Influence of Carbon Black on Crosslink Density of Natural Rubber

Abstract

Vulcanization and reinforcement are two important factors contributing to the properties of vulcanized rubber. In order to investigate the influence of carbon black (CB) on chemical crosslinking, three groups of samples with different crosslink densities were prepared. In each group with the same crosslink density, different amounts of CB were introduced. Data fitting showed that delta torque ( M = M H -M L , the difference between the highest and lowest torques during curing) in the cure curves of each group had a good linear relationship with CB load and extrapolation of the fitting lines almost intercepted the x coordinate at the same value, which indicated that CB had no influence on the chemical crosslinking of the rubber. To verify the above result, a series of nonfilled natural rubber (NR) vulcanizates with different crosslink densities were studied using equilibrium swelling and the swelling ratios were compared with those of corresponding CB filled rubbers with the same sulfur and accelerator amount. The results of both the equilibrium swelling and NMR relaxation parameter measurements showed that CB filled vulcanizates had higher apparent crosslink densities than those of unfilled ones due to the strong interaction between rubber molecules and the surface of the CB particles. The swelling ratios of filled rubbers had a parallel relationship with those of the unfilled ones which indicated that CB had little influence on chemical crosslink density introduced by chemical vulcanization.

The effect of interface morphology in waste tyre rubber powder filled elastomeric matrices on the tear and abrasion resistance

“…The possible reason may be attributed to smaller particles of MRP074 which provide slightly more reinforcement compared to CRP400. As expected, in carbon black filled compound, the addition of carbon black increases ΔM through physical absorption and/or chemical bonding between rubber molecules and CB surfaces [22]. The ΔM reduction is more obvious in carbon-filled than unfilled NR or NR/BR compound.…”

Influence of kaolinite particle size on cross-link density, microstructure and mechanical properties of latex blending styrene butadiene rubber composites

“…When filler is incorporated into rubber, along with cross linking agents, a complex network [2] is formed. It comprises a network introduced by chem ical cross linking, a network formed through the physical interaction between filler aggregates and a network formed between filler particles and rubber molecules through physical adsorption or chemical bonds, which is also called a bound rubber layer.…”

“…As applied to an amorphous elastomer such as styrene butadiene rubber (SBR), the vulca nization process yields resilient products having elastic properties but very little strength. Strength properties are introduced by the addition of "rein forcing" fillers, with carbon black being by far the most commonly used [2].…”

“…Until now, there are only few methods avail able for the determination of crosslink density. For conventional elastomers, equilibrium swelling mea surements [6][7][8], mechanical tensile tests in combi nation with Mooney Rivlin plots [9] and magnetic resonance techniques (NMR) [10,2,5] are used for this purpose. In this study, the traditional equilibrium swelling method was used to investigate the influence of kaolinite with different particle size on cross link density, microstructure and mechanical properties of styrene butadiene rubber (SBR).…”

Determination of vulcanization rate constant, crosslink density, and free sulfur content on carbon black flled EPDM

“…Strong bonds are formed between rubber molecules and the surface of carbon black particles (Hartwell, 2003). Carbon black filled with rubber vulcanization has a strong Materials EV SEV CV EV1 EV2 EV3 SEV1 SEV2 SEV3 CV1 CV2 CV3 phr phr phr phr phr phr phr phr phr EPDM 100 100 100 100 100 100 100 100 100 CB N220 50 60 70 50 60 70 50 60 interaction between rubber molecules and the surface of filler particles (Fei et al, 2012).…”