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The thermal decomposition of polyurethanes and polyisocyanurates
Author(s) -
Chambers John,
Jiricny Josef,
Reese Colin B.
Publication year - 1981
Publication title -
fire and materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.482
H-Index - 58
eISSN - 1099-1018
pISSN - 0308-0501
DOI - 10.1002/fam.810050402
Subject(s) - polyurethane , nitrile , thermal decomposition , isocyanate , decomposition , chemistry , carbon fibers , yield (engineering) , organic chemistry , polymer chemistry , materials science , composite material , composite number
The thermal decomposition of a number of TDI‐ and MDI‐based biscarbamates (model compounds for polyurethane foams) between 200°C and 1000°C showed that the urethane linkage undergoes an O ‐acyl fission at about 300°C to generate the free isocyanate and alcohol. In the case of the flexible foam analogues, the newly generated TDI reacts further to generate volatile polyureas, termed ‘yellow smoke’. The MDI residues generated in the decomposition of a rigid foams react to yield non‐volatile polycarbodiimides. Both the yellow smokes and the polycarbodiimides decompose above 600°C to give a mixture of nitriles (including HCN) as well as a number of olefinic and aromatic compounds. The use of 13 C labeling indicated that HCN and all the other nitriles generated during the high temperature decompositions originate in the thermal fission of the aromatic ring, the nitrile carbon being the 2‐, 4‐ or 6‐ carbon of MDI.