Letters From The Earth

Thunder and lignin

By Calvin Frost | July 21, 2014

I just sent $50 to Friends of the Earth.  I don’t know how they found me but they did.  I suppose I’m on every “green” list in the world and most of the time the request for money falls on deaf ears. The messages are quickly recycled as most everything in our household.

This particular organization has a specific focus - bees - and the message is very compelling.  To be honest, I have noticed a bee decline in our gardens. I haven’t seen as many lately.  So when this appeal came, I read it and sent a check.  I didn’t realize, for example, that every three bites of food that you and I eat is pollinated by honey bees. Or, that 80% of flowering plants rely on bees for pollination for reproduction.  Bees are dying, according to Friends of the Earth, because of colony collapse disorder (CCD). Now science says that CCD is caused by pesticides, one of the most powerful being neonicotinoids, or neonics. All of this makes sense to me so I agreed to send a note to Home Depot (one of my favorite stores) and Lowe’s asking them to cease using any product that may contain neonicotinoids, like plants and seeds.  Yes, I sent the letter.

Solutions are simple if we just use our heads. It’s all about considering “the end” from “the beginning.”  Don’t put wind turbines in places where birds live and/or migrate. I really think this goes back to designing for end of life.  I’ll talk about wind energy and renewable energy in another column. Suffice it to say, whether it is buying products that have been treated with pesticides or making pressure sensitive laminate without concern for a sustainable solution for its by-product, neither helps our planet.  It just adds to stress.  And this leads me to the subject of this column, the conversion of lignocellulosic by-product from trees and grasses to polymers that are identical to petrochemical derivatives.  This is almost as exciting as IBM’s development of “Titan” and “Hydro”; more later about these two.

The amazing part of the lignin story is, why did it take industry so long?  I know why:  products that were developed years ago were developed without any concern for end of life!  Hah!

I love lignin! Do you know what it is? Bill, John, Sheila, Petri – do you remember lignin from your paper days?  Everyone in the paper world knows about lignin.  What about you petrochemical people?  Do you know what lignin is? Surely you do because you have your lignin, too.  And, to be fair, “petro people” have done a far better job with their lignin than the paper industry.  You’re way ahead but thank goodness the paper people are catching up.

Lignin is by-product generated in the pulp manufacturing process. It’s the “glue” that keeps a tree together. It is a polyaromatic material found in most living plants as an outcome of photosynthesis. For the most part a tree is made up of cellulose, fibers and lignin.  The pulp guys want the cellulose for strength (pulp).  Lignin is the by-product that was spread on fields, dumped, and during the last fifty years used for energy. But now it is also used in adhesives, sealants, thermoplastics, binders, etc.  It is also a wonderful, non-petroleum source of aromatic materials including phenols.  The petro guys figured it out before the cellulose guys. Making gasoline from oil creates “by-product.” Since we were making so much gasoline, the petrol industry had to create alternatives to landfilling.  Mobil, Exxon, BP, Texaco, and Shell began to formulate polymers, resins, and in the 20s and 30s they created “plastics” with lots of derivatives such as PE, PP, PET, etc.  Voila, they solved their problem.

In the meantime, the paper guys continued to burn lignin for energy until quite recently.  If we consider just phenolics, today most commercial phenolics still come from petroleum.  However, in several development projects, lignin is being used as an alternative that is renewable, sustainable, and competitive with petrochemicals. It is non-toxic, an antioxidant, a water barrier and even, in some cases, a fire retardant.

The first state-of-the-art, commercial-scale lignin separation plant was started last year in Plymouth, NC, USA.  This is a Domtar facility and it is believed this facility will make greener and more cost effective products than synthetic (petrobased) elastomers and polymers.  Lignin may be used as an additive for “tape, labels, and wood adhesives. For primary adhesives, lignin could be used as a “tackifier to pressure sensitive resins, a binder for wood, wood composites and other hot melt adhesive renewables, a plasticizer for oils, a base polymer for wood substrates and could displace phenol-formeldehyde binders.”  With all of those commercial opportunities one might wonder why the development has taken so long.  After all, we generate at least 73,000 tons of lignin per year and only recover 2%.  We can criticize the petro business for being fossil-oriented but they sure moved more quickly than the paper industry.  Honestly, I think it goes back to priorities and culture.  If end of life is not part of your mindset it just doesn’t happen.  Green adhesives and natural polymers are estimated to represent 30 – 40% of all the raw materials in adhesive formulations.  This will only continue to grow as technology evolves.  Lignin is part of this evolution.  Just recently, Kaleigh Reno, a graduate student from the University of Delaware, announced she and other researchers had developed a process that “converts lignin fragments into a compound called ‘bisquaiacol (BGF)’ which could be an alternative to bisphenol (BPA) which has been determined to be a carcinogen. BGF has the same properties as BPA and could be marketable in under five years.

“Before we synthesize it we need to make sure it is less toxic, less hazardous to human health and still has the desirable properties of BPA,” said Reno.

We know from previous work on lignin that it is an abundant material.  It is chemically aromatic and it is known to provide rigidity and be a high performance polymer.

Reno said they know the molecular structure of BPA plays a role in disrupting natural hormones such as estrogen. 
BGF was designed so that is it incapable of interfering with hormones but retains the desirable thermal and mechanical properties of BPA.

The use of lignin as an alternative to petrochemical polymers will continue to mature, just like IBM’s new ultra-strong material Titan and Hydro that is recyclable.  This is a fascinating story and only occurred because of an accident in one of IBM’s labs.  Jeannette Garcia forgot to add a component to a simple polymerization reaction.  Instead of becoming a slurry it formed a polymer, a very, very strong one.  Ah, mistakes.  Garcia explains, “I couldn’t even get it out of the flask. I had to break the glass with a hammer.  The polymer actually survived the glass breaking, so I hit it with the hammer and it didn’t seem to break.  I thought, ‘hmmm, there could be something to this.’ Further study revealed, “it’s stronger than existing thermosetting resins (epoxy, phenolic, etc.) by about threefold.”

IBM calls Garcia’s development “computational chemistry.”  This technique “revealed that there was a hidden, stable precursor to the material, meaning it could be further tweaked.”  Cure it at high temperature and it’s so hard it could be used in aerospace applications.  Cure it at low temperatures and “you get an organogel that sticks to itself, healing gaps and scratches.”  And, there were more surprises. Both of these materials, the low and high cure polymers, called Hydro and Titan respectively, can be reduced to their component monomers very simply.  Titan disappears in strong acid and Hydro in ordinary water.

As Science Magazine says:  “The greatest asset of super-strong materials is generally also their greatest liability:  nothing affects them.  They have incredibly great stability – mechanical, chemical, thermal – but it kind of creates tension with the idea of recyclability.”  Strength, or recyclability?  In this case, “IBM has proven we can begin to design molecules that are incredibly tough, incredibly durable but are still recyclable.  Things don’t have to be in tension.”

In this case we have, at first glance, harmony.  Who knows where Titan and Hydro will go.  I assume it will be years before either is commercialized.  Like lignin there is much to develop.  And, this is first generation.  Wind turbines and gassification are further down the road and proven technologies that still need further development. It’s interesting to note that Stan Avery’s PSA product evolved in the mid 30s and early 40s.  Look what has developed in decoration technology since those days.  And, there is more to come.  Hang on to your hats! My major wish is that whether it be pressure sensitive or bees or lignin or Titan and Hydro we learn from past mistakes and design holistically with completeness of life in mind. Completeness, in my view, means either no by-product or a solution for by-product that is sustainable and economically competitive.

Another Letter from the Earth.

Calvin Frost is chairman of Channeled Resources Group, headquartered in Chicago, the parent company of Maratech International and GMC Coating. His email address is cfrost@channeledresources.com.
  • Adhesives Update

    Adhesives Update

    Greg Hrinya, Associate Editor||April 7, 2017
    Label adhesives must meet a variety of performance and manufacturing requirements.

  • The Future of Flexo

    The Future of Flexo

    Steve Katz, Editor||April 7, 2017
    Recruitment and proper training are paramount to the health and future of flexography.

  • Latin America’s Label Market

    Latin America’s Label Market

    Greg Hrinya, Associate Editor||March 13, 2017
    Competition and emerging print technologies define this region.