The Effect of Silanization Temperature and Time on the Marching Modulus of Silica-Filled Tire Tread Compounds

Abstract

Marching modulus phenomena are often observed in silica-reinforced solution styrene–butadiene rubber/butadiene rubber (S-SBR/BR) tire tread compounds. When such a situation happens, it is difficult to determine the optimum curing time, and as a consequence the physical properties of the rubber vulcanizates may vary. Previous studies have demonstrated that the curing behavior of silica compounds is related to the degree of silanization. For the present work, the effect of silanization temperature and time on the marching modulus of silica-filled rubber was evaluated. The correlations between these mixing parameters and their effect on the factors that have a strong relation with marching modulus intensity (MMI) were investigated: the amount of bound rubber, the filler flocculation rate (FFR), and the filler–polymer coupling rate (CR). The MMI was monitored by measuring the vulcanization rheograms using a rubber process analyzer (RPA) at small (approximately 7%) and large (approximately 42%) strain in order to discriminate the effects of filler–filler and filler–polymer interactions on the marching modulus of silica-filled rubber compounds. The results were interpreted via the correlation between these factors and their effect on the MMI. A higher temperature and a longer silanization time led to a better degree of silanization, in order of decreasing influence.

Comparison between SBR Compounds Filled with In-Situ and Ex-Situ Silanized Silica

“…The Payne effect can be used to study the filler status, that is, the micro-dispersion of the filler in the rubber. Therefore, a better micro-dispersion of the filler in the matrix would lead to a lower Payne effect [ 7 ]. Observing Figure 10 b, it can be concluded that the dispersion of the silica has an enormous effect on the mechanical properties of the rubber compounds.…”

“…During this procedure two chemical reactions take place: (i) bonding of the organosilane to the silica surface and (ii) reaction between the silane and the rubber. This mixing method exhibits some disadvantages, such as the need for an additional step to ensure the finalization of the reaction between the silane and the silica and the generation of ethanol as a by-product of the silanization reaction [ 6 , 7 , 8 ]. The first one leads to longer mixing times, the second contains the risk of porosity at the surface of the extrudate.…”

Effect of conductive carbon black on electrical conductivity and performance of tire tread compounds filled with carbon black/silica hybrid filler

“…Many attempts have therefore been made to investigate the parameters influencing the tire performance, especially FSE and WG, for example, rubbers, [2][3][4][5] activators, 6,7 fillers, [8][9][10] silane coupling agents, 11,12 processing oils, [13][14][15] and mixing conditions. 16,17 Focusing on fillers, the balanced tire performance is usually gained in the system containing carbon black/silica (CB/SiO 2 ) hybrid filler. Veiga et al reported that the partial replacement of CB by SiO 2 (15 phr at the replacing ratio of 1:1) with the presence of bis [3-(triethoxysilyl)propyl]tetrasulfide (3 phr) can improve abrasion resistance (~4%), rolling resistance (~10%) and WG (~19%) of the tread vulcanizates.…”

Synergistic Effect by Polyethylene Glycol as Interfacial Modifier in Silane-Modified Silica-Reinforced Composites

“…As a consequence, the silica surface has to be silanized in order to make it hydrophobic [ 5 , 6 ]. The sulfur containing silane coupling agents, such as bis(3-(triethoxysilyl)-propyl) tetrasulfide (TESPT) and bis (3-(triethoxysilyl)-propyl) disulfide (TESPD), are commonly used, which have a potential to create sulfur linkages between silica surface and the unsaturated polymer matrix and greatly improve the polymer–filler interaction [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. Compared to the TESPT, TESPD has a higher temperature stability and, therefore, improved scorch during silanization when high mixing temperatures are required.…”