Thermal Degradative Behavior of Selected Urethane Foams Related to Variations of Constituents Part II. Chemical Reactions in Urethane Decomposition

Tilley, James N.; Nadeau, Hendrickje; Reymore, H.E.; Waszeciak, P.H.; Sayigh, A. A. R.

doi:10.1177/0021955x6800400202

Cited by 11 publications

(7 citation statements)

References 11 publications

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“…An apparent activation energy of 52 Kcal/mole was calculated. Because this value obtained for the activation energy is similar in magnitude to the values found for other materials with oxygen containing functional groups [2,8], this excercise serves as a check on the ability of the Instrumentation to function as a crude probe for the degradation kinetics. An attempt at estimating the activation energy of the first major stage by the procedure above was not successful.…”

Section: Following the Example Of Mccartersupporting

confidence: 61%

“…And we have also determined thaL the first major stage contains essentially all of the readily condensable pyrolysis products. These stages of course would be expected when the proposed degradation mechanism of the ure thane group is considered [1,2,3].…”

Section: Rate Of Pyrolyzate Evolutionmentioning

confidence: 96%

“…In the postulated mechanism [1,2] for degradation of polyurethane the products include inert substances such as CO2 as a major component which is produced in the first stage of the degradation process.…”

Section: Following the Example Of Mccartermentioning

confidence: 99%

“…The two major stages of polyurethane degradation are illustrated with the postulated mechanism [1][2][3][4][5] in the following scheme:…”

Section: Following the Example Of Mccartermentioning

confidence: 99%

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A technique for the measurement of flash fire potential of polymeric materials

Brown¹,

Comeford²

1975

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This report summarizes work for the period February-August 1974 on a continuing program to characterize the chemical and physical parameters of importance in a flash fire and to develop laboratory scale methods for measuring the flash fire potential of materials. Significant modifications have been made to a flash fire cell developed earlier to measure the flash fire potential of materials by characterizing the conditions required to produce an ignitable pyrolyzate-air mixture by thermally degrading a polymer. The furnace temperature, cell geometry and orientation, and sample size are specified. These modifications have resulted in an improved technique, especially in terms of reproducibility, for evaluation of flash fire potential of materials. Experiments have been conducted on rates of combustible gas formation from flexible polyurethanes to assist in the optimization of the flash-fire cell operating conditions. In the rate study, two successive major stages of degradation were found for polyurethane as the temperature approached 500°a t a rate of about 60°C/min. It was also found that the products of the second stage appear to be responsible for flash fires in the flash-fire cell. A minimum polyurethane weight to enclosure volume ratio greater than 0.2 g/1 and a sample pyrolysis temperature greater than 380°C were required to produce a flash fire in this apparatus.

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Section: Following the Example Of Mccartersupporting

confidence: 61%

Section: Rate Of Pyrolyzate Evolutionmentioning

confidence: 96%

Section: Following the Example Of Mccartermentioning

confidence: 99%

“…The two major stages of polyurethane degradation are illustrated with the postulated mechanism [1][2][3][4][5] in the following scheme:…”

Section: Following the Example Of Mccartermentioning

confidence: 99%

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A technique for the measurement of flash fire potential of polymeric materials

Brown¹,

Comeford²

1975

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“…Likewise, as the 16 temperature is decreased, the gas pressure decreases and the foam has a tendency to contract,, The better the foam can resist such gas pressure changes, the more dimensionally stable it is. The ability of the foam to resist these changes is governed by the foam density, the cell structure, and the polymer composition [15] decomposition has been studied and it is known that there are three major reaction pathways for decomposition [20] . This chemistry is important for it is through the use of such knowledge that the polymer chemist may modify the polymer to increase stability.…”

Section: Properties Of Rigid or Structural Foamsmentioning

confidence: 99%

Guidelines for selection of and use of foam polyurethane roofing systems

Cullen¹,

Rossiter²

1972

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The thermal decomposition of polyurethanes and polyisocyanurates

1981

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The thermal decomposition of a number of TDI-and MDI-based biscarbamates (model compounds for polyurethane foams) between 200 "C and lo00 "C showed that the urethane linkage undergoes an 0-acyl fission at about 300 "C to generate tbehee isocyanate and alcohol. In the case of the flexiie foam analogues, the newly generated T D I reacts fnrtber to generate volatile polyureas, termed 'yellow smoke'. The MDI residues generated in the decompasition of a rigid foams react to yield non-volatile polycarbodhides. Both the yellow smokes and the polyearboamnr 'des decompose above 600 "C to give a mixture of nitriles (iidnding HCN) as well as a number of ole6nic and aromatic compounds. The use of -C labelling indicated that HCN and all the other nitrites generated during the hi& temperature decompositions originate in the thermal fission of the aromatic ring, the nitrile carbon being the 2-, 4-or 6-carbon of MDI. INTRODUCllON

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Thermal Degradative Behavior of Selected Urethane Foams Related to Variations of Constituents Part II. Chemical Reactions in Urethane Decomposition

Cited by 11 publications

References 11 publications

A technique for the measurement of flash fire potential of polymeric materials

A technique for the measurement of flash fire potential of polymeric materials

Guidelines for selection of and use of foam polyurethane roofing systems

The thermal decomposition of polyurethanes and polyisocyanurates

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