Lignin Reinforcement in Polybutylene Succinate Copolymers.

Area of Science:

• Polymer Science and Engineering
• Materials Science
• Sustainable Chemistry

Background:

• Industrial lignin, a byproduct of pulping, presents an underutilized source of renewable aromatic compounds.
• Biodegradable polymers like polybutylene succinate (PBS) are sought after for sustainable material applications.
• Valorizing lignin into functional polymer composites offers a pathway to reduce waste and enhance material properties.

Purpose of the Study:

• To investigate the production and characterization of biodegradable polybutylene succinate (PBS)-lignin copolymers.
• To evaluate the impact of varying lignin content and dicumyl peroxide (DCP) crosslinking on copolymer properties.
• To determine optimal lignin concentrations for specific property enhancements in PBS-lignin composites.

Main Methods:

• Reactive extrusion was employed to blend and crosslink polybutylene succinate (PBS) with industrial lignin (0-45 wt. %).
• Mechanical testing (tensile, flexural), thermal analysis (DSC), and morphological studies (SEM) were conducted.
• Dicumyl peroxide (DCP) was used as a crosslinking/grafting agent to improve interfacial adhesion.

Main Results:

• Lignin addition decreased tensile strength but increased stiffness and thermal stability of PBS.
• DCP crosslinking significantly improved interfacial adhesion and flexural performance, especially at moderate lignin levels.
• Lignin initially enhanced crystallization temperature but hindered it at higher concentrations; SEM revealed reduced phase separation in crosslinked copolymers.

Conclusions:

• Biodegradable PBS-lignin copolymers can be successfully prepared via reactive extrusion.
• Crosslinking with DCP is crucial for mitigating poor interfacial adhesion and enhancing mechanical properties.
• An optimal lignin content (e.g., 20 wt. %) provides a balance of improved properties without significant drawbacks.