فصلنامه مواد پر انرژی
سال هفدهم شماره 4 (پیاپی 56، زمستان 1401)

Polycaprolactone is a polyester binder that has a polar structure and is compatible with polar plasticizer. Also, due to ester structure, oxygen balance of this polymer is more suitable than HTPB, therefore, by combining these two binders as a copolymer, the disadvantages of HTPB are eliminated and its advantages are preserved. In this research work, triblock copolymer of PCL-HTPB-PCL is made by ring opening polymerization of caprolactone by HTPB (1000 g.mol -1 ) molecular weight as a initiator and 69% yield. This copolymer was characterized by (FT-IR) and 1H-NMR spectroscopy. The investigation of the curing conditions showed that the copolymer with IPDI and N100 isocyanate in a ratio of 80: 20 were properly cured. Finally, the compatibility of cured copolymer with high energy plasticizers was investigated using swelling test and it was found that PCL-HTPB-PCL copolymer is more compatible with Bu-NENA and TEGDN plasticizers than BTTN and TMETN.

In this study, an efficient and green technique based on ultrasound-assisted extraction was developed for separation and determination of some components of double base solid propellant (DB propellant) by high performance liquid chromatography with UV detection (HPLC-UV-Vis). The optimum extraction conditions with respect to maximum recovery for target analytes were achieved at 120 min, with the power of 800 W for ultrasonic waves and dichloromethane as an extraction solvent for 0.5 gr of DB propellant sample and the recoveries for all component was near to 100%. The results of this investigation under optimum conditions were compared with the result obtained by the Soxhlet extraction method as a routine sample preparation method for DB propellant samples. The results show that the developed method is much faster and sufficient than the traditional Soxhlet extraction method. So, the developed UAE-HPLC-UV method can be used as a rapid and sensitive method for the determination of DB propellants’ constituents.

Mononitrotoluene derivatives have broad applications in textile, agriculture, pharmaceutical and military industries. These compounds are widely used as raw materials in the synthesis of other military materials such as toluidines and cresols and also as detection taggants for explosive detection. In this research, o- nitrotoluene and p- nitrotoluene derivatives have been selectively synthesized by nitration of toluene with nitric acid in the presence of some immobilized and nonimmobilized diacidic ionic liquid catalysts. The conversion of toluene was 100% in all of these reactions and no dinitrotoluene or trinitrotoluene byproduct has been produced. High yields of the products, short reaction times (2 to 4 hours), no presence of the byproducts and recoverability and reusability of the catalysts are as advantages of this method.

1,4-dinitrocyclohexane-2,3,5,6-tetranitrate is one of the strongest cyclic nitrate ester plasticizers, which is used as a new generation of plasticizers in the formulation of energetic materials. In this research, the mentioned compound was synthesized and optimized in two steps through experiment design using the Minitab 18 software (Surface Response Method) on temperature, time, and the molar ratio of reactants parameters. In the first step, 1,4-dinitrocyclohexane 2,3,5,6-tetraol was synthesized and optimized by an easy method using glyoxal and nitromethane reactants in an alkaline environment at a temperature of 10 °C for two hours, and confirmed by FT-IR and 1H-NMR spectra. In the second step, 1,4-dinitrocyclohexane-2,3,5,6-tetranitrate was synthesized with a decomposition temperature of 191 °C, and a yield of 73.56% by nitration of the 1,4-dinitrocyclohexane-2,3,5,6-tetraol with nitric acid and acetic anhydride at a temperature of 20 °C for four hours. This compound was analyzed and characterized with the help of FT-IR, 1H-NMR, and DSC-TGA.

Dimeryl diisocyanate (DDI) is a cycloaliphatic diisocyanate with a high molecular weight and a long carbon chain. The long carbon chain decrease the activity of N=C=O groups in the structure of this molecule. In this research, the synthesis of dimeryl diisocyanate (DDI) using triphosgene reagent has been investigated. Thus, in the first step, the reaction of acid dimer with thionyl chloride at ambient temperature has led to acyl chloride compound with 98% yield, and in the second step, by blowing ammonia gas, the dimeramide product was obtained with 78% yield. Then reduction of dimer amide using sodium borohydride reagent afforded dimer amine product with 52% yield. In the final step, using triphosgene reagent has led to the formation of dimeryl diisocyanate (DDI) with 62% yield. The products of different stages of the reaction were characterized using IR, 1HNMR and 13CNMR.

In double base propellants, due to inherent instability of nitroesters compunds, ageing occurs. Stabilizer using, is one of the common method in order to increase propellant's lifespan. Considering that there is no ideal stabilizer compound, stabilizer mixtures have been used to increase stability. In stabilizer mixtures, the higher eutectic point leading to lower immigration of them from propellants matrix to surface. In this research, eutectic point of five stabilizer mixtures contains (diphenylamine + ethylcentralite), (2-nitrodiphenylamine + methylcentralite), (diphenylamine + methylcentralite), (acardite II + methylcentralite) and (2-nitrodiphenylamine + ethylcentralite) were calculated as 289.31, 336.52, 294.41, 371.19 and 325.15 K, respectively. The mixture of acardite II and methyl centralite is more favorable than other mixtures due to its higher eutectic point. In the continuation of this article, the behavior of the mixed phase of stabilizers was analyzed by ideal, Wilson and UNIQUAC models. Results determined that Ideal, Wilson and UNIQUAC models can be correlated experiential melting point with maximum 11.97, 5.6 and 2.69 % error.