Silica-filled vulcanized

Effect of Pre-Stressing on Young s Modulus of Silica-Filled Vulcanized NR... 

Figure 3.10 Stress-strain plot of pre-stressed silica-filled vulcanized NR containing 3 pphr of silane coupling agent (reproduced from reference 44).

Volume fraction of rubber in swollen gel, (v,) vs pre stress level of silica-filled vulcanized NR... 

Figure 3.14 Effect of cyclic pre-stressing (10 cycles at 10 MPa) on volume fraction of rubber in the swollen gel of silica-filled vulcanized NR containing different amounts of coupling agent, Si69.

Tearing energy of silica-filled vulcanized rubber vs rate at 23 C (5 pphr 5169)... 

S. Wolff, Reinforcing and vulcanization effects of silane Si-69 in silica-filled compounds, Kautsch. Gummi, Kunstst., 34, 280-284, 1981. 

Diamine salts of fatty acids are used as multifunctional additives in natural rubber compounds filled with carbon black.They affect the elastomer-carbon black interface. With an increased concentration of multifunctional additive, the concentration of bound rubber decreases but dispersion of carbon black is improved. In silica filled rubber, multifunctional additive also improves the dispersion of silica, but in addition, it decreases the negative influence of silica filler on vulcanization rate. 

Tensile strength vs silane coupling agent Si69 of vulcanized silica-filled NR... 

S.M. Hosseini, M. Razzaghi-Kashani, Vulcanization kinetics of nano-silica filled styrene butadiene rubber. Polymer, ISSN 0032-3861 55 (24) (November 18, 2014) 6426-6434. http //dx.doi.0rg/lO.lOl6/j.polymer.2Oi4.O9.O73. 

Silicone rubber and, in general polar polymers, are by nature materials of choice for preparing silica filled systems however limited to niche applications, with respect to the range of properties that such specialty polymers may offer. In order to develop optimum reinforcing performance with more common diene elastomers, silica must be chemically treated as we will see below, because contrary to carbon blacks, silica particles do not develop spontaneous strong interactions with nonpolar polymers. It is nevertheless interesting to see that, even with comparable size and structure, pure silica does not affect the mechanical properties of vulcanized rubber compounds in the same manner as carbon black. 

Organofunctional polysiloxanes with silanol groups can be cross-linked at low temperatures with tetrabutyl titanium, methyl triacetoxy-silane, and similar compounds and are thus used as cold vulcanization materials. In contrast, hot vulcanizable silicones possess one vinyl group in about 500-1000 monomeric units and can be cross-linked with peroxides. All silicon rubbers are filled with highly dispersed silica since the unfilled rubber is practically a useless elastomer. 

Cure time corresponds to the time required for optimum vulcanization of samples. NR filled with different silica types (precipitated silica, PSi and fumed silica, FSi) have been prepared and their cure characteristics features were analyzed. The corresponding data related to the cure characteristics, scorch time (ts2), cure time (tc9o) cure rate index (CRI) and minimum torque (Ml) are recorded in Table 18.10. It can be seen that compared to PSi/NR compounds, degree of reversion and viscosity are higher for FSi/NR compounds at the same... 

Other interesting kind of nanoparticle are silice, Li et al. studied the properties of vulcanized mbber nanocomposite filled with nanokaolin and precipitated silica, demonstrating that the presence of nanokaolin improve the thermal stability, this due to the good interfacial interaction between the nanokaoUn and the chains of mbber in the nanocomposite [90]. 

Liu, Q., Zhang, Y., Xu, H. Properties of vulcanized robber nanocomposite filled with nanokaolin and precipitated silica. Appl. Clay Sci. 42, 232-237 (2008)... 

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