A Little Update on Natural fiber and Plant Resin Composites
- Ned Patton
- 2 hours ago
- 9 min read
This post, again, is at least loosely based on what I wrote in my new book, “Sustainable Composite Materials: A Roadmap to a Circular Economy” released on April 6 by McFarland, my publisher. And, if you are going to SAMPE in Seattle next week, I will be doing a book signing there on Tuesday April 28 in the SAMPE Spotlight Theater.
What I plan to talk about in this post is the business of entirely plant-based composite materials. I bring this up because I did talk about it in my latest book, and from where this long time composite materials user sits, it is fairly obvious that this is the direction that the composite materials industry is heading. And, of course, this is the long horizon view, and it is only my perspective, but from what I have been reading about for the last year or so this is what is on the horizon and nearly all of the major players in this business are paying attention.
Already the automotive industry is adopting flax, jute and hemp fiber composites for interior door panels and trunk liners. The recreational marine industry is also adopting these composites for pleasure boat interiors because the fibers have the strength and stiffness of traditional glass fibers and weigh about half as much as glass. And in the regions of the world where bamboo grows naturally there are several suppliers of bamboo composites that have products for the construction industry, recreational marine, residential decking, furniture, and all manner of other long life consumer goods that were traditionally fiberglass or other plastics, or even wood.
On the resin side, there are a number of companies that make plant-based resins like Bitrez Ltd.’s family of bio-resins that was launched at JEC World in May of 2020 (pictured above), Lingrove’s Ekoa that is flax fiber composite with a plant-based resin for use as a lightweight wood alternative, Plantics Biomaterials which is a Dutch company that produces a 100% bio-based thermosetting resin from plant waste that is commonly used with hemp fibers for indoor furniture to replace wood, Applied Bioplastics that makes a plant-based resin that is usually paired with jute fibers and used in the construction and automotive industries, two companies I mentioned last week – Scott Bader with Crestapol™ and Entropy Resins which was recently acquired by West System primarily for their EnviroPoxy plant based epoxy, and a host of others all with different formulations and going after different sectors of the composites industry.
So there is a lot going on in this space now and there are a number of commercial products on the market that have been adopted by different industries for a variety of reasons. One of those reasons is that natural fibers are generally lighter weight than other composite fibers for the same strength and stiffness, primarily because they are largely cellulose. And they also are less expensive than the fibers that they replace as well. As for the plant-based resins, there are similar motivations in that they are inherently recyclable, can be less expensive than traditional petroleum based resins, and are entirely renewable since they come from plants.
The companies mentioned above are largely fairly new and just now starting to scale up production of their fully plant based renewable composite materials. Bcomp of Switzerland is arguably in the lead here with their flax-based natural composites. I have written about them previously and shown a picture of the body of the demonstrator Porsche 928 race car that they made. These folks are addressing some needs in lightweight, aesthetically pleasing parts of the automotive, aerospace, and recreational marine industries where they are replacing glass composites with their flax-based bio-composites. Lingrove in the US is doing much the same thing and also using flax fiber and plant-based resins addressing the US sector of those three markets.
Another company in Bremen Germany, Circular Structures GmBH, has been in the business of making natural fiber – mostly flax – composite materials and structures for the recreational marine and camping industries. Their Greenboats division started with a 27 foot daysailer (pictured above) and has since expanded their line to include an outboard runabout, a skiff, a kayak, and even a flax fiber Beneteau sailboat. And they are now expanding their line into a number of other areas in the recreational and commercial marine and offshore business. In addition to Greenboats, they make a camper shell to put on the back of an offroad truck as well as providing a line of flax fiber fabrics, roving, prepregs, and laminated panels for use in any number of applications. Predominantly Circular Structures uses inherently recyclable and plant-based resins for their prepregs and laminates, so they sell entirely plant-based composites.
In the hemp fiber business, BioComposites Group, a North Carolina startup uses hemp fiber and natural resins for automotive interiors. They also have a geotextile product made using hemp fiber that is used for erosion and weed control as well as retaining water and thereby promoting vegetative growth. While this isn’t a composite material it is interesting that a composite material supplier is also in the biodegradable geotextile business.
With all of this going on and all of these companies that have natural fibers and plant-based resin systems, where is the future in plant-based composites. One answer is to look for the largest source of raw materials to use to make composite fibers and resins – the string and glue that mother nature makes, namely cellulose fiber and lignin glue. These are the most abundant organic molecules on the planet and are what makes up the structure of every plant.
We have talked a bit so far about the natural fibers that are in use in a number of applications, all of which are mostly cellulose with enough lignin to hold the fibers together. In addition to this, there has been quite a bit of work done to use the chemical nature of cellulose and lignin both to make something more akin to the carbon fiber / epoxy advanced composites that are in use today.
There are folks that are working on using these two compounds to make both carbon fiber and epoxy resins. Cellulose is a very long chain polysaccharide (sugar-like) molecule which makes it somewhat more difficult to turn into carbon fiber because the saccharide grouping that makes up the structure of the fiber is a benzene-like structure that has an oxygen atom replacing one of the carbons. This makes it somewhat more difficult to make into the long chain of benzene rings that make up carbon fiber.
There are researchers that have tackled this problem and there are also a couple of startups that are actually producing carbon fiber using cellulose, sometimes as hemicellulose which is sort of a hybrid between a saccharide and an aromatic, but still mostly cellulose. A couple of new names in this business are Stora Enso and Cordenka, along with one of the largest chemical companies in the world, Syensqo. There are a few others, mostly in Europe, that are also in this business. And it appears that all of these companies and the research organizations are doing rather well and starting to enter into some parts of the carbon fiber marketplace.
Lignin on the other hand is more of an aromatic molecule (benzene rings stuck together with some other stuff) which makes it somewhat easier to turn into a carbon fiber. The problem with lignin, however, is that it is not one compound, it is a family of branched aromatics that are different plant to plant and are even different in each plant. Essentially the lignin molecules are purpose built for each application in each plant. What this means is that just the overall variability in the chemistry of lignin poses difficulties in producing a chemically pure product like acrylonitrile.
As it turns out that coming up with acrylonitrile is not really required with lignin, since purified lignin, even though it is many different compounds, can be spun into a fiber and carburized into a carbon fiber. Apparently the resulting fiber is an approximate equivalent of Toray’s T300. This is Toray’s basic industrial carbon fiber, and they sell more of this stuff than any other grade of carbon fiber. And this fiber can be made for about half the cost of T300 because the precursor, being a waste product, is basically free. While that doesn’t mean necessarily that the lignin is free, but the forest products or agricultural waste from which it can be extracted is free.
The bottom line here is that it appears that plant-based composites are not only here but are here to stay. And once the process of producing carbon fiber and epoxy resins from forest products and agricultural waste is perfected, just because they are roughly half the cost of their petroleum counterparts, it is my contention that within the next decade or two we won’t be using petroleum to make advanced composites.
This is something of a warning for the companies that use the petroleum today to make carbon fiber and epoxy resins that if you don’t transform your business to using plant-based products, you may not have a long term future. That is in fact the reason I wrote “Sustainable Composite Materials” in the first place – to provide a roadmap to the industry for how to manage this transition while staying in business.
Which leads me to next week’s post where I am going to talk about that roadmap and what it means. So, I’m going to stop here for this week’s post. As always, I hope everyone that reads these posts enjoys them as much as I enjoy writing them. And I hope people who are interested find something they can use in their lives or at least some ideas that they might be able to put into practice. At least I hope that these make people think a bit about sustainability and some of the major issues looming before us.
I am in Seattle attending the SAMPE Conference as I post this. The conference this years is great as usual, and there is representation both on the exhibits floor and in the technical talks and presentations from every corner of the industry. I gave a talk in the SAMPE Spotlight Theater about my newest book and why I wrote it. That talk was well received and I gathered a few more contacts that I will add to my list of people that receive these posts.
As usual, I will post it first on my updated website – www.nedpatton.com – and then on LinkedIn. And if anyone wants to provide comments to this, I welcome them with open arms. Comments, criticisms, etc. are all quite welcome. I really do want to engage in a conversation with all of you about composites because we can learn so much from each other as long as we share our own perspectives. And that is especially true of the companies and research institutions that I mention in these posts. The more we communicate the message the better we will be able to effect the changes in the industry that are needed.
My second book, which was released on April 6, is a roadmap to a circular and sustainable business model for the industry which I hope that at least at some level the industry will follow. Only time will tell. Maybe it will get noticed – as always that is just a crap shoot. I have several of them in stock to sell on my website if anyone is interested, and it is available on Amazon, Barnes and Noble on line, other online bookstores, and of course directly from my publisher, McFarland. Amazon in fact has it discounted to $31 so that's what I'm selling it for on my website as well.
As usual, I’ve included a photo of the cover at the end of this post. Let me know whether or not you like the cover. Hopefully people will like it enough and will be interested enough in composites sustainability that they will buy it. And of course I hope that they read it and get engaged. We need all the help we can get.
Last but not least, I still need to plug my first book. “The String and Glue of our World” pretty much covers the watershed in composites, starting with a brief history of composites, then introducing the Periodic Table and why Carbon is such an important and interesting element. The book was published and made available August of 2023 and is available both on Amazon and from McFarland Books – my publisher. However, the best place to get one is to go to my website and buy one. I will send you a signed copy for the same price you would get charged on Amazon for an unsigned one, except that I have to charge for shipping. Anyway, here’s the link to get your signed copy: https://www.nedpatton.com/product-page/the-string-and-glue-of-our-world-signed-copy. And as usual, here are pictures of the covers of both books.
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