Microcellular extrusion foaming of poly(lactide)/poly(butylene adipate-co-terephthalate) blends

Area of Science:

• Materials Science
• Polymer Science
• Biomaterials Engineering

Background:

• Biodegradable polymers like PLA and PBAT are crucial for sustainable materials.
• Microcellular foaming enhances polymer properties for diverse applications.
• Understanding blend compatibilization and nucleating agent effects is key for optimizing foam structures.

Purpose of the Study:

• To investigate the impact of talc and compatibilization on the microcellular foaming of PLA/PBAT blends.
• To analyze the effects of processing parameters on foam morphology, volume expansion, and crystallinity.
• To compare a commercial compatibilized blend (Ecovio) with a non-compatibilized blend.

Main Methods:

• Microcellular extrusion foaming using CO2 as a blowing agent.
• Preparation of various PLA/PBAT formulations, including pure PLA, talc-modified, compatibilized (Ecovio), and non-compatibilized blends.
• Analysis of foaming properties (cell morphology, VER, OCC, crystallinity) using DSC and microscopy.

Main Results:

• Talc addition generally decreased cell size and VER while increasing cell density and crystallinity.
• Compatibilization merged PLA and PBAT melting peaks, reduced cell size and VER, and increased cell density.
• Die temperature showed varying effects on open cell content and no significant effect on crystallinity, with cell size and VER remaining stable for most formulations.

Conclusions:

• Talc acts as an effective nucleating agent, refining foam structure and enhancing crystallinity.
• Compatibilization improves blend miscibility and positively influences foam characteristics.
• Optimizing talc content, compatibilization, and processing temperature is crucial for tailoring PLA/PBAT foams for specific applications.