*Microwave-Assisted Pyrolysis Process: From a Laboratory Scale to an Industrial Plant DOI: http://dx.doi.org/10.5772/intechopen.104925*

**Figure 17.** *TGA analysis of single-use mask.*


#### **Table 5.**

*Physical characteristics of liquids obtained from MAP of plastics.*

microwave power used. The highest amount of styrene was present in PS2 and PS4 (respectively 52.8 and 56.9%), corresponding to experiments where a higher microwave power was used. In contrast, using a lower microwave power (PS1, **Table 7**), the amount of styrene was drastically reduced. Also, as reported above for PS, the MAP of ABS gives a liquid fraction with a density between 0.97 and 1.02 g/cm3 and C/H molar ratio of 0.85 wt% indicative of the prevailing presence of aromatic compounds. The liquid fraction was analyzed by GC–MS, a complete list of compounds identified through the NIST library is reported in **Table 8**. Aryl compounds, especially styrene, are present in large amounts in the liquid from MAP of ABS. In the presence of acrylonitrile, nitrile compounds such as 2-methylenpropionitrile were formed in a significant amount. MAP of PP gave a low-density liquid (0.746–0.760 g/cm3 ) and a C/H molar ratio of 0.5 wt%, confirming the prevailing presence of aliphatic compounds in this liquid. The main compounds identified in the liquid from MAP of PP are reported in **Table 9**, they were branched saturated and unsaturated hydrocarbons, which wereformed through C-C bond cleavage of the PP backbone. In particular, there was


#### **Table 6.**

*Main compounds identified in liquid from MAP of PS4, by GC–MS.*


#### **Table 7.**

*Correlation between styrene in liquid and MW power in the MAP of PS.*


#### **Table 8.**

*Main compounds identified in liquids from MAP of ABS, by GC–MS.*

a prevalence of C9-C12 hydrocarbons, and among these, the 2,4-dimethyl-1-hepthene was found as the main compound, in agreement with previous results [8]. Many other compounds were present in very low amounts and reported as others. The presence of aromatic hydrocarbons was attributed to cyclization and aromatization reactions of unsaturated compounds formed during the MAP process as reported.

*Microwave-Assisted Pyrolysis Process: From a Laboratory Scale to an Industrial Plant DOI: http://dx.doi.org/10.5772/intechopen.104925*


#### **Table 9.**

*Compounds identified in liquids from MAP of PP, by GC–MS.*

The facemasks were converted into the classical three products of a MAP (liquid, small amount of solid, and gas), having a composition close to those reported in the pyrolysis of PP. The possible contamination was absent in the products formed due to the pyrolysis conditions adopted.
