Mechanism of aggregate formation in simplified industrial silica styrene–butadiene nanocomposites: effect of chain mass and grafting on rheology and structure

Abstract

The formation of aggregates in simplified industrial styrene-butadiene nanocomposites with silica filler has been studied using a recent model based on a combination of electron microscopy, computer simulations, and small-angle X-ray scattering. The influence of the chain mass (40 to 280 kg mol(-1), PI < 1.1), which sets the linear rheology of the samples, was investigated for a low (9.5 vol%) and high (19 vol%) silica volume fraction. 50% of the chains bear a single graftable end-group, and it is shown that the (chain-mass dependent) grafting density is the structure-determining parameter. A model unifying all available data on this system is proposed and used to determine a critical aggregate grafting density. The latter is found to be closely related to the mushroom-to-brush transition of the grafted layer. To our best knowledge, this is the first comprehensive evidence for the control of the complex nanoparticle aggregate structure in nanocomposites of industrial relevance by the physical parameters of the grafted layer.

Biologically sustainable rubber resin and rubber‐filler promoter: a precursor study

“…In this case, the slope of a log I , intensity versus log q plot is 3 to 4 for a rough surface . The interfacial roughness can be correlated to the interaction of silica with a polymer chain . In order to investigate the HDS flocculation phenomenon, the radius of gyration R g for HDS was estimated according to eqn .…”

“…[31] The interfacial roughness can be correlated to the interaction of silica with a polymer chain. [45] In order to investigate the HDS flocculation phenomenon, the radius of gyration R g for HDS was estimated according to eqn 7. Based on the premise that the shape of aggregates is spherical with radius R a , the radius of gyration R g can be described in relation to R a as follows:…”

Structure and linear viscoelasticity of polymer nanocomposites with agglomerated particles

“…Attractive interaction between particles is very common in polymer nanocomposites, which may result in agglomeration of particles, and the smaller the particle size, the more evident the agglomeration. Actually, agglomeration has been observed in various systems, including nanosilica in styrenebutadiene rubber [6,7], polystyrene [8,9], polypropylene [10], poly(methyl methacrylate) [11], poly(ethylene oxide) [12,13], polyolefin elastomer [14e16], and carbon black in polyethylene [17,18], polypropylene [19,20], polystyrene [21], poly(methyl methacrylate) [22,23]. The agglomeration of NPs is not limited for the spherical shape, and it is also observed for fibrous particles [24e26].…”

A high-temperature dielectric process as a probe of large-scale silica filler structure in simplified industrial nanocomposites

“…8 The grafting density was identified as the key parameter by evidencing the existence of twin samples having a different composition but identical structure and elastic plateau moduli. 9 By combining small-angle scattering, electron microscopy, and numerical simulations, we have described the structure of such complex systems by primary silica beads organized within small aggregates, which themselves fill large-scale fractal branches.…”