Pyrolysis Kinetics of Lignin-Based Flame Retardants Containing MOFs Structure for Epoxy Resins

Area of Science:

• Materials Science
• Polymer Chemistry
• Flame Retardancy

Background:

• Lignin, a renewable resource, is explored as a sustainable alternative for flame retardant development.
• Existing flame retardants often face environmental concerns, driving research into eco-friendly options.
• Metal-organic frameworks (MOFs) offer tunable properties for material enhancement.

Purpose of the Study:

• To synthesize a novel lignin-based expandable flame retardant incorporating melamine and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO).
• To create a composite material by integrating the flame retardant with a metal-organic framework (MOF) HKUST-1.
• To evaluate the thermal stability and activation energy of epoxy resin composites containing the developed flame retardant.

Main Methods:

• Preparation of a lignin-based expandable flame retardant (Lignin-N-DOPO) via Mannich reaction.
• In situ growth of MOF HKUST-1 onto the flame retardant to form F-lignin@HKUST-1.
• Incorporation of F-lignin@HKUST-1 into epoxy resin (EP) to create EP composites.
• Thermogravimetric analysis (TGA) to assess thermal stability.
• Determination of activation energy using Kissinger-SY, Ozawa-SY, Lee-Beck, and Gorbatchev methods.

Main Results:

• A novel F-lignin@HKUST-1 material was successfully synthesized.
• The incorporation of F-lignin@HKUST-1 significantly enhanced the thermal stability of the epoxy resin composite.
• The activation energy of the EP/15% F-lignin@HKUST-1 composite was substantially higher than that of pure lignin.

Conclusions:

• The developed F-lignin@HKUST-1 acts as an effective flame retardant, improving the thermal performance of epoxy resins.
• The increased activation energy indicates a greater energy requirement for the pyrolysis of F-lignin@HKUST-1, contributing to its flame retardant properties.
• This study highlights the significant potential of lignin-based materials, functionalized with MOFs, for advanced flame retardant applications.