Chain reactions of chemical decomposition forming free radicals can
promote the formation of micro-cracks and/or surface hardening. The
orientation of the phases would be beneficial to the increase in the
mechanical properties. In this way, the molecular weight, gel content,
and thermal analyses were investigated.
The average weight molecular weight (𝑀𝑤) and polydispersion (𝑀𝑤/𝑀𝑛),
obtained through the surface region GPC curves, before and after UV
irradiation, are shown in Figure 3. A tendency of molecular weight
reduction was observed, as a variation of polydispersion in the
investigated times. This behavior was also reported by other researchers
in distinct works on degradation process [19].