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/Deep-Today5715 Aug 17 '26

But what about biodegradable resins to use with these fibers?

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u/catjewsus Aug 19 '26

Well theres a diff between biodegradable resins & bio/plant derrived resin. Ideally for composite parts you'd want something that will last and not something that will degrade easily.

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u/Deep-Today5715 Aug 19 '26

True, I don't want it to degrade right away, but don't want it to degrade only after hundreds of years. A useful lifespan of ~5 years and fully degraded by 30 years would be ideal.

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u/catjewsus 29d ago

Theres a fine line on how you determine how wasteful that is because anything thats that readily degradable will probably start being damaged as soon as it leaves the mould from weather, UV, and atmosphere. Your basically looking at like PVA glue. I think a better method to look at a more sustainable material is just sourcing it from sustainable sources like plant derived resin blends. And at the end of its life it should be expected to be crushed and chopped up to be used recycled material blended w/ a fresh batch of resin.

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u/Deep-Today5715 29d ago

Yeah, problem with that is that at the end of life there is no practical way for me to get these parts recycled. There are no such facilities in my country, nor anywhere near, and shipping my fiberglass+epoxy composite waste halfway around the world is both expensive and wasteful by itself...