Unformatted text preview: Ea continuously decreased with increasing T-SiO 2 content, indicating that the treated silica facilitated the vulcanization of the fluoroelastomer. FC 2660 comprising 4% T-SiO 2 displayed the lowest activation energy (32.6 KJ/mol) among all the samples, which is in agreement with the results obtained from Haake mixing where FC 2660/ 4% T-SiO 2 exhibited the highest mixing torque. The promotion of the fluoroelastomer vulcanization by the T-SiO 2 is explained by its function as a secondary crosslinking agent. T-SiO 2 reduces the activation energy of neat FC 2660 from 81.0 kJ/mol to 65.1 and 32.6 kJ/mol for 2 and 4% T-SiO 2 , respectively (Table 2). In comparison, 2 and 4% untreated silica reduced the activation energy to 72.3 and 67.8 kJ/mol, respectively. The higher activation energy of the T-SiO 2 composites (especially at 4% nanofiller content) again proved the crosslinking effect of the silane coupling agent....
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- Spring '08