ORNL develops sustainable plant-based 3D printing material with superior layer adhesion strength

The Oak Ridge National Laboratory, also known as ORNL, is consistently on the cutting edge of additive manufacturing innovation. In a recent initiative, ORNL researchers have developed plant-based 3D printing materials which not only make use of biofuel byproducts but also demonstrate improved inter-layer adhesion for printed parts.

The material in question is made from a combination of rubber, carbon fiber, acrylonitrile butadiene styrene (ABS) and lignin, which is the key ingredient. Lignin, a key structural material in plant tissues, is also a byproduct of biofuel production processes. In other words, finding a use for the organic polymer could be beneficial to all involved as it would cut back on biofuel byproduct waste, could offer biorefineries an addition form of income and be used to produce better 3D printing plastics.

In terms of printability, the ORNL team says its plant-based material has excellent properties and performance: as lignin naturally adds sturdiness to plant cell walls, the material offers a similar function in the 3D printing material. In fact, when printed, the material has demonstrated 100% improved weld strength between the layers of ABS.

“To achieve this, we are building on our experience with lignin during the last five years,” commented ORNL’s Amit Naskar. “We will continue fine tuning the material’s composition to make it even stronger.”

A study recently published in the journal Applied Materials Today delves into the material’s development further and explains how using melt-stable lignin (sourced from biorefineries) in combination with ABS, acrylonitrile-butadiene rubber and carbon fibers resulted in a highly printable material with “100% improved inter-layer adhesion strength.”


For example, adding 10 wt.% nitrile rubber helped to toughen the ABS and lignin blend significantly, while adding 10 wt.% of carbon fibers helped to enhance the materials performance and decreased the degree of chemical crosslinking. In terms of lignin content, the researchers say they successfully 3D printed plastic composites with 40 wt.% of lignin.

Down the line, ORNL’s innovative lignin-based 3D printing material could provide a model for producing more plant-based thermoplastics for additive manufacturing and reduce the need for unsustainable petroleum-based thermoplastics.

Kai Parthy’s new GROWLAY filament can 3D print breeding grounds for seeds and spores

If you’re nostalgic for the days of Chia Pets, you might be very excited to learn about filament pioneer Kai Parthy’s latest 3D printing material. Called GROWLAY, the new filament can be printed into various structures and then functions as a breeding ground. Unlike the famous 1980s toy, which could sprout chia sprouts and grass, GROWLAY objects can be used to breed  a wide number of things including grass, moss, fungus, mildew, lichen, mycelium, phama-cultures and mother cells.

Kai Parthy, founder of German-based filament developer Lay Filaments, never disappoints with the borderline experimental materials he creates. He is perhaps best known as the inventor of wood filament, but he has also created a range of innovative 3D printing materials including SOLAY, a rubber-like material; POROLAY, a series of patent-pending porous and felt-like materials; LAYCERAMIC and LAYBRICK; and REFLECT-o-LAY, a glowing, reflective material.

Left to right: 3D printed GROWLAY brown cup, mold growth and slow-growing lichen

GROWLAY, the latest addition to his portfolio of additive manufacturing filaments, is one of the most intriguing yet, as it enables users to use printed objects as a sort of base for growing seeds or spores.

This is achieved by the material’s microcapillary properties, which function as tiny cavities that can absorb and store water as well as liquid nutrients or fertilizer. Parthy writes that because the capillary action runs throughout the printed object, it is well suited for storing liquids which can help grow organic materials.

For example, mold can begin to grow through the open-cell capillaries to form a mycelium, grass seeds can “get caught” and grow in the material, spores can germinate in the material’s small cavities, roots can attach themselves to the printed structure and lichens, which normally grow on stone walls or trees, can even begin to form.

Aside from being conducive to growing plants or fungi, GROWLAY boasts a few other properties which are worth mentioning. For one, it can be sterilized with gases or wet treatments (though not thermal treatments), making it suitable for food use or research purposes. It can also be dyed post-printing with safe materials like food colouring, which can be useful for colour differentiation in research.

Parthy has developed two versions of the material: GROWLAY white and GROWLAY brown. The white version is described by the materials developer as a fully compostable, “experimental filament” with open capillaries, well suited for experienced users.

GROWLAY brown, for its part, contains wood particles which act as “food” for promoting the growth of organic cells in the material. The brown version is not compostable and offers some more reliable print properties, including higher tensile strength, better temperature stability and more rigidity. Parthy says it can be printed “as easily as Laywood” and can be used by any level of user.

The innovative indoor farming filament is currently still patent pending.