Confinement Effect in Multilayer Films Made from Semicrystalline and Bio-Based Polyamide and Polylactic Acid

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Developing high-performance, eco-friendly packaging materials is crucial.
• Traditional multilayer films face limitations in barrier properties and sustainability.
• Nanolayering offers a novel approach to engineer material properties at the nanoscale.

Purpose of the Study:

• To create advanced bio-based multilayer films using nanolayer coextrusion.
• To investigate the impact of nanolayering on polyamide (PA11)/polylactic acid (PLA) films.
• To correlate microstructure, thermal, mechanical, and barrier properties.

Main Methods:

• Utilized nanolayer coextrusion to produce PA11/PLA films with varying layer numbers (3 to 2049).
• Investigated the stratified structure and measured layer thicknesses.
• Analyzed barrier properties (gas and water permeability), thermal stability, and mechanical behavior.

Main Results:

• Achieved nanostratified films with tunable layer thicknesses down to the nanometer scale.
• Observed increased PLA crystallinity (4% to 16%) and enhanced thermal stability.
• Demonstrated significant improvements in gas barrier properties (e.g., 66% BIF for N2) and water barrier properties (up to 11x reduction in permeability).
• Correlated barrier performance to microstructural rearrangements and polymer confinement effects.

Conclusions:

• Nanolayer coextrusion is an effective method for creating high-barrier bio-based films.
• Confinement effects in nanolayers significantly enhance gas and water barrier properties.
• The study highlights the potential of PA11/PLA nanolayered films as sustainable alternatives with superior performance.