Recycling of materials from composite boats?

[mitchgrunes]

I once asked a Dupont chemist about separating and recycling the materials in composite (e.g., epoxy or other plastic resin + fiberglass or carbon fiber, etc.) boats (specifically kayaks) - and not just using the results as bulk filler in something else, but to separate out the components, to build another similar boat.

Obviously the amount of material in a composite kayak is a lot less than the amount of material in a big windmill blade, or a typical power boat or sailcraft, so this isn't an overwhelmingly important issue. Still I was curious.

He told me it was economically impractical, because the energy cost of breaking down the materials into monomers was greater than that required to create new materials from available natural resources.

It's possible he was assuming one would break down both the resin and the fiber.

Recently there has been a lot of interest in recycling large windmill blades, by dissolving or breaking down the epoxy. Apparently, they take up a lot of landfill space, and some European countries have banned land filling them:

www.chemistryworld.com/news/recycling-wind-turbine-blades-by-breaking-them-down-into-their-constituent-chemicals/4017385.article

Can wind turbine blades be recycled? | What happens to old wind turbine blades? | National Grid Group https://www.nationalgrid.com/stories/energy-explained/can-wind-turbine-blades-be-recycled

Was the chemist technically correct - that creating a reagent that can dissolve or break down epoxy, or raising the temperature to a point where a catalyst can break it down, takes more energy than needed to recreate the entire boat from raw materials?

Obviously, there are other issues - e.g., some of the recovered fibers will be shorter than the best available new fiber cloths, so a new boat made from recovered fiber will probably be less strong / weight than the original.

 

[ondarvr]

It has been tried for many decades, without government funding it isn't profitable enough for great success yet. Regulations and other considerations may require it in the future though.

 

[alan craig]

I don't know about reusing the chemicals from yachts or turbine blades but I've seen a yacht burnt on a beach; there was nothing left except some soot and all the glass fibres. So a good way to recycle them would probably be to burn them in a CHP (combined heat and power) station to produce electricity, and heat for housing or industrial processes. It would reduce the amount of fossil fuel needed to do the same job. Where I live most of our combustible domestic waste is burnt this way.

 

[Skyak]

My experience on the topic is that there are 7B people in the world and 100% of them are willing to demand that everything be recycled, 10% are willing to even study the topics required (even though such study is 10X more useful to a career), 0.00001% have studied enough to calculate what it will actually take, and the results are unattractive to say the least. Beyond the chemical energy hump to get over there is the slow process, the environmental and safety problems of the chemicals, contamination, the scale it would take to process anything significant, and the ridiculous cost of finance for something with no return -developed world is too fickle where what one administration mandates the next overturns. With one penstroke this recycling site turns from state of the art recycling to environmental "superfund" cleanup liability.
The best plan (or attempt) I have seen was by Arkema to design an epoxy to be reclaimed. They made a mini transat 6.5 out of their materials years ago and I hoped to hear the result of recycling that boat but have heard nothing. To my knowledge most material manufacturers have some "green" product you can pay more for. None have demonstrated even one cycle.
As big as they are, pleasure boats are a tiny fraction of plastic waste -and the most difficult technically. When governments deal with single use plastic we better have a viable plan.

Incineration is something the industry should be studying. That boat burned on the beach likely created enough toxic damage to cost a lifetimes wages to remediate if the government looked at it. On the other hand, if the government took just one modern coal burning powerplant (modern with scrubbers) and converted it to process composites to the same standards I think it would likely be the best solution anyone can offer.

I have been questioning a Dupont executive with a ChemE PHD and MBA for decades. He is now retired so maybe there is new hope for progress.

My personal development plan is thermoplastic composites, separable by temperature.

 

[Dave G 9N]

It is hard to find any recent news about Arkema 3. The resin was not an epoxy, but an acrylic. The advantage of acrylics for recycling is that they are thermoplastics so they can potentially be ground up and melted for reprocessing. Any composite will have a high fiber content and will be difficult to reprocess. They do say that the monomer can be recovered by thermolysis, which would produce a more versatile material. No word about the recovery rate though.

The big advantage that I see with this resin is that it may allow people who are allergic to epoxy to make frp boats. The datasheet mentions hand layup for repair, but that sounds promising for hand layup in general. The properties look good. The acrylic adhesives and possibly resin as well may bond better than epoxy to a wide range of resins for repairs.

The Composite parts made out of Elium® resin can be recycled after End-of-life in two different
ways. The first one would involve grinding and compounding to use as chopped fiber compounding
resin and the second would be a thermolysis process which allows the recovery of fibers and the
monomers by depolymerisation.

Epoxy is a thermosetting resin, and one of the features of it is chemical resistance. Thermosets are a network of crosslinked chains that tend to char before they melt and dissolving them is nearly impossible. The best I have done is to heat for a long time in very hot mixtures of DMSO and NMP, which swells epoxy, but does not dissolve it. It gets soft and crumbly, but does not dissolve. The goal was to remove epoxy potting without affecting the polyimide wire insulation, so dissolution was not important.

 

[Howlandwoodworks]

Boathenge,
Not recycling but repurposing.
Appeared out of nowhere one night along the bank of the Mighty MO.

 

[mitchgrunes]

Boathenge,
Not recycling but repurposing.
Appeared out of nowhere one night along the bank of the Mighty MO.
View attachment 193234

This is clearly a natural formation.

 

[DogCavalry]

That's often the problem with recycling. It causes more environmental damage to do it than not doing it does.

 

[fallguy]

It is a challenge to recycle even clean streams. My corecell offcuts were all cutdown to 1" strips if they were 4" long or more.

I then placed the materials in tubs where it remains today.

I used a bunch of the offcuts for cabinet shelving, but I'm at the end of the project. Almost no need for the stuff unless I build the foam dinghy I want to build.

They go together with plastic staples. The stapler saved tons of money on reusing other offcuts. We originally made 4",3",2",1" offcut strips.

Other pieces of core that were not suitable for strips could have been ground for core to be made into putties, but you need some sort of hammermill or grinder to do the work and I had none.

An electric planer sort of works, but not worth the risk of hand injury to reclaim a 1/2" square piece of core 20" long.

 

[TeddyDiver]

Repurposing when it's viable. In Northern Norway old wood boats have been used as sheep shelters upside down. A plastic one could hold longer.. How about as a hut/dwelling?

 

[Howlandwoodworks]

The Mayflower was made in to a barn.
The old river paddle wheeler sometimes would have their Cabins, decks and engines removed and set on top a new hull after a hard grounding, if the boiler didn't blow.

 

[wet feet]

Repurposing when it's viable. In Northern Norway old wood boats have been used as sheep shelters upside down. A plastic one could hold longer.. How about as a hut/dwelling?

If you ever come across the series of books written by Charles Dickens in the nineteenth century you will find that he had the same idea and had the Pegotty family living in an upturned boat in the dunes.

 

[comfisherman]

Going from aluminum and steel to playing with frp boat building the surprise was the shocking amount of plastic consumables and the shear volume of plastic that went to the landfill. Kinda like modern groceries, takes near 3 layers of plastic for one little item.

 

[Dave G 9N]

If you ever come across the series of books written by Charles Dickens in the nineteenth century you will find that he had the same idea and had the Pegotty family living in an upturned boat in the dunes.

Probably more comfortable than the 22 members of Shackelton's crew who spent the winter on Elephant Island waiting for 4 months under 2 lifeboats for a ride home.

 

[comfisherman]

Yikes. I hope to never be that cold.
Spent January on a glass boat that had an un insulated v berth area. That was cold enough....