Baroplastic Effect of Aliphatic Polyester Block Copolymers for Degradation-Free Multicycle Processing of...

Area of Science:

• Polymer Science
• Materials Science
• Sustainable Chemistry

Background:

• Achieving a circular plastic economy requires advancements in sustainable plastics.
• Baroplastics are block copolymers that undergo pressure-induced order-disorder transitions, enabling low-temperature processing and reducing energy consumption.
• Current baroplastic applications are limited by structural constraints.

Purpose of the Study:

• To introduce a novel baroplasticizer, poly(ε-caprolactone-random-5-ethyleneketal ε-caprolactone)-block-poly(l-lactide) (PmCL-b-PLLA).
• To demonstrate the effectiveness of PmCL-b-PLLA in lowering the processing temperature of nonbaroplastic poly(l-lactide) (PLLA).
• To overcome structural limitations in existing baroplastics for broader applications.

Main Methods:

• Synthesis of poly(ε-caprolactone-random-5-ethyleneketal ε-caprolactone)-block-poly(l-lactide) (PmCL-b-PLLA).
• Blending PmCL-b-PLLA with nonbaroplastic poly(l-lactide) (PLLA).
• Evaluation of the effect of pressure on the blend's flow temperature and molecular weight stability.

Main Results:

• Blending PmCL-b-PLLA with PLLA reduced the flow temperature by up to 100 °C (from 160 °C to 60 °C at 50 MPa).
• Molecular weight of PLLA was preserved after repeated pressure cycles, indicating recyclability.
• The improved formability is attributed to a pressure-induced phase transition from an ordered to a disordered state.

Conclusions:

• The developed "baroplasticizer" eliminates structural constraints in baroplastics.
• This enables broader low-temperature processing applications for sustainable polymers.
• The study significantly advances sustainable polymer technologies towards a circular economy.