Hydroxyl-terminated polybutadiene (HTPB) is a common ingredient in rocket propellants, but its thermochemical properties (composition, density, and heat of formation) are not well defined. A survey of the literature and thermochemical databases indicated wide ranges for these properties, especially heat of formation. Six group additive schemes were used to estimate the heat of formation of HTPB and analyze the effects of hydroxyl functionalization and curing reactions. Good agreement is observed between the methods for HTPB isomer units, but cumulative differences result in significant disparities for larger, practical polymers. Increased hydroxyl functionality and the curing reaction are predicted to yield nonnegligible decreases in the heat of formation. The heat of formation of propellant-grade, isophorone-diisocayante-cured HTPB R-45M ( C 213.8 H 323.0 O 4.6 N 2.3 ) was computed as 342    kJ / mol or 114    kJ / kg . Chemical equilibrium analyses were completed for solid propellants composed of ammonium perchlorate and HTPB, and for hybrid rocket engines based on HTPB burning with liquid oxygen or nitrous oxide, where the heat of formation of HTPB was varied within a reasonable range. The chemical equilibrium analysis computations indicated that combustion gas properties and theoretical propellant performance can vary up to 5% within practical operating conditions for the range of HTPB heats of formation implemented.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    HTPB Heat of Formation: Literature Survey, Group Additive Estimations, and Theoretical Effects


    Contributors:

    Published in:

    AIAA Journal ; 60 , 3 ; 1269-1282


    Publication date :

    2021-10-11


    Size :

    14 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English






    HTPB Propellant Aging

    A.G. Christiansen / L.H. Layton / R.L. Carpenter | AIAA | 1981


    Aging of HTPB Propellant

    Kivity, Moshe / Hartman, Gadi / Achlama, Abraham | AIAA | 2005


    HTPB Combustion Temperature Measurements

    Geipel, Clayton M. / Pfutzner, Christopher J. / Fisher, Brian T. | TIBKAT | 2023