Tailoring Architecture and Properties of Biodegradable Aliphatic-Aromatic Copolyesters via Interfacial Polymerization

Area of Science:

• Polymer Chemistry
• Materials Science
• Biotechnology

Background:

• Aliphatic-aromatic copolyesters (AAPEs) offer a balance of thermal stability and biodegradability for packaging applications.
• Current synthesis methods for AAPEs are often slow, require harsh conditions, and use expensive catalysts.

Purpose of the Study:

• To introduce a rapid, open-air synthesis of poly(p-phenylene adipate-co-terephthalate) (PPAT) using stirred interfacial polymerization.
• To investigate the effect of solvent choice (chloroform vs. ethyl acetate) and catalyst concentration on PPAT synthesis and properties.
• To tailor the aliphaticity and structure of PPAT for enhanced enzymatic degradability and tunable thermomechanical properties.

Main Methods:

• Stirred interfacial polymerization in open air using chloroform or ethyl acetate.
• Varied phase transfer catalyst concentration to control copolymer composition and structure.
• Characterization of PPAT films, including thermal stability, mechanical properties, and enzymatic degradation using PETase.

Main Results:

• Achieved high reaction yields comparable to traditional methods, regardless of solvent.
• Demonstrated tunable aliphaticity and a shift from random to block-like copolymer structures with increased catalyst concentration.
• Synthesized PPAT films with tunable thermal stability (263-310 °C) and mechanical properties.
• Showed significantly enhanced enzymatic degradation with increased aliphaticity, achieving >50% mass loss in 400 h for films with ~60% aliphatic units.

Conclusions:

• Stirred interfacial polymerization provides an efficient and rapid route to synthesize tunable aliphatic-aromatic copolyesters.
• PPAT's enzymatic degradability by PETase is significantly enhanced by increasing aliphaticity.
• This method enables the production of biodegradable polymers with tailored structures and properties for sustainable packaging applications.