Flash pyrolysis of hydroxyl-terminated polybutadiene (HTPB). 2: Implications of the kinetics to combustion of organic polymers

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Combustion and Flame

DOI:https://doi.org/10.1016/0010-2180(95)00254-5· OSTI ID:264399

Arisawa, H; Brill, T B ^[1]

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1. Univ. of Delaware, Newark, DE (United States). Dept. of Chemistry

The first semi-micro kinetics analysis is described for rapid pyrolysis of an organic polymer. T-Jump/FTIR spectroscopy and structurally different hydroxyl-terminated polybutadiene polymers (HTPB) were used. The rates of formation were determined for the six most prevalent volatile products from HTPB heated at 600 C/s to constant temperatures in the 450--609 C range under 2 and 11 atm of applied pressure. The resulting Arrhenius parameters reveal that mildly exothermic, bulk-phase, heterogeneous decomposition reactions control the rate of gaseous product evolution at T < 500--530 C under 2 atm Ar. The exact temperature depends on the product and the polymer microstructure. The rate evolution of most of the gaseous products at T > 500--530 C is controlled by desorption of fragments of the polymer rather than bulk-phase decomposition. When P = 11 atm Ar, the formation and desorption of these fragments controls the rate of product of evolution over the entire 460--600 C range. These individual rate constants combined into a single rate yield macro kinetics of gas evolution from R45M as follows: E{sub a} = 51 kcal/mol, ln A (s{sup {minus}1}) = 31 for 2 atm and 450--530 C; E{sub a} = 18 kcal/mol, ln A (S{sup {minus}1}) = 11 for 2 atm and 530--609 C; E{sub a} = 12 kcal/mol, ln A (s{sup {minus}1}) = 6.6 for 11 atm and 460--600 C. A generalized equation that qualitatively matches the kinetics of gaseous product evolution as a function of pressure is given.

• OSTI ID: 264399
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 106; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CHEMICAL REACTION YIELD
COMBUSTION KINETICS
DIENES
FLASH HEATING
MATHEMATICAL MODELS
ORGANIC POLYMERS
PROPELLANTS
PYROLYSIS
ROCKET ENGINES