Over the last year I’ve spent a lot of time trying to find conductive plastic that has resistance properties even close to wire. What I’ve found is currently there is nothing on the market that comes even close. Although a plastic “Described” as conducting is offered by quite a few venders the conductivity it pretty bad. If you are making an anti-static pad or a Faraday cage your OK but for most circuits it’s not practical, basically it just plastic with infused Carbon Black.
I did spend some time trying to make my own and I did get some good batches but I had a real hard time with getting consistent batches. If you interested I used Multi Walled Carbon Nanotubes and infused them is standard PLA. believe it or not nanotubes are pretty cheap now. I got mine from “CheapTubes.com“. Yes, believe it or not that’s the name of the company. I tried a bunch of combinations but my greatest success was with MWNT’s around the 30-50nm range. Basic method is to take existing 3D printing plastic and mix it with “Dichloromethane” this liquefies it and after a time just remove to stopper off your mixing bottle and the dichloromethane will evaporate leaving just the plastic infused with the nanotubes. Now all you have to do is get it back in 3D printer plastic form. To do that I just built a 3D printing extruder.
If someone comes up with a better way to do it let me know but the best I was able to get was about 200 ohms per inch, still not what I was looking for but way better then stuff available on the market now.