Coupled Crystallization and Melt-Rheology Regulation Enables Rapid Formation of Thermally Insulating PLA-Based Microcellular Foams

Rapid cold crystallization of poly(lactic acid) (PLA) restricts cell growth, while insufficient melt elasticity compromises cell stability. Here, acrylic elastomer (ACM) and epoxy chain extender (ADR 4468) were introduced to coordinately regulate PLA crystallization and melt rheology. Experiments and MD simulations indicate that ACM disrupts crystallizable PLA domains and limits interfacial chain diffusion, whereas ADR increases molecular weight and chain entanglement, inhibiting crystal growth while enhancing melt elasticity. The resulting P/A-R blends exhibit markedly improved toughness. After just 5 min of CO2 saturation, P/A10-R achieves an expansion ratio of 39.7, a foaming window of ∼19 °C, low thermal conductivity (34.51 mW m–1 K–1), and enhanced compressive strength. This strategy effectively integrates PLA toughening with rapid, high-expansion foaming performance.