engleski

The utilization possibilities of waste polyurethane from household appliances

Polyurethane has a good insulation characteristic and good chemical resistance. Due to these two properties it represents an excellent insulation and lining material for refrigerators and freezers. Experimental analysis of polyurethane (PU) waste material separated into several grain size classes was performed by the method of pyrolysis gas chromatography with mass spectrometric detection (Py-GC/MS) at various pyrolytic temperatures, namely at 500, 600 and 700 °C. Waste PU contains various groups of organic compounds (aromatic hydrocarbons, alkanes, alkenes, alkadiens, hydrazines, alcohols, aldehydes and ketones, compounds containing phenols, dioxines, carboxyl acids, ethers, additives, acetates, oxysulphates, alcanoates and contaminants) in various concentrations. The most important compounds include heterocyclic compounds of nitrogen, aromatic hydrocarbons, alcohols and alcanoates. Organic compounds containing heterocyclic nitrogen, especially amines (e.g. n- ethylmorpholine, dimethylpiperazine, n, n- dimethylcyclohexanamine, n, n- dimethylbenzenmethanamine and others) belong to compounds with the highest concentrations in pyrolysates. These amines come from the catalysts during PU production. The experimental analysis found important differences in composition of amines and other compounds, in dependence on grain size composition. Unhomogenized samples produce the highest concentration of amines (˃ 40%) at the temperature of 500 °C. The temperature increase leads to the decrease of amines concentration. On the contrary, the sample homogenization leads to the significant increase of amines production. PU waste of grain size from 0.125 to 0.25 mm contained by 80% more amines with dominance of n, n-dimethylcyclohexamine. Concentrations in other grain size fractions were pronouncedly lower. The yield of amines is also influenced by temperature. Temperature increase (over 600 °C) leads to the decrease in amines concentration.

Polyurethane waste ; amines ; pyrolysis-gas chromatography

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