Phase Organization and Circularity in PLLA/Vitrimer Semi-interpenetrating Polymer Networks

Area of Science:

• Polymer Science and Engineering
• Materials Science
• Sustainable Polymers

Background:

• Development of advanced polymer networks with tunable properties is crucial for material innovation.
• Biobased polymers and covalent adaptable networks (CANs) offer sustainable alternatives with unique functionalities.
• Semi-interpenetrating polymer networks (semi-IPNs) combine properties of distinct polymer phases.

Purpose of the Study:

• To investigate the properties of semi-IPNs formed from a biobased vitrimeric CAN (DOM-MVL) and polylactic acid (PLLA).
• To explore the impact of varying PLLA:DOM-MVL ratios on thermal behavior, crystallization, and morphology.
• To assess the mechanical reprocessing and component recoverability of the developed semi-IPNs.

Main Methods:

• Synthesis of three semi-IPNs with distinct PLLA:DOM-MVL weight ratios (80:20, 65:35, 50:50).
• Thermal analysis using differential scanning calorimetry (DSC) to determine glass transition temperatures (Tg) and crystallization behavior.
• Scanning electron microscopy (SEM) to analyze the morphology after selective PLLA removal.
• Mechanical reprocessing via hot pressing and component separation.

Main Results:

• Semi-IPNs exhibited single glass transition temperatures between pure PLLA and CAN for 80:20 and 65:35 ratios.
• The 50:50 ratio showed a broad Tg, indicating plasticization by uncured resin, and enhanced PLLA crystallization.
• CAN phase inhibited PLLA crystallization in the 65:35 ratio, while the 50:50 ratio showed enhanced crystallization.
• SEM revealed porous networks with voids corresponding to PLLA crystalline domains.
• All semi-IPNs were successfully reprocessed, and both PLLA and CAN components were recovered.

Conclusions:

• The developed semi-IPNs display tunable thermal properties and crystallization behavior based on component ratios.
• The biobased CAN effectively modifies PLLA's properties, offering potential for controlled material design.
• These semi-IPNs demonstrate excellent mechanical reprocessability and component recoverability, highlighting their sustainable potential.