恒温失重法研究高氯酸铵的热分解

Study on Thermal Decomposition of AP by Thermostat Weight Loss

采用恒温失重法对AP颗粒的热分解失重进行研究。恒温实验表明:AP颗粒在150℃和160℃下失重较少,而170℃下AP失重率最高,达36%。研究表明:AP颗粒在150℃条件下的动力学反应模式属于固体分解过程中产物核形成和生长;在160℃条件下是固体分解过程中相界面反应以及产物核形成和生长;在170℃下主要是固体分解过程中产物核的形成和生长以及二维扩散反应,以上过程与AP的低温离解、吸附和解吸过程有关。并确定其机理函数为G(α)=[-㏑(1-α)]1/m(m=1/2),求得活化能E=26.987 kJ/mol,指前因子A=0.2187s-1。10g量级实验采用间断测重,样品实际上经历了升温-降温的温度循环,该方式破坏了AP颗粒表面固有的气体吸附平衡,造成表面气体大量逃逸,这可能是AP在170℃失重率高的主要原因。

The thermal decomposition of AP particles was studied by thermal weightlessness method in this article. It was experimentally found that the weight loss of AP particles at 170℃ was much more than that at 150℃ and 160℃, and the highest rate of AP weight loss was up to 36%. It can be concluded that the kinetics mode of the AP particles at 150℃ was the formation and growth of product nucleus in the solid decomposition process, at 160℃ was the formation and growth of product nucleus and interracial reaction in solid decomposition process, and at 170℃ was the formation and growth of product nucleus in solid decomposition process, as well as two-dimensional diffusion reaction, the above processes were related to dissociation, adsorption and desorption processes of AP at low temperature. The mechanism of function G（a） was [-ln（1-a）]1/m（m=1/2）, the activation energy E was 26.987 kJ/mol and the pre-exponential factor A was 0.218 7s-1. In fact, the sample experienced the temperature circle of heating-cooling in this test, and the equilibrium was destroyed by this mode, which caused the escaping of gas on the surface of AP, this may be the main reason for high weight loss rate of AP at 170℃.