Structure and Density of Crosslinks in Natural-Rubber Vulcanizates. A Combined Analysis by NMR Spectroscopy, Mechanical Measurements, and Rubber-Elastic Theory

Gronski, W.; Hoffmann, Uwe; Simon, Géza; Wutzler, A.; Straube, E.

doi:10.5254/1.3538608

Cited by 90 publications

(71 citation statements)

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“…Dipolar couplings in solids can be measured by their effects on spin-spin relaxation times via second moment analysis [31], double quantum methods [32 -35], or echo decay methods [29,36]. In cases where the correlation time for the residual dipolar couplings remains fairly unchanged, the decay of transverse magnetization in a spin-echo experiment simplifies to…”

Section: Experimental Methodsmentioning

confidence: 99%

Molecular dynamics studies on the effects of water speciation on interfacial structure and dynamics in silica-filled PDMS composites

Gee

Maxwell

Balazs

2004

Polymer

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The effect of chemisorbed and physisorbed water on the interfacial structure and dynamics in silica-filled polydimethylsiloxane (PDMS) based composites have been investigated. Toward this end, we have combined molecular dynamics simulations and experimental studies employing dynamic mechanical analysis and nuclear magnetic resonance analysis. Our results suggest that the polymer-silica contact distance and the mobility of interfacial polymer chains significantly decreased as the hydration level at the interface was reduced. The reduced mobility of the PDMS chains in the interfacial domain reduced the overall, bulk, motional properties of the polymer, thus causing an effective 'stiffening' of the polymer matrix. The role of the long-ranged Coulombic interactions on the structural features and chain dynamics of the polymer were also examined. Both are found to be strongly influenced by the electrostatic interactions as identified by the bond orientation time correlation function, local density distribution and radial distribution functions. These results have important implications for the design and life performance behavior of nanocomposite silica -siloxane materials. q

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Section: Experimental Methodsmentioning

confidence: 99%

Molecular dynamics studies on the effects of water speciation on interfacial structure and dynamics in silica-filled PDMS composites

Gee

Maxwell

Balazs

2004

Polymer

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“…The method has been described in full detail in references. [14][15][16][17][18] The physical crosslink density is understood as the long chain entanglements and interaction between CB surface and rubber molecules. Uncured compounds were placed into the testing machine, the decay signal was analyzed and the result was taken as the physical crosslink density.…”

Section: Measurement Of Crosslink Densitymentioning

confidence: 99%

Influence of Carbon Black on Crosslink Density of Natural Rubber

Zhao

Chen

Pan

et al. 2012

Journal of Macromolecular Science, Part B

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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.

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“…Nuclear magnetic resonance methods have shown significant ability to quantify chemical and network changes occurring during siloxane elastomer degradation [6][7][8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Chemical origins of permanent set in a peroxide cured filled silicone elastomer – tensile and 1H NMR analysis

Chinn

DeTeresa

Sawvel

et al. 2006

Polymer Degradation and Stability

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Structure and Density of Crosslinks in Natural-Rubber Vulcanizates. A Combined Analysis by NMR Spectroscopy, Mechanical Measurements, and Rubber-Elastic Theory

Cited by 90 publications

References 0 publications

Molecular dynamics studies on the effects of water speciation on interfacial structure and dynamics in silica-filled PDMS composites

Molecular dynamics studies on the effects of water speciation on interfacial structure and dynamics in silica-filled PDMS composites

Influence of Carbon Black on Crosslink Density of Natural Rubber

Chemical origins of permanent set in a peroxide cured filled silicone elastomer – tensile and 1H NMR analysis

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