Arduino is at work to make bio-based PCBs

From the actual paper: "The resulting yield of PCB production was around 50%. Signal analysis was successful with analogue data acquisition (voltage) and low-frequency (4 kHz) tests, indistinguishable from sample FR4 boards. Eventually, the samples were subjected to highly accelerated stress test (HAST). HAST tests revealed limitations compared to traditional FR4 printed circuit materials. After six cycles, the weight loss was around 30% in the case of PLA/Flax, and as three-point bending tests showed, the possible ultimate strength (25 MPa at a flexural state) was reduced by 80%."[1]

This sort of problem has come up many times with attempts to put some biological filler material into a composite. Most biological materials absorb and release water, and change size and weight as they do. This causes trouble for anything exposed to humidity changes. The classic "hemp/soybean car" ran into this problem.[2] In 1941, plastics were more expensive, and there were attempts to find some cheap material to use as filler. That never got beyond a prototype. Modern attempts at bio-composites seem to hit the same problem.[3]

This might have potential for cheap disposable toys, where expected lifetime is in months and disposal as ordinary trash is desirable.

[1] https://iopscience.iop.org/article/10.1088/1361-6528/ad66d3

[2] https://en.wikipedia.org/wiki/Soybean_car

[3] https://en.wikipedia.org/wiki/Biocomposite

and built to last in every sense.

Strong doubt. All this is just greenwashing planned obsolescence to make things self-destruct more quickly, so they can keep selling you more.

I wonder how it compares to FR-2, an older paper-based PCB substrate. These new bio-based PCBs seem to have some characteristics closer to that than to regular FR-4.