Characterization of Carbon Filler Distribution Ratio in Polyisoprene/Polybutadiene Rubber Blends by High-Resolution Solid-State ¹³C NMR

Abstract

The distribution ratio of carbon black (CB) in a blend of polyisoprene rubber (IR) and polybutadiene rubber (BR) is characterized using high-resolution solid-state 13C NMR. The relationships between the line width of the polymer's resonance lines and CB contents are estimated for both the IR/CB and BR/CB composites from the dipolar decoupling/magic angle spinning (DD/MAS) 13C NMR spectra. For the IR/CB composite, the IR line width increases with the increasing CB content. A similar relationship is obtained between the BR line width and CB contents for the BR/CB composite. These relationships are used as calibration curves. On the basis of these calibration curves, the distribution ratio of CB in the IR/BR rubber blend is determined. It is found for the IR/BR/CB composite that the amount of CB in the BR phase is approximately twice as high as that of CB in the IR phase, irrespective of the CB content. The sum of the amounts of CB in both the IR and BR phases, determined from the above 13C NMR experiments, mostly agree with the amount of CB originally added to the compound. This verifies the validity of the CB distribution determination method by 13C NMR, as proposed in this study. A comparison with a CB-gel method, which can only be used for unvulcanized rubber blends, further confirms the results obtained from the 13C NMR.

Silica Transfer in Ternary Rubber Blends: Calculation and Experimental Determination

“…It is obvious that the phase selective filler localization could not be characterized in both images. That is the main reason for developing indirect methods for the quantification of filler localization in highly filled binary blends19–25, 35–37 and ternary blends 38…”

“…Microscopy methods like transmission electron microscopy (TEM)7, 14 and atomic force microscopy (AFM)15–18 have been used for low‐filled blends. Electrical resistivity measurements,8–10 NMR,19, 20 differential scanning calorimetry (DSC),6, 12 and thermogravimetric analysis (TGA)21, 22 as well as dynamic mechanical analysis (DMA)23–25 have been used for highly filled blends. Particularly, using ternary polymer blends synergistic properties could be obtained, which have not been reached by binary blends.…”

Carbon black distribution driven by its concentration and its effect on physico‐mechanical properties of styrene butadiene rubber and butadiene rubber miscible rubber blends

“…The dispersion and distribution of fillers in RRB's become important as it affects the physical and mechanical properties of rubber products 21–25 . Dispersion and distribution of fillers in RRB's are studied using TEM, Atomic Force Microscopy (AFM), DMA, and SS‐NMR spectroscopy, respectively 20,26–31 . In our previous research work, we used TEM to study dispersion characteristics of CB, and quantified the amount of CB in the BR phase within immiscible NR/BR RRB's using DMA, attempts to correlate DMA data on partitioning of CB with SS‐NMR spectra were successful; mechanical properties of NR/BR RRB's were in good agreement with DMA data on partitioning of CB 31,32 .…”

Thermal stability of γ-irradiated chlorinated isobutylene–isoprene copolymer/chlorosulphonated polyethylene rubber blend/carbon black nanocomposites

“…This fact may emphasize the importance of the homogeneity of the mixes, where the increasing amount of undispersed CB pellet fragments and the agglomerates leads to a decrease in tensile properties of the cross-linked elastomeric nanocomposites. 9,10 Kotani et al 11 studied the CB distribution ratio in polyisoprene/polybutadiene rubber blends by high-resolution solid-state 13 C NMR.…”