This work discusses different roles of nano-silica in the kinetics of peroxide vulcanization of ethylene propylene diene (EPDM) rubber for the first time. Initially, it was shown that silica does not participate in the vulcanization mechanism by chemical bonding to other intermediates. Non-isothermal differential scanning calorimeter revealed that the enthalpy of vulcanization, proportional to the crosslinking reaction, goes through a minimum as silica loading increases. Therefore, silica has two roles affecting kinetics of peroxide vulcanization of EPDM: physical effect on the rate of crosslinking reaction through reduced dynamics of rubber chains and catalytic effect on the decomposition of peroxide. In the low-temperature isothermal vulcanization, the enthalpy of vulcanization decreased monotonically, indicating that the physical effect is dominant. The extent of physical effect was correlated to the immobilized bound rubber resulting from the filler-polymer and filler-filler interactions. However, at high-temperature isothermal or non-isothermal vulcanization, the catalytic effect surmounts the physical one.

这项工作首次讨论了纳米二氧化硅在乙丙二烯（EPDM）橡胶的过氧化物硫化动力学中的不同作用。最初显示，二氧化硅不通过与其他中间体的化学键合而参与硫化机理。非等温差示扫描量热仪显示，随着二氧化硅载量的增加，硫化的焓与交联反应成正比，最小化。因此，二氧化硅具有影响EPDM的过氧化物硫化动力学的两个作用：通过降低橡胶链的动力学对交联反应速率的物理影响和对过氧化物分解的催化作用。在低温等温硫化中，硫化焓单调降低，表示身体效应占主导地位。物理作用的程度与由填料-聚合物和填料-填料相互作用产生的固定结合橡胶相关。然而，在高温等温或非等温硫化下，催化作用胜过物理作用。