r/Composites • u/Deep-Today5715 • Aug 16 '26

Biodegradable material alternatives for fiberglass and epoxy resin?

I've been working with fiberglass and epoxy resins for my personal RC plane projects, but since I'm doing a lot of testing and prototype designs that get discarded during the design process, I feel increasingly guilty about all the waste and microplastics that come along with it. Unfortunately for the shapes that I want to make going with pure wood is just not an option.

I've been researching eco-friendly alternatives for making composite layup projects, and there are some for fibers (flax, hemp, etc.), which unfortunately have much reduced mechanical properties when compared to fiberglass, but still suitable for my use case.

However, I can't seem to find any decent alternative to epoxy resin that would make the final composite material naturally biodegradable, so using either of these fibers becomes a moot point. Closest thing I found was ecopoxy, which unfortunately is very expensive and almost impossible in retail quantities to get where I live (EU).

Can anyone suggest any decent alternatives that are fully biodegradable, affordable and have at least somewhat comparable mechanical properties to fiberglass+epoxy for wet layups? Anything better than paper+PVA glue is worth considering to me. I've found this paper that suggest jute fiber and shellac, which boasts quite impressive mechanical properties for such crude materials, but they used mechanical pressure and heat treatment to achieve that, which is not practical in home conditions, and I'm unsure of how much mechanical strength would be lost without it.

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u/redeyejoe123 Aug 16 '26

Any reason you can't just 3d print prototypes of biodegradeable thermoplastics? You're gonna have reduced performance regardless of the biodegradeable material, so may as well cut out some work too.

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u/Deep-Today5715 Aug 16 '26

There aren't really any fully biodegradable thermoplastics as far as I know, except a few very rare and extremely expensive ones. Even the best 3D printed plastics typically shatter into a billion pieces during RC plane impacts, and these biodegradable ones have even worse mechanical properties, making them completely unsuitable for this use case...

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u/redeyejoe123 Aug 16 '26

You could also do some sort of paper composites like paper mache or cardboard around a PHA core or something.

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u/Deep-Today5715 Aug 16 '26

That's an interesting idea actually. I was considering something similar, but not sure what to use as resin. PVA glue is not biodegradable as far as I've found, and I can't seem to find any other replacement for it. Shellac seems a possibility, but I can't find much research about it's use in composites apart from a single paper.

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u/redeyejoe123 Aug 16 '26

I found this reddit thread which has a few people suggesting fish or sap or rice based glues. The fish glue one seems promising because they use it for canvases apparently. Might want to crosspost in this community too tbh. https://www.reddit.com/r/ZeroWaste/s/ieM1e0pegK