Effect of Cyclic Deformations on the Dynamic‐Mechanical Properties of Silica‐Filled Butyl Rubber

The effect of the chemical modification of the silica surface by the silane coupling agent (Si69) on both the real and the imaginary parts of the shear compliance ( J′ , J″ ) on silica‐filled butyl rubber vulcanizates was investigated in a wide temperature and frequency range, −70 to 120 °C and 10 −4 to 10 Hz, respectively. In addition, the stress‐strain measurements, DSC, and TEM were carried out. Moreover the effect of stress‐strain cyclic deformation up to ten times with maximum deformation 80% of the elongation at break on J′ , J″ is also studied. It was found that the filler network recovers after cyclic stress‐strain in a time scale of one year at room temperature.Transmission electron photographs of the butyl rubber [IIR] vulcanizates: (a) IIR, unfilled, (b) IIR, filled with 20 phr SiO 2 , (c) IIR,filled with 20 phr SiO 2  + 1.6 phr Si69.