Researchers have found a way to make flexible 3D material far more durable.
TPU is a type of elastomer, and it is one of the most common 3D print materials. It’s used to print flexible objects, such as hinges, grips and gaskets. The problem is that it’s pretty easy to tear the TPU, and for objects with repeated flexing, like hinges, the material deteriorates eventually.
Researchers at EPFL made an interesting discovery by blending rubber-like particles with a softer elastomer material. The composite was called a double network granular elastomer, or “DNGE”.
They found that the DNGE material, when printed, exhibited some very different characteristics:
- 15X fracture toughness
- 3X fatigue resistance
Mechanical strain is shared between the two networks, which provides better performance. EPFL explains:
“When stretched, the materials redistribute mechanical stress from the stiff microparticles into the softer regions between them. There, strain energy can be repeatedly dissipated through the sliding and rearrangement of polymer chains, rather than through the irreversible breakage of polymer bonds, limiting permanent damage.”
And:
“The DNGEs’ granular structure also changes how cracks move through them. Rather than following a straight path, cracks prefer to travel through the softer regions between the elastomer microparticles, producing a winding route that slows their growth and delays failure.”
The discovery appears to be accidental, as they had intended on designing the material for improved processing. But along the way they realized they had created a far more durable flexible material.
There’s also a sustainability angle: the researchers used biodegradable elastomers that were derived from recycled materials.
This leads to an interesting question: could DNGE become a commonly available 3D print material? It sounds like it is fairly easy to produce, and provides outstanding performance.
If such materials could be made in predictable degrees of hardness at reasonable pricing, I expect they could become quite popular in the FFF world.
Via EPFL
