New Insights into the Morphology of Silica and Carbon Black Based on Their Different Dispersion Behavior

Abstract

Precipitated silica in combination with bifunctional organosilanes almost fully replaces currently the commonly used carbon black fillers in modern passenger car tire tread compounds to improve tire properties such as wet traction (safety) and rolling resistance (fuel consumption). However, it is still challenging to reach a sufficient level of abrasion resistance (service life). An optimum macrodispersion quality of the silica is a fundamental precondition for an optimum abrasion resistance. This goal can be reached by the development of new tailor-made highly dispersible silica grades. In order to achieve this, it is essential to be aware of the analytical silica parameters, which affect the dispersion process. One of these parameters known from carbon black is the structure of the filler. To gain deeper insights into the in-rubber dispersibility of the silica, the structure was investigated by two different methods, the DOA measurement and the void volume measurement. The results were correlated to the in-rubber macrodispersion. In contrast to carbon black filled compounds, no sufficient correlation of the structure with the macrodispersion could be found for the silica-filled compounds. Therefore, it was concluded that the morphology of silica differs from that one that is claimed for carbon black. Additional investigations like TEM, FT-IR and X-ray diffraction measurements were carried out. Carbon black shows a more elastic structure, which can withstand the external forces during the mixing process in a better way. Silica contains a much higher void volume in the structure even after exposed to high forces. These new findings will help to understand the macrodispersion process in rubber in a better way.

Highly enhanced tire performance achieved by using combined carbon nanotubes and soybean oil

“…Figure 2 shows TEM images before and after milling of the RS‐CNTs master batch, as well as an image of the high‐loading silica‐based elastomer composite with carbon nanotubes. It is well known that the improved dispersion of reinforcing fillers may ensure a low hysteresis loss and favorable rolling resistance of the fabricated elastomer composite 26,27 . Therefore, in this study, the dispersion of carbon nanotubes with strong interactions via van der Waals forces is important to ensure the good rolling resistance of the high‐loading silica‐based elastomer composite.…”

“…loss and favorable rolling resistance of the fabricated elastomer composite. 26,27 Therefore, in this study, the dispersion of carbon nanotubes with strong interactions via van der Waals forces is important to ensure the good rolling resistance of the high-loading silica-based elastomer composite.…”

Influence of compounding and mixing on filler dispersion and curing behavior of silica compounds

“…[77] Not only the mixing conditions, but also the silica itself strongly influence the degree of dispersion in a rubber matrix. [77,78] Measuring laser diffraction of a silica suspension after ultrasonic treatment can be an indication of silica dispersibility. [77,78] When a sufficient amount of energy is applied to a silica suspension by ultrasonic treatment, clusters are destroyed to the initial structure.…”

“…[77,78] Measuring laser diffraction of a silica suspension after ultrasonic treatment can be an indication of silica dispersibility. [77,78] When a sufficient amount of energy is applied to a silica suspension by ultrasonic treatment, clusters are destroyed to the initial structure. [63,68] The results of this measurement for HD silica and conventional silica [63,68] are shown in Figure 2.18.…”

“…Many studies were done and are still ongoing for novel material development such as polymer functionalization and optimizing the dispersibility of silica in order to overcome these problems. [77,78,[83][84][85] But still, using silane coupling agents is the best way to solve the problems. The silane coupling agent strongly affects the filler-filler and filler-polymer interaction, thus mechanical properties and processability of silica filled rubber can be enhanced.…”