Impact-Induced Reaction Characteristic and the Enhanced Sensitivity of PTFE/Al/Bi2O3 Composites.

Ying Yuan,Qingbo Yu,Haifu Wang,Baoqun Geng,Tao Sun

doi:10.3390/polym11122049

Abstract

In this paper, the reaction characteristic of a novel reactive material, which introduced bismuth trioxide (Bi2O3) into traditional polytetrafluoroethylene/aluminum (PTFE/Al), is studied. The effect of Bi2O3 with different content and particle size on the reaction behaviors of PTFE/Al/Bi2O3 are investigated by drop-weight test and X-ray diffractometer (XRD), including impact sensitivity, energy release performance under a certain impact, and reaction mechanism. The experimental results show that the content of Bi2O3 increased from 0% to 35.616%, the characteristic drop height of impact sensitivity (H50) of PTFE/Al/Bi2O3 reactive materials decreased first and then increased, and the minimum H50 of all types of materials in the experiment is 0.74 times that of PTFE/Al, and the particle size of Bi2O3 affects the rate of H50 change with Bi2O3 content. Besides, with the increase of Bi2O3 content, both the reaction intensity and duration first increase and then decrease, and there is optimum content of Bi2O3 maximizing the reaction degree of the PTFE/Al/Bi2O3. Furthermore, a prediction model for the impact sensitivity of PTFE-based reactive material is developed. The main reaction products include AlF3, xBi2O3·Al2O3, and Bi.

Highlights

IntroductionMetal/polytetrafluoroethylene (PTFE) as a representative, due to the high energy density and impact-induced reaction characteristics, has broad application prospects
Reactive materials, a special type of energetic material—including metal/polymer mixture, intermetallic, thermite, hydrides, and matrix material [1,2]—have been widely concerned.Metal/polytetrafluoroethylene (PTFE) as a representative, due to the high energy density and impact-induced reaction characteristics, has broad application prospects.PTFE, whose chemical formula is –(CF2 –CF2 ), is a complicated semi-crystalline material with great stability and chemical inertness at room temperature [3]
In order to study the mesoscale characteristics of PTFE/Al/Bi2 O3 composite material, scanning electron microscope (SEM, HITACHI S-4800, CamScan, Tokyo, Japan) was used

Summary

Introduction

Metal/polytetrafluoroethylene (PTFE) as a representative, due to the high energy density and impact-induced reaction characteristics, has broad application prospects. PTFE, whose chemical formula is –(CF2 –CF2 )–, is a complicated semi-crystalline material with great stability and chemical inertness at room temperature [3]. It is noteworthy that PTFE has a special property: the as-polymerized melting temperature is about 341 ◦ C, while the subsequent melting temperature is about 328 ◦ C. PTFE has at least four known phases at different pressures and temperatures. At a higher temperature (more than 380 ◦ C), because of PTFE decomposition, the volatile fluorinated gases are released, which have the ability to react with active metals releasing large amounts of heat [5]

Methods

Results

Conclusion