In Situ Constructing Highly Aligned Ribbon-like PHBV Lamellae in PBAT: Towards Strong, Ductile and High-Barrier...

Area of Science:

• Materials Science
• Polymer Science
• Polymer Engineering

Background:

• Poly(butylene adipate-co-terephthalate) (PBAT) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) are biodegradable polymers with distinct properties.
• Improving the mechanical and barrier performance of PBAT/PHBV blends is crucial for their wider application.
• Existing methods often struggle to achieve optimal interfacial adhesion and morphology control in PBAT/PHBV blends.

Purpose of the Study:

• To develop a facile method for fabricating PBAT/PHBV films with superior mechanical and barrier properties.
• To investigate the role of a reactive compatibilizer (RC) in controlling the morphology and enhancing the properties of PBAT/PHBV blends.
• To optimize the formation of ribbon-like lamellae during blow-molding for enhanced material performance.

Main Methods:

• Melt blending of PBAT and PHBV with a styrene-methyl methacrylate-glycidyl methacrylate copolymer as a reactive compatibilizer (RC).
• Utilizing blow-molding with biaxial stretching and rapid cooling to induce the transformation of PHBV structures into ribbon-like lamellae.
• Characterizing the morphology, mechanical properties (yield strength, elastic modulus), and barrier properties (water vapor and oxygen transmission rates) of the fabricated films.

Main Results:

• In situ formation of well-aligned, ribbon-like PHBV lamellae within the PBAT matrix was achieved, particularly at PHBV content ≤30 wt.%.
• The addition of RC effectively reduced PHBV domain size, improved interfacial adhesion, and increased lamellar number density.
• Significant enhancements were observed: yield strength increased by >600%, elastic modulus by >200%, and water vapor/oxygen transmission rates decreased by ~81% and ~85%, respectively.

Conclusions:

• The developed method provides a facile approach to fabricate high-performance PBAT/PHBV films with enhanced mechanical and barrier properties.
• The in situ formation of ribbon-like lamellae, controlled by RC and blow-molding conditions, is key to achieving these property improvements.
• The study demonstrates the potential of this approach for creating advanced biodegradable polymer films for various applications.