All birch bark suberin/lignin composite vitrimer elastomer.

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Materials

Background:

• Birch bark contains valuable components like suberin and lignin.
• Valorization of lignin residue is crucial for sustainable chemical processes.
• Vitrimer composites offer unique recyclable and reprocessable properties.

Purpose of the Study:

• To investigate the use of Klason lignin from birch bark as a filler in suberin vitrimer composites.
• To evaluate the impact of lignin incorporation on mechanical, thermal, and recyclability properties.
• To assess the potential for creating sustainable polymers from birch bark waste.

Main Methods:

• Lignin extraction using the Klason method.
• Synthesis of suberin vitrimer composites with varying lignin content (5-20%).
• Mechanical testing (elongation, stress at break), thermal analysis, and dynamic mechanical analysis to determine relaxation times.

Main Results:

• Klason lignin particles had a mean diameter of 4.5 μm and contained reactive functional groups.
• Optimal mechanical performance (30% increase in elongation and stress at break) was achieved with 10% lignin content.
• Higher lignin content (20%) led to particle aggregation and increased vitrimer relaxation time from 750 to 1800 s at 190 °C.

Conclusions:

• Klason lignin from birch bark can be effectively utilized as a filler in suberin vitrimer composites.
• Incorporating lignin enhances mechanical properties and offers a pathway for sustainable polymer synthesis.
• The approach demonstrates the potential for valorizing birch bark waste into high-performance materials.