Preparation and Characterization of Aluminum‐Lithium Alloy Powder Coated by In‐situ Polymerization of Styrene

Abstract

Aluminum‐lithium alloy powder has broad application prospects in the field of energetic materials due to its good thermal performance. However, the high reactivity of lithium and the incompactness of the surface oxide layer result in the continuous oxidation of the active metal during storage, thereby deteriorating the thermal performance of the powder. In this paper, a layer of polystyrene (PS) was successfully coated on the surface of Al‐10Li (10 wt.%) alloy powder by in‐situ polymerization of styrene (St). According to an orthogonal test, the optimum coating conditions for protection factor were as follows: m(St)/m(Al‐10Li) was 1 : 1; m(AIBN)/m(St) was 5 %; the reaction temperature was 75 °C; the reaction time was 4 h. The structure, surface morphology and thermal properties were characterized by XPS, FTIR, SEM and TG‐DTA. Furthermore, the aging stability of powders were studied by TG‐DTA. The results showed that the decay rate of the weight increase of the active metal of Al‐10Li alloy powder decreased significantly after coating, which demonstrated that the polystyrene coating effectively protected the active metal of Al‐10Li alloy powder, prevented pre‐oxidation of Al‐10Li alloy powder in air and improved its storage stability.

Constructing α-AlH3@polymer composites with high safety and excellent stability properties via in situ polymerization

“…4 (b)). 36 The C1s binding energy of α-AlH 3 @PMA could be fitted into three peaks located at 284.7 eV, 285.8 eV, and 288.8 eV (Fig. 4 (c)), which could be ascribed to CH 2 –CH, CH 3 –O, and CO in the polymethyl acrylate structural unit, respectively.…”

“…The high-resolution XPS spectra scanning results of C1s of a-AlH 3 and a-AlH 3 @polymer composite are shown in Fig. 4 36 The C1s binding energy of a-AlH 3 @PMA could be fitted into three peaks located at 284.7 eV, 285.8 eV, and 288.8 eV (Fig. 4(c)), which could be ascribed to CH 2 -CH, CH 3 -O, and CQO in the polymethyl acrylate structural unit, respectively.…”

“…35 In this way, the activity of energetic materials could be retained to a great extent and the dispersibility of the material could be further improved. 36 Moreover, due to the low melting point of the polymer, the polymer layer could burn rapidly at high temperatures, so that the energy of the energetic materials could be released rapidly. 37 Studies showed that different explosives (RDX, HMX, and CL-20) could be successfully and completely coated by in situ polymerized melamine-formaldehyde (MF) resins.…”

“…37,39 The PDA interfacial binding layer could prevent further oxidation of n-Al and lead to higher combustion efficiency of n-Al. Cai et al 36 effectively protected the activity of the Al-10%Li alloy powder from oxidation in the air. Its storage stability was improved by the in situ polymerization of styrene coating.…”

Energetic and Protective Coating via Chemical and Physical Synergism for High Water-Reactive Aluminum Powder

“…To improve stability against oxidation of aluminum powder in storage, hydroxyl terminated polybutadiene–toluene diisocyanate (HTPB-TDI) was used to coat aluminum powder [ 11 ]. Cao, et al [ 12 ] coated an aluminum–lithium alloy by in situ polymerization of styrene to improve stability. Tran, et al [ 13 ] coated (3-aminopropyl) triethoxysilane on the surface of aluminum powder to improve the oxidation resistance and stability in water.…”