Synthesis of HTPB using a semi-batch method

Hydroxyl-terminated polybutadiene is widely used in industry for both civil and military applications. In munitions, HTPB is mostly used as a binder for heterogenic rocket propellants and as a component of plastic bonded explosives, as well as a phlegmatizer in explosives sensitive to friction and impact. The wide range of HTPB applications results from the good mechanical properties of HTPB-based polyurethanes, in particular at temperatures down to –40 °C. A synthesis method for HTPB, different from the commonly used semi-batch and continuous methods, is presented. The effect of parameters including reaction temperature, 1,3-butadiene pressure and hydrogen peroxide concentration on the properties of the obtained polymer is determined. The synthesis conditions enabling new HTPB species to be obtained, which meet the requirements for binders used in solid rocket propellants, are specified.

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Influence of different crosslinking mixtures on the mechanical properties of composite solid rocket propellants based on HTPB

High Performance Polymers ◽

10.1177/0954008320940359 ◽

2020 ◽

pp. 095400832094035

Author(s):

Islam K Boshra ◽

Guo Lin ◽

Ahmed Elbeih

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Crosslinking Agent ◽

Weight Ratio ◽

High Strength ◽

Rocket Propellants ◽

Wide Range ◽

Solid Rocket ◽

Solid Rocket Propellants ◽

Composite Solid

The crosslinking agent is a vital key which affects the mechanical properties of composite solid rocket propellants (CSRPs). Under this scheme, the effect of crosslinking mixtures (CMs) based on trimethylolpropane (TMP) as a triol crosslinker and butanediol (BD) as a chain extender on CSRPs based on hydroxyl-terminated polybutadiene was investigated. A series of 27 propellant compositions was formulated to study the mechanical properties of the prepared CSRPs. The effect of changing the weight ratio of TMP to BD in the CM was studied. In addition, the influence of increasing the percentage of CM (from 0% to 0.5%) in the prepared samples was investigated. Also, the effect of the CM on CSRPs containing different curing ratio of NCO/OH = 0.7, 0.75, and 0.8 was studied to generate the largest possible strain-ability with high strength over different levels of curing conditions. The mechanical characteristics (tensile strength and strain) of the prepared CSRPs have been measured and plotted versus CM content, NCO/OH and TMP:BD ratio. Generally, the addition of CM leads to a remarkable enhancement in the propellant mechanical properties. Samples containing TMP:BD (2:1) provide the highest strength while samples containing TMP:BD (1:2) show the highest strain over all the NCO/OH ratios. Formulations with TMP:BD (1:1) give high strength with moderate strain. Variation in CM content has a remarkable influence on the mechanical properties of CSRPs. A wide range of tensile strength and strain were obtained from this study to offer variety of results suitable for different applications in the CSRPs technology.

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An analysis of the mechanical properties of HTPB-propellants using DMA

Materiały Wysokoenergetyczne / High Energy Materials ◽

10.22211/matwys/0192 ◽

2020 ◽

pp. 81-91

Author(s):

Katarzyna Gańczyk-Specjalska ◽

Paulina Magnuszewska

Keyword(s):

Mechanical Properties ◽

Glass Transition ◽

Transition Temperature ◽

Mechanical Analysis ◽

Thermomechanical Properties ◽

Dynamic Force ◽

Rocket Propellants ◽

Hard Segments ◽

Solid Rocket ◽

Solid Rocket Propellants

The paper presents the thermomechanical properties of solid rocket propellants containing hydroxyl-terminated polybutadiene. Dynamic mechanical analysis (DMA) was used in analysing the mechanical properties of propellant for two different sample geometries (cuboid and cylindrical). Nonisothermal and isothermal analyses were carried out in two holders: dual-cantilever and compression. The glass transition temperature of soft and hard segments in the propellants, the effect of dynamic force on sample strain, the creep-relaxation process (based on which parameters in the Burgers model were calculated) were determined based on the results of the analysis.

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