By examining the TG curve, a sharp mass
decrease can be observed at 390°C, corresponding to
the thermal degradation, as it is confirmed by the
appearance of the Gram Schmidt plot which sums the
IR signal intensities of the gaseous products; the
TG/FT-IR diagram puts in evidence that thermal
degradation occurs in a single step. Besides, the TG
curve shows a remarkable residue amount around
22% w/w, which can be attributed to the production
of conjugated aromatic rings and the high
concentration of flame retardants used in the slots of
PCBs (Cafiero et al., 2014). Fig. 5 shows the results
of simulated PC sample which is mainly made up
with styrene-based polymers. Thermal degradation
occurs at 422°C leaving a low residue amount (less
than 2% w/w).
IR spectrum of evolved gases from black slot
sample pyrolysis is reported in Fig. 6. The bands
around 2870 and 2981 cm-1 are characteristic of the
presence of aromatic ring or substituted phenyl ring.