Non-Isothermal Sublimation Kinetics of 2,4,6-Trinitrotoluene (TNT) Nanofilms

Area of Science:

• Physical Chemistry
• Materials Science
• Spectroscopy

Background:

• Sublimation kinetics of low-volatile materials are critical for applications like explosives detection.
• Isothermal methods can be time-consuming; non-isothermal methods offer a more efficient alternative.
• 2,4,6-trinitrotoluene (TNT) is a widely studied explosive material with low volatility.

Purpose of the Study:

• To measure the sublimation activation energy of 2,4,6-trinitrotoluene (TNT) continuous nanofilms in air.
• To adapt established non-isothermal kinetic models (Ozawa, Flynn⁻Wall, Kissinger) for UV-Vis absorbance spectroscopy.
• To validate the applicability of non-isothermal analysis for nanoscale sublimation kinetics.

Main Methods:

• Preparation of TNT nanofilms using spin coating deposition.
• In-situ UV-Vis absorbance spectroscopy measurements under rising temperatures and varying heating rates.
• Analysis of sublimation kinetics using Ozawa, Flynn⁻Wall, and Kissinger non-isothermal models.

Main Results:

• Non-isothermal activation energy values for TNT nanofilms were determined: Ozawa (105.9 ± 1.4 kJ mol⁻¹), Flynn⁻Wall (102.1 ± 2.7 kJ mol⁻¹), and Kissinger (105.8 ± 1.6 kJ mol⁻¹).
• These values align well with previously reported isothermal measurements for TNT nanofilms using UV-Vis spectroscopy.
• Demonstrated successful application of non-isothermal analytical techniques at the nanoscale.

Conclusions:

• Non-isothermal sublimation kinetics analysis is a viable and time-efficient approach for low-volatile materials, including explosives.
• UV-Vis absorbance spectroscopy, coupled with non-isothermal models, provides accurate sublimation kinetics data for nanoscale films.
• This methodology enhances the study of sublimation processes relevant to explosives detection and materials science.