# Characterization and Use of Char Produced from Pyrolysis of Post-Consumer Mixed Plastic Waste
## 3 Results and Discussion  
Identification and Characterization of the Main Polymers Existing in the Non-Recyclable Mixed Plastics Bales from Municipal Solid Waste  
1.1 Identification of the Main Polymers Existing in the Non-Recyclable Mixed Plastics Bales from Municipal Solid Waste  
The results obtained from the evaluation of the composition and characteristics of the non-recyclable plastics (the feedstock of the work) containing in the municipal solid waste (fraction non-recovery selectively) are shown in Table 1. \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{2}{c}{**Fraction**} & **Content, \%** \\ \hline \multicolumn{2}{c}{**PP**} & 28.9 \(\pm\) 3.6 \\ \hline \multirow{8}{*}{PS} & GPPS & 1.6 \(\pm\) 0.4 \\ \cline{2-3}  & HIPS & 2.9 \(\pm\) 1.2 \\ \cline{2-3}  & EPS & 3.4 \(\pm\) 0.9 \\ \cline{2-3}  & XPS & 1.2 \(\pm\) 0.0 \\ \cline{2-3}  & Others & 0.6 \(\pm\) 0.4 \\ \cline{2-3}  & Total PS & 9.7 \(\pm\) 1.4 \\ \hline \multicolumn{2}{c}{PET} & 22.0 \(\pm\) 0.8 \\ \hline \multicolumn{2}{c}{PE} & 4.7 \(\pm\) 1.6 \\ \hline \multicolumn{2}{c}{Film} & 13.4 \(\pm\) 2.3 \\ \hline \multicolumn{2}{c}{Paper and cardboard} & 5.2 \(\pm\) 2.5 \\ \hline \multicolumn{2}{c}{Organic matter} & 0.9 \(\pm\) 0.2 \\ \hline \multicolumn{2}{c}{Fines} & 4.2 \(\pm\) 1.3 \\ \hline \multicolumn{2}{c}{Others} & 11.1 \(\pm\) 2.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Results of the identification of the polymers presented in the bales of non-recyclable mixed plastics from municipal solid waste. The most abundant material in mixed plastic bales is PP, followed by PET, film, PS (where EPS and HIPS are fractions predominate) and finally PE. These five fractions represent approximately 75-80% of the bale, which means that only 20% of the bale would be wasted. There are also other fractions based on \"Others\" which, although they have a significant percentage, are made up of materials of a different nature and are difficult to classify and separate. Few references have been found in the literature on the specific characterization of mixed plastic bales from the reject fraction of a municipal solid waste treatment plant, although there are some references that study the composition of municipal solid waste in general. In Spain, a study was carried out by [PERSON] et al. [5; 6], specifically in Amorebieta (Bilbao), which shows the composition of the reject fraction of a waste sorting plant, which represents 27% of the input material of the plant and is sent for incineration. These researchers found that polypropylene (PP) and high-density polyethylene (HDPE) are the most abundant polymers with 31.25% each, followed by EPS with 13.5% and PET with 11.46%. [PERSON] et al. [1] studying the co-pyrolysis of pine forest biomass, used tire rubber and plastic waste, found that the composition of the plastics fraction from municipal solid waste in a region of Portugal consists of 56% PE, 27% PP and 17% PS. The research by [PERSON] et al. [37] using municipal waste plastics from a region in Hungary, reported a composition of 59.1% PE, 25% PP, 7.2% PS and 8.7% others (PET, PVC, PA, ABS). [PERSON] et al. [38] used plastic waste from a recycling company which collects, separates and recycles post-consumer plastics and tested two different mixtures, both consisting of HDPE, LDPE, PP and PS, but in different proportions. Mix 1 simulated the composition of the percentages of each type of plastic found in waste in Europe, being HDPE (22%), LDPE (31%), PP (35%) and PS (12%) and mix 2 simulated a real mixture of waste plastics found in the world, being HDPE (28%), LDPE (37%), PP (35%) and PS (0%). In addition, [PERSON] et al. [4] found that the proportion of plastic waste present in municipal solid waste in one region of Hungary was 35% LDPE, 32% HDPE, 24% PP, 4% PVC, 5% others. [PERSON] and [PERSON] [2] obtain similar results, since the majority of the fractions they find in municipal solid waste in India are LDPE, HDPE and PP, although they do not specify percentages of each type of material. [PERSON] et al.