Structure development in silica-filled polyacrylate rubber composites during mixing

Abstract

ABSTRACT:The structure of bound rubber in the composites from fumed silica (A200, Nippon Aerosil Co., Japan) and polyethylacrylate rubber (PEA) was studied as a function of mixing temperature. The fraction of bound rubber in the composites increased gradually with increasing the mixing temperature from 80 to 120°C, followed by saturation above 120°C. High-resolution solid-state NMR results revealed that there was no chemical bonding between silanol groups and PEA molecules. Scanning electron microscope and optical microscope observation of the composites indicated that, with increasing mixing temperature, the size of agglomerates formed by silica particles decreased. Further, the molecular weight retention of PEA dropped abruptly above 120°C. Dynamic viscoelastic measurements of the composites suggest that the development of network structure in the composites was greatly affected by the mixing temperature. Based on these data, structure development in composites is discussed.

Effects of rubber/filler interactions on the structural development and mechanical properties of NBR/silica composites

“…From these results, it is clear that the agglomeration of silica particles is suppressed by the existence of the nitrile group; in other words, the dispersity of silica particles was improved by the nitrile groups, in accordance with the report by Choi 29. The agglomerate is formed by the hydrogen bonding between silanol groups on silica surfaces 16–20. However, the agglomeration is suppressed by the nitrile groups of NBR because silanol groups form hydrogen bondings with nitrile groups.…”

“…We studied the effects of rubber/silica interactions on the formation of bound rubber. High‐resolution solid‐state NMR results for polyisoprene (PIR) and polyacrylate rubber (ACM)/silica showed no evidence for direct chemical coupling between silanol groups on a silica surface and rubber molecules 16, 17. Further, transmission electron microscopy (TEM) observations suggested that the bound rubber might correspond to the rubber component entrapped within the secondary structure formed by silica particles (agglomerates) 18–20…”

Silica Transfer in Ternary Rubber Blends: Calculation and Experimental Determination

“…According to the work of Kralevich and Koening49 van der Waals forces are responsible for the formation of the bound rubber in a nonpolar NR. Ono et al50, 51 also found no evidence for direct coupling between silanol groups and NR molecules at low processing temperature. Choi et al52 examined the SBR/silica interactions by microstructure analysis and revealed that the bound rubber is mainly formed by physisorption of the 1,2‐component of the butadiene units to the silica surface.…”

Preparation of scratch and abrasion resistant polymeric nanocomposites by monomer grafting onto nanoparticles, 2 Characterization of radiation-cured polymeric nanocomposites

“…On the other hand, the ratio Q 2 /Q 4 and Q 3 /Q 4 were not affected by the elimination of adsorbed water on the silica surface. [10] In addition, solvent extractions of samples were carried out to prove the formation of covalent bonds between organic and inorganic phases. In case of surface bonding DYNASYLAN MEMO cannot be removed by extraction with tetrahydrofuran (THF).…”