Plant-based epoxy enables recyclable carbon fiber

Re:Plant-based epoxy enables recyclable carbon fiber by morcheeba on Saturday January 29, 2022 @11:29PM (#30134037)

I've done carbon fiber boat repair, and removal is pretty easy - lots of cutting and sanding. Applying a patch works pretty well - mechanical bonding to the roughed-up surface is pretty good, and even if the patch uses 2x the material of the original, it doesn't affect overall weight too much.

There are two major complication to repair.

First, carbon fiber items are made in a mold. Repair doesn't have access to that mold, so you've got to build your own. You can get a good approximation from casting an adjacent part, or the opposite side - otherwise you have to improvise and sand it to match. Catastrophic failure, like when the bow is broken more than a few degrees, requires an alignment jig to keep the boat straight.

Second, carbon fiber works best when it's a laminate - e.g. a carbon/foam/carbon sandwich. So most designs are tubular or involve a stackup. This is tricky if the inside layer isn't accessible. Or a high-performance inner layer is used, like delicate honeycomb aluminum. Rebuilding something that was custom-made to tight tolerances is difficult.

I'd think that a degradable epoxy would be best for recycling applications; repair has a lot of other challenges.

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Re:Plant-based epoxy enables recyclable carbon fiber by extrapickles on Sunday January 30, 2022 @02:05AM (#30134751)

You would have to design the article to be repaired. The core material would need to be dissolvable so it can be refreshed along with the epoxy.

I imagine the repair process would be something like:

  1. Place bike/boat in mold/alignment frame. 
  2. Dissolve core then epoxy.
  3. Refill and cure core.
  4. Reapply epoxy to carbon fiber.
  5. Vacuum bag the bike/boat then cure epoxy.

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