High performance composite panels from renewable, bio-based polymers


EconCore has optimized the patented ThermHex production technology to produce honeycomb cores and sandwich panels made from bio-based plastics.

Today, the exploitation of the economic advantages of weight reduction have become essential for many industries, writes Jochen Pflug, CEO of Belgium-based EconCore. Bio-based polymer materials are still relatively expensive compared to, for example, PP alternatives and this has limited the use of these materials in structural applications. Bio-based sandwich panels can be used in, for example, re-usable packaging, furniture, automotive interiors or separation walls. By combining its cost-efficient production technology with renewable materials, EconCore is able to present a sandwich panel that has excellent mechanical properties, while still being cost competitive with traditional sheet materials. The last 6 months EconCore has optimized the production technology to produce PLA based hexagonal honeycomb cores using a continuous production process. Only moments after the core is produced skin layers are added in a second step of the continuous production process. These skins could be made from unfilled PLA material to make a mono-material panel or, in case a higher performance is required, could be replaced with consolidated flax in a PLA matrix. Poly-Lactic Acid (PLA) is a biopolymer used to make for example packaging, consumer goods and furniture and is derived from renewable resources instead of oil. A biopolymer offers more disposal options and is more environmentally friendly to manufacture than traditional petroleum-based plastics. Derived from 100% annually renewable resources such as plants, PLA generates significantly less greenhouse gas emissions over the lifetime when compared to traditional materials like PP.

Performance comparison
The table below shows indicative values for a PLA based honeycomb core and a panel made from a PLA core with PLA skins. Three-point bending measurements were done according to ASTM D790M with a span of 220 mm. The flat compression strength measurements were done according to ASTM C365 on samples with 60x60 mm size. From the table, the excellent compression strength of PLA based honeycomb core can be observed. The right column shows the performance of an actual PLA panel. To make a panel with a comparable stiffness from solid PLA, a PLA sheet thickness of a least 12 mm would have been needed.