Pot life extension of hydroxyl terminated polybutadiene based solid propellant binder system by tailoring the binder polymer microstructure

Sekkar, V.; Alex, Ancy Smitha; Kumar, Vipin; Bandyopadhyay, G. G.

doi:10.1080/10601325.2017.1265403

Cited by 12 publications

(12 citation statements)

References 8 publications

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“…where k is the aging reaction rate constant; t is the aging time; ν0 and α are the constants. The Levenberg-Marquardt optimization algorithm [35,36] was used for parameters fitting in Equation (1). The fitting results are shown in Table 1 and the fitting curve is shown in Figure 3.…”

Section: Aging Results Of Crosslinking Densitymentioning

confidence: 99%

“…A polyurethane network system based on hydroxyl terminated polybutadiene (HTPB) has been widely used in composite solid propellant, adhesive, sealant, coating, and so on, because of its convenient processing and good mechanical properties [1]. HTPB coating is mainly used in the solid rocket motor; however, the aging phenomenon exists during the storage process, which will directly affect the service life of an HTPB coating.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Thermally-Accelerated Aging on the Dynamic Mechanical Properties of HTPB Coating and Crosslinking Density-Modified Model for the Payne Effect

Zheng

2020

Polymers

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Hydroxyl terminated polybutadiene (HTPB) coating is widely used in a solid rocket motor, but an aging phenomenon exists during long-term storage, which causes irreversible damage to the performance of this HTPB coating. In order to study the effect of aging on the dynamic mechanical properties of the HTPB coating, the thermally-accelerated aging test was carried out. The variation of maximum elongation and crosslinking density with aging time was obtained, and a good linear relationship between maximum elongation and crosslinking density was found by correlation analysis. The changing regularity of dynamic mechanical properties with aging time was analyzed. It was found that with the increase of aging time, T g of HTPB coating increased, T α , tan β and tan α decreased, and the functional relationships between the loss factor parameters and crosslinking density were constructed. The storage modulus and loss modulus of HTPB coating increased with the increase of aging time, and decreased with the increase of pre-strain. The aging enhanced the Payne effect of HTPB coating, while the pre-strain had a weakening effect. In view of the Payne effect of HTPB coating, the crosslinking density was introduced into Kraus model as aging evaluation parameter, and the crosslinking density modified models with and without pre-strain were established. The proposed models can effectively solve the problem that the Kraus model has a poor fitting effect under the condition of small strain (generally less than 1%) and on the loss modulus, which have improved the correlations between the fitting results and the test results.Polymers 2020, 12, 403 2 of 20 of 1 H NMR (nuclear magnetic resonance), and analyzed the influence of the crosslinking density on the macro-mechanical properties.It was found that with the increase of crosslinking density, the hardness and modulus of the material increased linearly, while the elongation at break decreased linearly. Katarzyna et al. [5] found that the existence of crosslinking resulted in the increase of the glass transition temperature T g . Actually, the linear relationship equation between T g and crosslinking density was derived in the study of Fox and Loshaek [6]. Although the linear equation was not completely consistent with some later results [7-9], they also came to the same conclusion that the crosslinking can increase the glass transition temperature of the polymer. In the study of Celina et al. [10], it was found that the crosslinking density of HTPB elastomers increased with the aging time. The mainly aging reaction was oxidation crosslinking, and the change of crosslinking density affected the mechanical properties of the material. Byungwoo et al. [11] also got the same conclusion. The test results demonstrated that the crosslinking density increased with the increase of aging temperature and aging time, and the crosslinking changed with the change of aging condition. The functional relationship between strain energy density and crosslinking density was established.Dynamic mechanical ...

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Section: Aging Results Of Crosslinking Densitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Thermally-Accelerated Aging on the Dynamic Mechanical Properties of HTPB Coating and Crosslinking Density-Modified Model for the Payne Effect

Zheng

2020

Polymers

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“…G‐type hydroxyls represent the tri‐functional components and, therefore, contribute towards crosslinking in a cured system. The kinetics of urethane formation for G‐type hydroxyls is the fastest [38]. A higher F h usually indicates a larger proportion of G‐type hydroxyl groups.…”

Section: Resultsmentioning

confidence: 99%

“…The polymer having high F h value is associated with high average functionality. High average functionality would in‐turn cause more branching reactions, faster curing, lower elongation and higher modulus [38]. Polymers having low F h behave oppositely.…”

Section: Resultsmentioning

confidence: 99%

Tailoring of Mechanical Properties of Highly Filled Nano‐Aluminized Propellants by Modifying Binder Polymer Microstructure

Sanyal

Chakravarthy

Ramesh

et al. 2020

Propellants Explo Pyrotec

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Use of nano sized aluminium powder in place of micron sized powder leads to increase in specific impulse of solid composite propellants. However, poor mechanical properties of nano-aluminized propellants prevent their use in actual rocket motors. An attempt has been made here, to improve the mechanical properties by using different HTPB resins having different functionality type distribution. Adjustment of isocyanate to hydroxyl ratio, and ratio of the chain extender, Butane-diol, to the cross-linker, Tri-Methylol-Propane, had also been tried to investigate their effect on mechanical properties. Nano-aluminium content in the propellant samples could be raised to the conventional level of 18 % by use of Iso Decyl Pelargonate as plasticizer in place of Dioctyl Adipate. This made the samples at par with the conventional micro-aluminium propellants, and the experimental results comparable. The microstructural changes of HTPB significantly improved the tensile strength of the nano-aluminium propellants to 0.65 MPa and break elongation to 17 % respectively. Recorded heat of combustion values are at 5990 J/g. These figures meet industrial tolerance and make the propellant acceptable for use while increasing its specific impulse beyond today's conventional levels. The technology established has potentials to increase nano-aluminium content further, and augment ballistic properties of solid motors, upholding the required industrial restrictions of rheological and physico-mechanical parameters.

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“…1,2 Recently, an important development was reported of the application of HTPB in the eld of solid rocket propellants. [3][4][5][6][7][8][9][10][11][12] Usually, three different segment structures in the HTPB backbone are detected; they are cis-1,4 unit, trans-1,4 unit and 1,2 unit as shown in Scheme 1. Due to these structures, different physical and mechanical properties can be observed.…”

Section: Introductionmentioning

confidence: 99%

Influence of mono-lithium based initiators with different steric volumes on 1,4 unit content of hydroxyl terminated polybutadiene using anionic polymerization

et al. 2017

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Pot life extension of hydroxyl terminated polybutadiene based solid propellant binder system by tailoring the binder polymer microstructure

Cited by 12 publications

References 8 publications

Influence of Thermally-Accelerated Aging on the Dynamic Mechanical Properties of HTPB Coating and Crosslinking Density-Modified Model for the Payne Effect

Influence of Thermally-Accelerated Aging on the Dynamic Mechanical Properties of HTPB Coating and Crosslinking Density-Modified Model for the Payne Effect

Tailoring of Mechanical Properties of Highly Filled Nano‐Aluminized Propellants by Modifying Binder Polymer Microstructure

Influence of mono-lithium based initiators with different steric volumes on 1,4 unit content of hydroxyl terminated polybutadiene using anionic polymerization

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