Effects of surface chemistry of silica particles on secondary structure and tensile properties of silica‐filled rubber systems

Abstract

Silica particles were treated by silane coupling agents to study the effects of surface chemistry of silica particles on the secondary structure formed by silica particles in styrene-butadiene rubber (SBR). The relation between the size of secondary structure and tensile properties of silica-filled SBR vulcanizates was also investigated. The water molecules adsorbed on the silica surface enhanced both the reactivity of the coupling agents with silanol groups on the silica surface and the condensation reaction between coupling agents. The averaged size of one agglomerate in the filled vulcanizate (S agg ) decreased with the increase of the hydrophobic character of silica particles, which were obtained by the introduction of coupling agents with alkyl groups. The initial slope of stress-strain curves for silicafilled vulcanizates decreased with the decrease of S agg . Further, a clear Payne effect was observed in all silica-filled vulcanizates, with this tendency more prominent in the larger S agg .

Effects of rubber/filler interactions on deformation behavior of silica filled SBR systems

“…The moisture content of dried silica was about 2.0 wt% which was determined by thermal gravimetric analyzer. We confirmed that the moisture content of 2.0 wt% was enough to react the coupling agent with silanol groups [24].…”

“…It is well known that the stress-strain curves for silica filled rubber systems are affected by the crosslink density of rubber matrix [22,25], the size of agglomerates formed by the silica [24,26] and rubber/silica interactions [4,22]. These effects can be controlled by the contents of curing agents, the number of silanol groups on silica particles and the introduction of coupling agent.…”

“…The chemical structures of them are listed in Table 1. The reactivity of coupling agents with silanol groups on silica particles depends on the moisture content of silica particles [21,24]. In this study, as-received silica was dried at 120 8C under a reduced pressure for 12 h to control the moisture content.…”

Chain Scissions of Rubber Molecules by a Tensile Force in Filled Rubber Systems

“…The chemical structures of them are listed in Table 2. The reactivity of coupling agents with silanol groups on silica particles depends on the moisture content of silica particles 14,15) . Thus, as-received silica was dried at 120°C under a reduced pressure for 12 h to minimize the moisture content of silica particles.…”

Application of Acrylonitrile Butadiene Rubber for Management of Industrial Waste Silica

“…The explanation is given as the adsorption of zinc complex on the silica surface, thus lowering the sulfur vulcanization efficiency. (Table 3) Stress strain of rubber composite (Figure 2) (Table 4): It is well known that the stress-strain curves for silica filled rubber systems are affected by the crosslink density of rubber matrix [60,61], the size of agglomerates formed by the silica [62,63] and rubber / silica interactions [64,60]. These effects can be controlled by the contents of curing agents, the number of silanol groups on silica particles and the introduction of coupling agent.…”