Isocyanate emissions from pyrolysis of mattresses containing polyurethane foam.
This study examined the emissions of powerful asthmatic agents called isocyanates from small-scale pyrolysis experiments of two common foams employed in mattress production such as flexible polyurethane foam (FPUF) and viscoelastic memory foam (VMF). A nitrogen atmosphere and five different temperatures, 300, 350, 400, 450 and 850 °C, were selected to carry out the experiments in order to evaluate the worst possible conditions for thermal degradation. A similar trend for both materials was found. At lower temperatures, diisocyanates were the most important products whereas at 850 °C monoisocyanates, and mainly isocyanic acid released mainly from the thermal cracking of diisocyanates evolved directly from the polymer chains. The total yields of isocyanates were in the range of 1.43-11.95 mg/m3for FPUF at 300-850 °C and 0.05-6.13 mg/m3for VMF, 300-850 °C. This difference could be a consequence of the lower amount of isocyanates employed in the VMF production which was confirmed by the nitrogen content of the foams, 5.95% FPUF vs. 3.34% in VMF. Additionally, a qualitative search for so far unknown isocyanates was performed in samples from the pyrolysis of FPUF at 300, 400 and 850 °C. It was confirmed that six different aminoisocyanates at 300 °C were evolved, whereas at 400 and 850 °C only five of them were detected. The general trend observed was a decrease of the aminoisocyanate levels with increasing pyrolysis temperature.
Department of Chemical Engineering, University of Alicante, P.O. Box 99, E-03080 Alicante, Spain; Empa, Swiss Federal Laboratories for Materials Sciences and Technology, Ueberlandstrasse 129, Dübendorf CH-8600, Switzerland. Electronic address: mangeles.garrido@ua.es.
María A
MA
Garrido
Arcadis Schweiz AG, Ifangstrasse 11, 8952 Schlieren, Switzerland.
Andreas C
AC
Gerecke
Empa, Swiss Federal Laboratories for Materials Sciences and Technology, Ueberlandstrasse 129, Dübendorf CH-8600, Switzerland.
Norbert
N
Heeb
Department of Chemical Engineering, University of Alicante, P.O. Box 99, E-03080 Alicante, Spain.
Rafael
R
Font
Department of Chemical Engineering, University of Alicante, P.O. Box 99, E-03080 Alicante, Spain.
Juan A
JA
Conesa
D000393:Air Pollutants / Q000032:analysis*; D001513:Beds / Q000592:standards; D004784:Environmental Monitoring / Q000379:methods*; D006358:Hot Temperature; D017953:Isocyanates / Q000032:analysis*; D008962:Models, Theoretical; D011140:Polyurethanes / Q000737:chemistry*
D000393:Air Pollutants; D017953:Isocyanates; D011140:Polyurethanes; C028279:polyurethane foam
Aminoisocyanates; Flexible polyurethane foam; Isocyanates; Pyrolysis; Viscoelastic memory foam