Background and overview[1][2]
The binders in NEPE propellants generally use polyethylene glycol (PEG), polycaprolactone (PCL) or polycaprolactone polymer (PCP), polyethylene adipate (PGA) ), poly(ethylene oxide-tetrahydrofuran) copolyether, etc. The curing agent generally uses multifunctional isocyanate (N-100), hexamethylene diisocyanate (HDI), etc. In this type of curing system, because the isocyanate compound is highly reactive and can quickly react with water or organic acids to generate CO2, many pores are easily formed during the curing process of the propellant, which reduces the density of the propellant and affects its mechanical properties, safety and safety. Reliability also drops. One of the solutions is to use a curing system composed of terminal alkynyl compounds and azide compounds. The most commonly used adhesive is propynyl-tetrapolyethylene glycol.
Apply[3]
Propargyl-tetrapolyethylene glycol is a pharmaceutical intermediate and chemical synthesis raw material. It is an internationally popular PEGLINKER linking agent product and a binding and curing agent in NEPE propellants.
Preparation[2]
Add 1.4g potassium tert-butoxide, 2.0g tetrapolyethylene glycol, 3.0g propyne bromide and 95mL tetrahydrofuran respectively to a three-necked flask equipped with a magnetic stirrer, reflux condenser and thermometer, and provide nitrogen protection in a water bath. Heating, reaction temperature 30℃, reaction 24h. Extract with saturated saline solution, evaporate the upper layer, and dry under vacuum to obtain a viscous liquid product with a yield of 86.1%.
The obtained product is subjected to a curing reaction with an azide curing agent with a functionality of 3.82, using CuI as the catalyst and triglyceryl acetate as the plasticizer to obtain the cured product propynyl-tetrapolyethylene glycol.
Main reference materials
[1] Zou Yecheng, Qu Zhengyang, Zhai Jinxian, Guo Xiaoyan, & Yang Rongjie. (2016). Study on the kinetics of click chemical cross-linking reaction of polyether bulk terminals. Journal of Polymers (2), 219-225.
[2] Qu Zhengyang, Zhai Jinxian, Zhang Hanyu, & Yang Rongjie. (2010). Synthesis and solidification of terminal alkynyl polyethylene glycol. Journal of Explosives and Explosives, 33(6), 61-64.
[3] Guan Xin, & Li Jianmin. (2011). Research on improving the mechanical properties of GAP propellant using azido-alkyne click chemistry method. Chinese Chemical Society National Academic Conference on Chemical Propellants.
