Influence of Acidic Impurities on Rheological Properties of Boron/Agglomerated Boron and HTPB Slurry

Abstract

The rheological properties of HTPB mixed with boron (B) or agglomerated boron (TB) were investigated to explore the effect of the impurities of boron on the processing of propellant. The phase structure, morphology, and acidity of each sample were characterized by XRD, SEM and pH, respectively. The results show that rheological property of B/HTPB can be significantly improved by agglomerating boron with binder. Time has little effect on the viscosity of TB/HTPB while that of B/HTPB is a strong function of time. The viscosity of TB/HTPB decreases when the temperature increases from 303K to 343K, while that of B/HTPB decreases from 303K to 323K and then increases sharply after 323K. After agglomerating with binder, theTonsetof boron reduces from 1056K to 954K andTpdrops from 1076K to 998K. Compared with B2, the weight gain and oxidation degree of TB2 increases by 27% and 8.5%, respectively.

Dual-core–shell structure B@LiF@AP with multi-effect synergies to improve processibility and energy release characteristics of B

“…[15][16][17][18] However, boric acid (H 3 BO 3 ) and boron oxide (B 2 O 3 ) on the surface of B and combustion product B 2 O 3 cause many problems (ignition, combustion and processibility) during the application of B. 17,[19][20][21] Owing to the extremely different melting point (450 °C) and boiling point (1860 °C) of B 2 O 3 , there is a layer of liquid B 2 O 3 during B combustion. 22 The diffusion rate of oxidizing components in liquid B 2 O 3 is very slow that inside active B cannot have contact with the oxide component, which causes B to be difficult to ignite and burn completely.…”

“…[23][24][25][26][27] Moreover, B is a typical electron-decient atom, as shown in Scheme 1, which makes the dehydration crosslinking reaction of B 2 O 3 and H 3 BO 3 with hydroxyl prepolymer easy to occur. 20,21 Lithium uoride (LiF) can decompose B 2 O 3 into the gaseous product LiBO 2 and BOF at a lower temperature (about 600 °C), as shown in eqn (1), which can improve the ignition and combustion performance of B. 28 Ammonium perchlorate (AP) is an oxidant commonly used in boron-based fuel-rich propellants and has good compatibility with hydroxyl prepolymer.…”

“…Moreover, B is a typical electron-deficient atom, as shown in Scheme 1, which makes the dehydration crosslinking reaction of B 2 O 3 and H 3 BO 3 with hydroxyl prepolymer easy to occur. 20,21…”