Amorphous Polylactide Bead Foam-Effect of Talc and Chain Extension on Foaming Behavior and Compression Properties

Polylactide (PLA) bead foams show a high potential regarding their applicability in packaging or consumer products. Concerning the comparable properties of PLA to Polystyrene (PS) and the good CO2 footprint it represents a potential alternative to petroleum-based polymer foams. However, foaming of PLA is challenging, due to its low melt strength, therefore chemical modifiers are often used. Concerning the bead foam technology regarding PLA, the available literature is limited so far. Within this study, the bead foaming behavior of neat and modified amorphous PLA was investigated. The material was modified by talc and an epoxy-based chain extender. These compounds have been investigated regarding their sorption behavior in CO2 atmosphere and their foaming behavior. Foaming was conducted by using the batch foaming method based on a rapid temperature increase after saturation with CO2. In order to achieve welded bead foams, a one-step processing for foaming and welding has been established. Finally, the compression properties of the PLA bead foams have been investigated. Densities below 50 kg/m3 for single bead foams and 80 kg/m3 for molded foams were achieved, respectively.

Automated summary

The study investigates the foaming behavior and compression properties of bead PLA foam materials, using chemical modifiers and establishing a one-step processing method for foaming and welding.