Polyisobutylene, bond breaking

Empirical rate equations have been reported for the mastication degradation of many polymers, for example, polyethylene [29], poly(methyl methacrylate) [30], styrene rubbers [31, 32], polychloroprene [33], and EPDM [34]. Reaction rate generally depends on [35]. Experiments on degradation rate have been performed also on the molten state [15, 16, 35]. Pohl and co-workers [15, 16] reported their data as the fraction of bonds broken (Eq. 2.17) as a function of capillary residence time. They found that the average rate of bond breaking b depends on shear rate y and absolute temperature T by the following equation for polyisobutylene ... 

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