Effects of modified silica on the co‐vulcanization kinetics and mechanical performances of natural rubber/styrene–butadiene rubber blends

Abstract

Rubber blends are widely used for combining the advantages of each rubber component. However, to date, how to determine and distinguish the vulcanization kinetics for each single rubber phase in rubber blends during the co‐vulcanization process is still a challenge. Herein, high‐resolution pyrolysis gas chromatography–mass spectrometry (HR PyGC‐MS) was employed for the first time to investigate the vulcanization kinetics of natural rubber (NR) and styrene–butadiene rubber (SBR) in NR/SBR blends filled with modified silica (SiO2). The reaction rates of crosslinking of each rubber phase in NR/SBR were calculated, which showed that the crosslinking rates of NR were much lower than those of SBR phase in the unfilled blends and blends filled with unmodified and silane modified silica. Interestingly, the vulcanization rates of NR and SBR phase were approximately same in the vulcanization accelerator modified silica filled blends, showing better co‐vulcanization. In addition, the vulcanization accelerator modified silica was uniformly dispersed and endowed rubber blends with higher mechanical strength compared to the untreated silica. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48838.

NMR Studies on the Phase-Resolved Evolution of Cross-Link Densities in Thermo-Oxidatively Aged Elastomer Blends

“…A rather shorter t 90 curing time of 8 min than the weighted average suggests that SBR has a shorter scorch time in the blend. As was reported recently, 41 this can be attributed to a higher reaction rate of SBR than that of NR in the blend, possibly due to π−π interactions between the aromatic rings of CBS accelerator and styrene in SBR rendering a preferential distribution of CBS in the SBR phase. A similar behavior in t 90 cures times of 15 and 5 min was obtained for two more variants of the blend, 10:90 and 90:10 (by phr), respectively, of NR/SBR, thus emphasizing the enhanced reaction rate of SBR in the blends.…”

Dynamic mechanical properties in natural rubber/styrene‐butadiene rubber blends: The local strain behavior in the glass transition region

“…The effect of the vulcanization rates on each NR and SBR phase in NR/SBR blends was recently analyzed in literature. [22] In this article, we analyze the influence of phase morphology of NR/SBR blends on the dynamic moduli in the glass transition region by means of a phase network model following the ideas of Klüppel et al [23,24] We will go deeper in the analysis of the local strain behavior of each phase taking into account the blend ratio and the vulcanization temperature. To this aim, a semi-EV system was formulated and two different vulcanization temperatures were chosen (160 C and 170 C) since these temperatures are normally used in technological applications.…”

Quantitative analysis of s-PB/SBR blend dispersion morphology using computer image processing-assisted Raman spectroscopic techniques

“…1 A finely dispersed rubber phase in rubber blends is critical to obtaining good mechanical properties. 2 As an essential parameter of blend morphology, homogeneity is conventionally used to evaluate the dispersion of rubber blends, affecting the mechanical properties of rubber blends to a large extent. 3 In order to study and observe the morphology and microstructure of polymer materials, microscopy techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) are frequently employed to obtain images providing detailed information for research.…”