Multifunctional Performance Lignin-Crosslinked-PVA Composite Film Based on a Dual Crosslinking Network

Area of Science:

• Materials Science
• Polymer Chemistry
• Biocomposite Engineering

Background:

• Poly vinyl alcohol (PVA) and lignin biocomposites often suffer from poor interfacial compatibility, limiting their performance.
• Existing methods struggle to effectively integrate these materials, hindering the development of high-performance biocomposites.

Purpose of the Study:

• To develop a synchronized crosslinking strategy for seamless integration of lignin and PVA.
• To enhance the interfacial compatibility, mechanical properties, and functional characteristics of PVA-lignin biocomposites.

Main Methods:

• Introduction of vinyl groups into both lignin and PVA molecular chains.
• Formation of dense covalent bonds via reactions between unsaturated carbon-carbon double bonds.
• Creation of a dual network structure combining covalent crosslinking and hydrogen bonding.

Main Results:

• Achieved significantly enhanced interfacial compatibility between lignin and PVA.
• Demonstrated a substantial increase in film toughness with an elongation at break up to 4300%.
• Exhibited excellent UV-blocking (>90%), strong antioxidant activity (82% DPPH scavenging), enhanced hydrophobicity (100° contact angle), and improved thermal stability.

Conclusions:

• The synchronized crosslinking approach effectively integrates modified lignin into a robust PVA matrix.
• This method provides a versatile route for fabricating high-value lignin-based composite materials with superior properties.
• Homogeneous dispersion and efficient stress transfer within the dual network contribute to the dramatic property enhancements.