913765.fig.004a
(a)
913765.fig.004b
(b)
913765.fig.004c
(c)
913765.fig.004d
(d)
913765.fig.004e
(e)
Figure 4: (a) Acid degradation, (b) base degradation, (c) oxidative degradation, (d) thermal degradation, and (e) photodegradation.