ABSTRACT
Both types of degradation can occur simultaneously or only one of them may occur, depending on (a) the nature of the polymer, (b) the temperature and some other factors. The relative importance of these two processes can be deduced from MW versus percentage of degradation to monomer curves. Figure 8.3 idealizes three distinct types of behaviour. Degradation via a route exactly the reverse of polymerization corresponds to line A-C. In such a case, the chains unzip in a rapid reaction when activated. Pure random chain scission would be represented by line A-B. As noted previously, the MW of the polymer drops rapidly until a very low average MW is reached. Line A-D corresponds to the rupture of the bonds near chain ends.
