-softening. The gum exhibits this type of behavior down to −20°C, whereas, filled specimens undergo strain hardening at this temperature. Yield strength increases with decreasing temperature or increasing rate, indicating that it is largely controlled by chain mobility. Yield strengths at various temperatures may be shifted along the rate axis to form mastercurves. The dependence of yield stress on reduced rate is similar for the gum and the composition filled with the large-sized thermal black (N990). Stiffening is reasonably well accounted for by strain and strain-rate amplification, using the well-known Guth—Gold amplification factor. At low reduced rates, the extent of stiffening is substantially greater for samples filled with the much finer furnace black, N110. Unlike with the N990, SBR filled with N110 forms a coherent bound-rubber gel. This provides a strong resistance to deformation (beyond simple strain or strain-rate amplification) and results in high yield strength. At low temperatures, perhaps when the magnitude of chain—chain and chain—filler internal friction is comparable, the effect of filler size is greatly diminished.

Effect of Finite Extensibility on the Viscoelastic Properties of a Styrene-Butadiene Rubber Vulcanizate in Simple Tensile Deformations up to Rupture

1970 ◽  
Vol 43 (4) ◽  
pp. 714-734
Author(s):  
T. L. Smith ◽  
R. A. Dickie
Keyword(s):  
Strain Rate ◽  
Constant Strain Rate ◽  
Shift Factor ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Stress Strain ◽  
Temperature Function ◽  
Extension Ratio ◽  
Styrene Butadiene ◽  
Maximum Extensibility

Abstract Stress-strain and rupture data were determined on an unfilled styrene-butadiene vulcanizate at temperatures from −45 to 35° C and at extension rates from 0.0096 to 9.6 min−1. The data were represented by four functions: (1) the well-known temperature function (shift factor) aT; (2) the constant-strain-rate modulus, F (t, T) reduced to temperature T0 and time t/aT, i.e., T0F (t/aT)/T (3) the time-dependent maximum extensibility λm (t/aT); and (4) a function Ω(χ) where χ=(λ−1)λm0/λm, in which λ is the extension ratio and λm0 is the maximum extensibility under equilibrium conditions. The constant-strain-rate modulus characterizes the stress-time response to a constant extension rate at small strains, within the range of linear response; λm is a material parameter needed to represent the response at large λ; and Ω(χ) represents the stress-strain curve of the material in a reference state of unit modulus and λm=λm0. The shift factor aT was found to be sensibly independent of extension. At all values of t/aT for which the maximum extensibility is time-independent, the relaxation rate was also found to be independent of λ. These observations indicate that the monomeric friction coefficient is strain-independent over the ranges of T and λ covered in the present study. It was found that λm0=8.6 and that the largest extension ratio at break (λb)max is 7.3. Thus, rupture always occurs before the network is fully extended.

Anisotropy in Green Strength Induced During Elastomer Processing

1982 ◽  
Vol 10 (1) ◽  
pp. 3-15 ◽  
Author(s):  
G. R. Hamed ◽  
J. H. Song
Keyword(s):  
Natural Rubber ◽  
Molecular Level ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Rubber Blends ◽  
Green Strength ◽  
Styrene Butadiene

Abstract The tensile anisotropy induced while milling both gum and filled natural rubber, styrene-butadiene rubber, and natural rubber/styrene-butadiene rubber blends is investigated. The effects of annealing and the extent of milling on this phenomenon are presented. Molecular level explanations for this phenomenon are offered.

Styrene-Butadiene Rubber Filled with Fluorinated Carbon Black: Part II. Effect of Curative Level

1996 ◽  
Vol 69 (2) ◽  
pp. 273-276 ◽  
Author(s):  
K. Ames ◽  
D. Gibala ◽  
G. R. Hamed
Keyword(s):  
Carbon Black ◽  
Tensile Properties ◽  
The Other ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Conventional Furnace ◽  
Furnace Black ◽  
Fluorinated Carbon ◽  
The One ◽  
Styrene Butadiene

Abstract The cure and tensile properties of sulfur vulcanized styrene-butadiene rubber filled with a conventional furnace black or a fluorinated black have been determined. Compositions with the fluorinated black and normal curative levels exhibit retarded cure compared to corresponding ones with the furnace black. This is due to a reaction between the sulfenamide accelerator and the fluorinated black. Notwithstanding, a fluoro-filled composition with no curatives substantially crosslinks when molded at 150°C. Thus, fluoro-black filled specimens have competing effects toward crosslinking. On the one hand, crosslinking is inhibited by reaction with the accelerator, while, on the other hand, the fluoro-black itself can cause crosslinking.

scholarly journals Tailoring properties of polylactic acid/rubber/kenaf biocomposites: Effects of type of rubber and kenaf loading

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5679-5695
Author(s):  
Nur Fazreen Alias ◽  
Hanafi Ismail ◽  
Ku Marsilla Ku Ishak
Keyword(s):  
Mechanical Properties ◽  
Surface Morphology ◽  
Water Absorption ◽  
Polylactic Acid ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Green Strength ◽  
Internal Mixer ◽  
Styrene Butadiene ◽  
Fractured Surface

Polylactic acid (PLA) biocomposites were prepared by melt blending in an internal mixer with various types of rubber. The rubber was 90/10 wt% and was mixed before the addition of kenaf fiber (0 to 20 phr). Natural rubber (NR), nitrile butadiene rubber (NBR), and styrene butadiene rubber (SBR) were used. The effects of different types of rubber and kenaf loading were investigated based on processing torque, water absorption, mechanical properties, and fractured surface morphology. A similar trend in processing torque was observed throughout the composition of biocomposites. The stabilization torque was highest for the biocomposite with NR, followed by SBR and NBR. Water absorption increased as the kenaf loading increased. The polarity of NBR and SBR contributed to higher water absorption in the biocomposites compared to the NR. The strain-induced crystallization phenomenon and higher green strength of NR contributed to the highest tensile strength, elongation at break, and impact strength of the biocomposite compared to the NBR and SBR toughened PLA/kenaf biocomposite. More plastic deformation and less fiber pullout were observed in the fractured surface morphology. However, by increasing the kenaf loading, the mechanical properties decreased for all biocomposites, which was due to poor interfacial adhesion and agglomeration.

Styrene-Butadiene Rubber Filled with Fluorinated Carbon Black

1993 ◽  
Vol 66 (2) ◽  
pp. 286-294 ◽  
Author(s):  
J. Rodriguez ◽  
G. R. Hamed
Keyword(s):  
Surface Energy ◽  
Carbon Black ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Volume Percent ◽  
Conventional Furnace ◽  
Furnace Black ◽  
Fluorinated Carbon ◽  
Cure Rates ◽  
Styrene Butadiene

Abstract A comparison is made of the properties of an SBR 1502 containing twenty volume percent of conventional furnace black, or one of three fluorinated blacks. Fluorination slows the rate at which the filler incorporates and disperses into the rubber. Final mixing torque decreases as the degree of fluorination increases, apparently due to a reduction in surface energy of the filler. Compositions with fluorinated blacks have reduced scorch times and decreased cure rates relative to compositions with normal furnace black. This is attributed to acidity of the fluorinated blacks. Scorch time increases in a linear fashion with pH of the filler. Tensile strengths of samples containing fluorinated blacks are about seven times that of a gum composition, but about 30% less than vulcanizates with regular furnace black.

Relationship between the Cohesive Strength and Tack of Elastomers: Part IV, Carbon Black Filled Styrene-Butadiene Rubber

1995 ◽  
Vol 68 (2) ◽  
pp. 248-258 ◽  
Author(s):  
G. R. Hamed ◽  
P. S. Wu
Keyword(s):  
Elastic Response ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Surface Site ◽  
Chain Mobility ◽  
Test Speed ◽  
Response Change ◽  
Reduced Rate ◽  
Styrene Butadiene ◽  
Reduced Temperature

Abstract The autohesion and cohesion of uncrosslinked SBR (gum and black-filled) have been determined over a broad range of test temperatures and rates using a T-peel geometry. Peeling energies can be time-temperature superposed to form mastercurves using shift factors in accord with the WLF form. Universal constants are appropriate for the gum. While experimental constants were obtained for the black composition. Cohesion for the gum and filled SBR increase continuously with increasing test speed or reduced temperature. On the other hand, autohesion for the gum shows an abrupt transition by decreasing at a critical reduced rate, while autohesion of the filled SBR does not exhibit the transition. The transition is associated with a viscous-to-elastic response change with increasing RaT; filled SBR has reduced elasticity relative to the gum and hence the transition is not present. By examining relative autohesion, it is seen that the gum undergoes an interfacial-cohesive-interfacial transition response with increasing RaT. This is quite different than the behavior found when peeling apart elastomer/hard substrate bonds, such as the SBR/polyester bonds of Gent and Petrich; here, there is simply a cohesive-interfacial transition with increasing RaT. For elastomer-elastomer junctions there is interpenetration and chain mobility in the interphase formed. At sufficiently low RaT, interdiffused chains simply slide by one another giving interfacial failure. With increasing RaT entanglement couplings in the interphase become effective in preventing facile flow, and, at this point, failure becomes cohesive; finally, at even higher RaT, with a sufficiently elastic response, stresses apparently become concentrated at the interface and failure proceeds there. When an elastomer is bonded to a hard, immobile material, the mechanism of bonding is restricted to surface site adsorption. This reduces elastomeric chain mobility and produces more “glassy” dispersive interactions which resist separation relative to the chains which are held together by “rubbery” dispersive forces. Again at sufficiently high RaT, with increased elasticity, failure becomes interfacial.

DISCOVERY AND DEVELOPMENT OF A NEW SYNTHETIC RUBBER: HIGH TRANS SBR

2013 ◽  
Vol 86 (3) ◽  
pp. 343-350 ◽  
Author(s):  
Russell A. Livigni
Keyword(s):  
Organometallic Compound ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Green Strength ◽  
Repeat Units ◽  
Synthetic Rubber ◽  
Excellent Candidate ◽  
Styrene Content ◽  
Styrene Butadiene ◽  
Selection Of

ABSTRACT The discovery and development of high trans styrene–butadiene rubber (SBR) is presented. High trans SBR is prepared using a novel polymerization initiator of a specific combination of a barium salt and organometallic compound in a hydrocarbon solvent. The trans-1,4 content of the polybutadiene repeat units is sufficiently high, at a low vinyl content, to result in a crystallizing rubber. As a result, high trans SBR has high green strength similar to natural rubber (NR). The barium-based initiating system allows the formation of copolymers between butadiene and styrene, in which the distribution of styrene repeat units is considerably more random than that obtained with an organolithium initiator alone. By a judicious selection of the two initiator composition and the styrene content in the copolymer, high trans SBR also exhibits good building tack, again similar to NR. The properties of high green strength and good building tack for high trans SBR are unique among common synthetic rubbers. As such, high trans SBR is an excellent candidate for use as a tire carcass rubber in radial ply tire construction. High trans SBR is also valuable in tire tread compositions, providing good abrasion resistance.

Effects of White Rot Fungus Physisporinus sp., Isolated in Japan, on Styrene-butadiene Rubber

2020 ◽  
Vol 93 (9) ◽  
pp. 289-292
Author(s):  
Yumi SHIMIZU ◽  
Shuma SATHO ◽  
Taro NAKAJIMA ◽  
Hiroaki KOUZAI ◽  
Kiminori SHIMIZU
Keyword(s):  
White Rot ◽  
White Rot Fungus ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Styrene Butadiene
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