Environmentally friendly upcycling of PHA-based copolymers.

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Chemistry

Background:

• Bioplastics offer a sustainable alternative to conventional plastics but require efficient recycling and valorization methods.
• Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) is a biodegradable polymer with potential for circular applications.
• Developing methods for recycling and functionalizing PHBH is crucial for its widespread adoption.

Purpose of the Study:

• To develop a solventless method for the partial chemical decomposition and branching of PHBH using renewable reagents.
• To utilize the resulting branched oligomers as additives in creating porous PHBH films via Non-Solvent Induced Phase Separation (NIPS).
• To evaluate the functional properties of these porous films, including dye retention, palladium chloride adsorption, catalytic activity, and enzymatic degradability.

Main Methods:

• Solventless partial chemical decomposition and branching of PHBH using pentaerythritol and zinc stearate.
• Characterization of oligomers using 1H NMR, IR, and DSC.
• Fabrication of porous PHBH films using Non-Solvent Induced Phase Separation (NIPS) with Cyrene®.
• Assessment of dye and palladium chloride retention capacity.
• Evaluation of catalytic activity of supported palladium clusters.
• Enzymatic hydrolysis studies using Humicola insolens Cutinase (HiC).

Main Results:

• Branched PHBH oligomers were successfully synthesized, with molecular weight and glass transition temperature tunable by polyalcohol content.
• Porous PHBH films incorporating these oligomers demonstrated effective retention of a model dye.
• The films facilitated the formation of catalytically active palladium clusters after adsorbing palladium chloride.
• Enzymatic hydrolysis of the films was confirmed, indicating biodegradability.

Conclusions:

• A sustainable, solventless method for PHBH recycling and functionalization was established.
• The developed porous PHBH films show promise for applications in dye sequestration, catalysis, and biodegradable materials.
• This work contributes to the circular economy of bioplastics by valorizing recycled materials.