Ultraviolet-Shielding Recyclable Polymer Film Fabricated via Knoevenagel Condensation

Area of Science:

• Materials Science
• Polymer Chemistry
• Photochemistry

Background:

• Ultraviolet (UV) radiation poses significant risks to human health, materials, and the environment.
• UV-shielding materials are crucial for protection in various industries.
• Previous work established a method for creating recyclable thermosetting polymers via Knoevenagel condensation (KC).

Purpose of the Study:

• To fabricate an ultraviolet-shielding and recyclable film using dynamic covalent bonds.
• To enhance the properties of thermosetting polymers for improved performance and sustainability.
• To explore the potential applications of this novel material in packaging, agriculture, and automotive industries.

Main Methods:

• Developed a cross-linking agent from vanillin and 1,3,5-benzenetricarbonyl chloride.
• Synthesized the P-TFMBTC-PCL film via KC reaction between the cross-linking agent and polycaprolactone (PCL).
• Utilized cyanoacetic acid end-modified PCL, where active methylene groups react with aldehyde groups to form dynamic C═C bonds.

Main Results:

• The fabricated film, P-TFMBTC-PCL, exhibits high tensile strength (18.78 MPa) and elongation at break (959.11%).
• The dynamic C═C bonds enable reprocessability and recyclability of the thermosetting material.
• The film effectively blocks 100% of UV rays from 200 to 432 nm due to expanded conjugation.

Conclusions:

• The developed P-TFMBTC-PCL film offers a promising solution for UV protection and material sustainability.
• The dynamic covalent network design facilitates recyclability and reprocessability.
• The material's properties make it suitable for diverse applications, including packaging, agriculture, and automotive sectors.