New Insight into Hierarchical Structures of Carbon Black Dispersed in Polymer Matrices:  A Combined Small-Angle Scattering Study

Abstract

Using a combined ultra-small-angle and small-angle scattering (CSAS) method of neutrons and X-rays, we investigated hierarchical structures of carbon black (CB) highly loaded in polyisoprene (PI) and poly-(styrene-random-butadiene) copolymer (SBR) under mechanical field (defined respectively as CB/PI and CB/ SBR) as well as in toluene under a sonic field (defined as CB/toluene). In order to analyze each structure level comprising the hierarchical structures of CB from the CSAS profiles, we employed the unified Guinier/powerlaw approach proposed by Beaucage (J. Appl. Cryst. 1995, 28, 717). Furthermore, in order to extract not only sizes but also shapes of the structure elements, we developed a modified approach, in which the Guinier scattering function utilized in the Beaucage approach was replaced by a form factor of the corresponding structure. Comparison of the scattering profiles from CB/PI and CB/SBR with CB/toluene clarified that (i) the smallest structure elements of CB (that further form mass-fractal objects) in PI and SBR were not an unbreakable unit of the CB filler which resulted after sonification in toluene but were instead composed of the several unbreakable units bounded together by polymer chains (defined as "dispersible units") and (ii) sizes and shapes of the dispersible units depended on the polymer matrix: Its size was larger in PI than in SBR. (iii) Moreover, the enlarged size of the dispersible unit in PI was found to enlarge the upper cutoff length of the mass-fractal structure in PI, while the mass-fractal dimensions themselves remained unchanged between PI and SBR. Hence, the detailed characterizations of the hierarchical structures by using CSAS shed new light on the dispersion process of the filler compound in the polymer matrix.

Nanocavitation in Carbon Black Filled Styrene–Butadiene Rubber under Tension Detected by Real Time Small Angle X-ray Scattering

“…Here the power law exponents are −3.67 and −3.65 in the x and y direction respectively, consistent with literature values. 53 At small λ before nanocavitation occurs (Figure 4b), the pattern in the low q region weakly splits along the tensile direction and tends to form a faint butterfly scattering pattern. The corresponding 1-D intensity in Figure 5, parts a and b (red lines), slightly decreases in the low q region in the y direction but increases in the x direction as was observed in the un-crosslinked specimen.…”

Not just fractal surfaces, but surface fractal aggregates: Derivation of the expression for the structure factor and its applications

“…1(b)). In such a case, this type of scaling is attributed to the properties of surfaces (regardless if these are surfaces of amorphous particles 23 or external crystal surfaces 24 ), excluding smaller particle morphologies.…”

Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering. I. Application to industrial multi-component nanocomposites

“…To improve wear and tear resistance, filler particles, such as carbon black (CB) and silica particles (SP), are mixed into the rubber matrix. The spatial distribution of filler particles in the rubber matrix determines not only the tyre's reinforcement but also its energy loss performance (Schaefer et al, 2000;Koga et al, 2005Koga et al, , 2008Takenaka et al, 2009;Bouty et al, 2014;Genix & Oberdisse, 2015). In accordance with the empirical knowledge that a homogeneous dispersion of filler particles lowers the energy loss, various attempts towards dispersion control have been conducted (Byers, 2002).…”