Silica-filled rubbers rubber-filler interaction

The higher amounts of bound rubber for all samples filled with plasma-treated silica demonstrate an improved filler-polymer interaction between the plasma-treated silica and the polymers in the blend compared to untreated and silane-treated silica. The highest filler-polymer interaction for the PPy-silica can be due to the best compatibilization effect of PPy-silica with both polymers in the blend, as... 

A low-resolution proton NMR method is one of the few techniques that have so far proved to be suitable for studying elastomer-filler interactions in carbon-black-filled conventional rubbers and silica-filled silicon rubbers [20, 62, 79]. It was pointed out by McBrierty and Kenny that Many of the basic characteristics of filled elastomers are revealed by low resolution spectra while the more sophisticated techniques and site specific information refine interpretations and clarify motional dynamics [79]. 

The characterization of the elastomer-filler interactions at a molecular level may be cairied out by spectroscopic techniques such as IR and NMR spectroscopy. X-ray and neutron scattering, dynamic mechanical and dielectric spectroscopy, and molecular dynamics simulations [6]. Up to now, the most comprehensive studies of silica filled PDMS [4, 7-22] and carbon black filled conventional rubbers [23] have been carried out by H [4, 7—20, 23], [21], and C NMR relaxation experiments [22],... 

Figure 15.33 shows benzene uptake by natural rubber samples. Filled samples absorb less solvent (lower swelling). The carbon black containing sample had a lower benzene uptake than the silica filled sample. The lower swelling of the carbon black containing sample is due to high bound rubber content, the crosslink density of the black filled vulcanizate, and a strong rubber-filler interaction. 

Zhang, W. and Leonov, A. I. 2001. IGC study of filler-filler and filler-rubber interactions in silica-filled compounds. Journal of Applied Polymer Science 81 2517-2530. 

Ito et al. examined the ESR spectra of surface modified silica filled SBR unvulcanizates to get information on the filler/rubber interactions. The ESR spectra of vinyl trimethoxy silane (VS) modified silica filled SBR unvulcanizates (U-VS) and (bis(triethoxysilyl propyl)-tetrasulfide (TESPT) modified silica filled SBR unvulcanizates (U-TESPT) measured at —100 °C and at dilferent initial strains are shown in Figure 25.28(a) and (b), respectively. It is found that the intensity of signals increases with increasing initial strain without changes in... 

Micron-sized fillers, such as glass fibers, carbonfibers, carbon black, talc, and micronsized silica particles have been considered as conventional fillers. Polymer composites filled with conventional fillers have been widely investigated by both academic and industrial researchers. A wide spectrum of archival reports is available on how these fillers impact the properties. As expected, various fundamental issues of interest to nanocomposites research, such as the state of filler dispersion, filler-matrix interactions, and processing methods, have already been widely analyzed and documented in the context of conventional composites, especially those of carbon black and silica-filled rubber compounds [16], It is worth mentioning that carbon black (CB) could not be considered as a nanofiller. There appears to be a general tendency in contemporary literature to designate CB as a nanofiller - apparently derived from... 

Two major fillers used in the rubber industry are silica and carbon black. Carbon black is black because it absorbs/scatters all radiation, including infrared, impinging on it. Hence, simple transmission spectroscopy of carbon black filled specimens is not straightforward and is usually not possible unless the samples are very thin. Carbon black filled samples have not been readily examinable using micro-spectroscopic methods. Silica filled systems are more amenable to microscopic techniques [76] and can be examined to determine silica-polymer(rubber) interactions. The presence of inorganic materials, e.g., transition metal complexes in... 

Having the interaction site well identified in a filled polymer system, in terms of chemical activity and surface, and a clear picture of the nature of the polymer-filler interaction allow quite convincing theoretical models to be developed. Such a favorable situation is however restricted to a few cases, namely silica/polysiloxane systems. With other systems, either the nature of the polymer-filler interaction is badly known or the size of the interaction site cannot be clearly quantified, or both. In such case however, the successful silica/PDMS case provides some interesting guidelines when assuming that, whatever are the respective chemical natures of the filler and the polymer, at least the physics is the same. As we have seen the author has successfully adapted this model to the case of carbon black/rubber systems, with however the additional difficulty that the surface area of the interaction site Aq cannot be known a priori (see Chapter 5, Section 5.1.5). 

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