Time-temperature-transformation-layering diagrams: a design tool for lightweight multi-layered, single-material...

Area of Science:

• Materials Science
• Polymer Engineering
• Sustainable Manufacturing

Background:

• Multi-material structures are often required for optimal performance but hinder recycling efforts.
• Reducing material diversity is a key strategy for enhancing recyclability in product design.

Purpose of the Study:

• To demonstrate a method for creating multilayered structures from a single semi-crystalline polymer.
• To reconcile the demands of high performance with the principles of sustainable design and recyclability.

Main Methods:

• Engineering coupled mass and heat transport during polymer processing.
• Identifying a specific processing window where characteristic times for foaming agent transport, heat transport, and polymer crystallization are comparable.
• Utilizing a time-temperature-transformation-layering diagram to control the layering process.

Main Results:

• Successfully created multilayered structures using poly(lactic acid) and poly(ethylene terephthalate) with CO2 as a foaming agent.
• Validated the ability to achieve distinct layers based on crystallinity and foaming within a single material.
• Demonstrated that high performance and sustainability are achievable simultaneously.

Conclusions:

• The developed processing strategy enables the creation of advanced single-material multilayered structures.
• This approach offers a pathway to improve the recyclability of high-performance polymer products.
• The methodology has broad applicability to other materials and processes requiring layered structures.