• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.504-507
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• 2017

The polybutadiene-based HTPB used as the propellant main binder influences the curing reaction rate of the binder and propellant depending on the synthetic batch. The properties of HTPB synthesized in different batches were analyzed and applied to propellants to evaluate the curing reaction rate and mechanical properties. Finally this reaction can also affect mechanical properties of propellant. And the results suggest that proper degree of curing reaction is necessary to obtain better mechanical properties of propellant.

• Advances in materials Research
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• v.13 no.2
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• pp.129-140
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• 2024

This study evaluates the ratio of Toluene di-isocyanate (TDI) functional group isocyanate (NCO) to the binder functional hydroxyl group (OH) in HTPB/AP/Al-based propellants on their mechanical properties, flow rate, and viscosity to determine the limitations of NCO/OH in the composition of solid propellants. The propellants consisted of hydroxyl-terminated polybutadiene (HTPB) polyurethane (PU), aluminum (Al) and tri-modal ammonium perchlorate (AP). The tri-modal AP consisted of 30% of coarse AP, 30% of medium AP, and 8% of fine AP. The ratio of NCO/OH varies from 0.73 to 0.85, with two binder percentages of 10.5% and 12%. An increase in NCO/OH ratio with 10.5% binder provided 20%, 95%, and 8 to 9% increments in UTS, modulus, and hardness, respectively. However, the propellant elongation, density, and flow rate decreased by 170%, 0.2%, and 11-12%, respectively. Viscosity increased 20% based on initial hour reading. The 12% binder provides 27%, 47%, and 5~6% an increment of UTS, modulus and hardness respectively. However, the propellant elongation, density, and flow rate decreased by 47%, 0.17% and 27%, respectively. The viscosity increased 30% based on initial hour reading. This study suggests the NCO/OH value of 0.77 and 10.5~11% binder content in propellant based on the mechanical properties, flow rate, and viscosity for better processing and pot life.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.1
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• pp.84-90
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• 2017

It is observed that chemical characteristics of HTPB(Hydroxyl Terminated Polybutadiene) binder such as OH index, molecular weight and functionality and so on, can be different with synthetic batch, which can affect curing reaction of binder in itself or propellant. Finally this reaction can also affect mechanical properties of propellant. And the results suggest that proper degree of curing reaction is necessary to obtain better mechanical properties of propellant.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.441-444
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• 2011

Type A and Type B and are commercial HTPB models, which are very popular prepolymer for polyurethane binder family. So the study has been performed on the physical, chemical characteristic of HTPB and viscosity, mechanical property of PBX-A applying to HTPB. But We excluded the Type A from Appication test, because of law Hydroxyl value. And in the case of Type B, Type B-1, 2 has mechanical disadvatage to apply to HTPB in the process comparing with B-3. It seems to make no problem if we change equivalence ratio or curing condition within standards. But if we are to apply process condition like R-45HT(US-sample), it would be essential to apply HTPB with higher Hydroxyl Value and hydroxyl Functionality.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.29-34
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• 2011

Hydroxyl terminated polyether(HTPE) propellants have been developed recently as possible replacements for HTPB/AP propellants currently used in a number of tactical rocker motor. As analyzing friability of HTPE and HTPB propellants in this study, the following results could be derived. The friability of the tested propellants depended on its binder contents, mechanical property, and burning rate. It was decreased as burning rate was lowered and toughness was increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.181-184
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• 2009

A development of a composite solid propellant is carried out for an application to gas generators as an energy source of rocket system. With HTPB as a propellant binder which has 80% of particle loading ratio, a favorable rheology, and moderate curing properties at the range of $-50^{\circ}C{\sim}70^{\circ}C$, AN is selected as the first kind of oxidizer having the characteristics of a low flame temperature, minimal particle residual as well as nontoxic products. AP is the second oxidant for ballistic property control. A series of experiments for the improvement of physical properties were conducted and resulted in the propellant formulation having 30% of strain rate at 8 bar of max. stress.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.369-372
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• 2010

As analyzing friability of HTPE and HTPB propellants, the following results could be derived. The friability of the tested propellants depended on its binder contents, mechanical property, and burning rate. It was decreased as burning rate was lowered and toughness was increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.351-355
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• 2011

In this study, 2 kinds of HTPE insensitive propellants composed of HTPE/BuNENA binder, AP, AN and Al were investigated for combustion characteristics, ignition delay time, sensitivity and insensitive properties compared with HTPB propellant. HTPE propellant showed almost same sensitivity results as HTPB propellant, showed 2~3 times higher value than the value of HTPB propellant, ignition delay time respectively, and met the standard criteria, while HTPB propellant failed.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.5
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• pp.1-6
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• 2009

A development of a composite solid propellant is carried out for an application to gas generators as an energy source of rocket system. With HTPB as a propellant binder which has 80% of particle loading ratio, a favorable rheology, and moderate curing properties at the range of $-50^{\circ}{\sim}70^{\circ}C$, AN is selected as the first kind of oxidizer having the characteristics of a low flame temperature, minimal particle residual as well as nontoxic products. AP is the second oxidant for ballistic property control. A series of experiments for the improvement of physical properties were conducted and resulted in the propellant formulation having 30% of strain rate at 8 bar of max. stress.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.3
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• pp.60-70
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• 2001

The study of compatible liner with ADP-505 propellant based PCP was performed. HTPB/DDl was chosen as a binder of liner in order to prohibit migration of nitroester plasticizer from propellant. The possible formulations for liner were screened by peel test of EPDM insulation/liner, propellant/liner and insulation/liner/propellant. Also, the adhesion tests including tension and shear were conducted. The adhesion of liner and propellant fumed out to be very good. The peel value was shown 1.5∼1.8 daN/cm, tensile force was 5.5∼6.0bar and shear force was 4.2∼5.0bar. In the samples of insulation/liner/propellant, they also have shown good adhesion properties. The peel, tensile and shear strength were 1.8 daN/cm, 5.0∼6.0bar and 4.5∼5.0bar, respectively.