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The rejected fraction of plastics from different sorting plants has been studied in terms of composition, processability and enhancement potential. This waste stream consists of a coarse range of plastics families, polyethylene constituting the most abundant one. Blends with two recycled polyethylenes in different proportions were analyzed. The results showed that the mixed fraction was easy to process although it showed a brittle behavior. The addition of recycled polyethylene caused limited ductility improvements, although acceptable levels were achieved in certain mixing ratios. This work demonstrates that mixed plastic wastes can be transformed into a useful material.

Thermooxidative degradation at and beyond processing temperatures of a polyoxymethylene copolymer has been progressively accelerated to carbonisation through oven-storage aging. The quantification of such degradation was carried out through FTIR spectrography and colour spectrophotometry methods. The state of thermo-oxidation was monitored through the FTIR spectra corresponding to the carbonyl aldehyde group (O=CH) and methylene bending (–CH2), as well as the chromaticity changes experienced on the sample surface. The results showed that the FTIR bands suggested are a reliable indicator during the initial conditions of degradation, however, the spectrophotometry becomes more appropriate method for more aggressive conditions leading to carbonisation.