Study on thermal decomposition characteristics of AIBN

Area of Science:

• Chemical Engineering
• Materials Science
• Thermodynamics

Background:

• Differential scanning calorimetry (DSC) often lacks the resolution to capture initial reaction stages in self-reactive materials.
• Understanding early-stage reactions is critical for safe storage and transportation, as these can escalate to runaway reactions.
• Azobisisobutyronitrile (AIBN) is a self-reactive material whose initial thermal behavior requires detailed investigation.

Purpose of the Study:

• To investigate and compare the thermal behaviors of AIBN under various conditions using calorimeters and Dewar vessels.
• To elucidate the mechanism influencing the initial reaction and self-heating behavior of AIBN.
• To understand how physical processes interact with chemical reactions during the early stages of decomposition.

Main Methods:

• Experimental analysis of AIBN's thermal behavior using differential scanning calorimetry (DSC).
• Comparative studies in various calorimeters and Dewar vessels to assess environmental influences.
• Heat accumulation storage tests in Dewar vessels to observe self-heating dynamics.

Main Results:

• Physical processes such as sublimation and melting were found to interfere with AIBN's initial chemical decomposition near its onset temperature.
• The interplay between physical effects and chemical reactions leads to varied thermal behaviors under different measurement conditions.
• Quasi-autocatalysis or thermal decomposition (TD) can occur in AIBN within the handling temperature range due to these interactions.
• Heat accumulation tests in Dewar vessels showed significantly different self-heating behaviors, attributed to the identified mechanism and vessel heat transfer capabilities.

Conclusions:

• The initial thermal decomposition of AIBN is significantly influenced by physical processes like sublimation and melting.
• The interaction between physical and chemical processes dictates the observed thermal behavior and self-heating potential of AIBN.
• Accurate assessment of self-reactive material safety requires considering both chemical reactivity and physical state changes under relevant handling conditions.