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Editorial Pieces

The following list includes opinion pieces (editorials) written by Dr. Hubbe, mostly published in the journal BioResources. Click on the item to open up an abstract and (in the case of open access items) find a link to the PDF.

Hubbe, M. A. (2022). “What to do with toxic, contaminated cellulose-based adsorbents,” BioResources 17(1), 3-6.

This editorial considers the end fates of toxic materials, such as heavy metals, dyes, and synthetic organic compounds, which can be recovered from polluted water by using bio-based adsorbents. The point of the editorial is that insufficient research attention has been paid to the final fate of such contaminants. By contrast, much is known regarding factors affecting the adsorption capacities and rates of adsorption onto cellulose-based materials. Highly contaminated solutions are produced during the regeneration of biosorbent materials. Eutectic freeze crystallization potentially could be used to isolate relative pure compounds of heavy metals from such solutions. Alternatively, biochar can be prepared from cellulosic material in such a way as to achieve strong attachment to certain pollutants. Such biochar, after its use as an adsorbent, could be placed in the ground, where it can be expected to remain stable as sequestered carbon. A high ion exchange capacity of such biochar has potential to reduce the rates of leaching, which could otherwise lead to contamination of groundwater near to landfill sites. As shown by these examples, some promising answers to the final fate of contaminants may conform to a “circular economy” model, whereas other promising answers may conform to a “cradle-to-grave” viewpoint.

Hubbe, M. A. (2021). “Energy efficiency – A particular challenge for the cellulose-based products industries,” BioResources 16(4), 6556-6559.

Wood-processing facilities, including pulp, paper, lumber, and engineered wood facilities, use large amounts of energy for such purposes as evaporative drying and the curing of adhesives. Much of that energy is already being supplied by the incineration of biomass, and there is opportunity to increase the proportion of renewable energy that is used. Specific changes can be made within such factories that allow them to come closer to what is thermodynamically possible in terms of avoiding the wastage of exergy, which can be defined as useful energy. Savings in exergy are often obtained by optimization of a network of heat exchangers within an integrated system. No steam should be allowed to leak to the atmosphere; rather the latent heat (due to phase transitions) and sensible heat (due to temperature changes) are recovered during the heating up of incoming air and water, ideally at a similar range of temperatures. Thus, by a combination of process integration and full utilization of cellulosic residues generated from the process, even bio-based industries can be made greener.

Hubbe, M. A. (2021). “When defects dominate: Rheology of nanofibrillated cellulose suspensions,” BioResources 16(1), 16-18.

Conventional rheological tests can be difficult to carry out in the case of suspensions of nanofibrillated cellulose (NFC). Such suspensions tend to migrate away from the walls of a rheometer device, leaving a low-viscosity layer. The very high aspect ratio of typical nanofibrillated cellulose particles favors formation of tangled clusters. But application of hydrodynamic shear can cause fragmentation of those clusters. It is proposed in this essay that some focus be placed on the fragments of entangled clusters of NFC and interactions between them at their fractured surfaces. The condition of near-uniform, defect-free structures of nanocellulose spanning the volume within a sheared suspension might be regarded as an unlikely circumstance. Isaac Newton started with a very simple equation to start to understand rheology. It is proposed that a similarly bold and simplified approach may be needed to account for the effects of broken entangled clusters of NFC on flow phenomena, their assessment, and their consequences related to industrial processes.

Hubbe, M. A. (2020). “What would J. Willard (Gibbs) do?” Int. J. Wettability Sci. Technol. 1, 169-170.

When flipping through the inaugural issue of International Journal of Wettability Science and Technology, my attention was drawn to an article by Makkonen titled “Faulty Intuitions of Wetting.” 

For years I have been in awe of J. Willard Gibbs, who over years of careful analysis and intuition came up with the foundations of thermodynamics.  Gibbs’ work has provided a firm foundation upon which subsequent scientists and technologists have built not only theories, but also practical equipment and engines that power our modern society.  So the question arises, if thermodynamics has been so reliable, why do researchers such as Makkonen keep stumbling across situations where those concepts do not seem to work for contact angle and wettability issues?  I wonder what Gibbs would be thinking if he were to read articles published in the last 60 years in this academic discipline.

When first reading Makkonen’s article, my reaction was relief.  I was pleased to be able to read a studied explanation of aspects that had been bothering me since 2015, when I was in a group that wrote an article titled “Contact angles and wettability of cellulosic surfaces: A review of proposed mechanisms and test strategies” (BioResources 10(4), 8657, 2015).  When I had started working on that review article, my thinking was something like “This is a mature field.  All that’s needed is a review article showing how the concepts apply in the case of cellulosic surfaces.”  But my expectations were soon dashed once I began to read the literature.  In particular, I was struck by the work of Fowkes and co-authors, whose 1990 article “Interfacial interactions between self-associated polar liquids and squalene used to test equations for solid-liquid interfacial interactions” (Colloids Surf. 42, 367) pretty much destroyed my confidence in any of the prevailing analyses based on such concepts as acid-base components of surface energy, among others.  Also I sensed an alarming disconnect between some researchers who paid attention to surface roughness issues (including the Wenzel equation) and those who ignored such issues while attempting to fit data to ever-more complicated equations based on the purported free energy of perfectly smooth surfaces, which they assumed could be relevant for real situations.

Makkonen raises troubling questions about some issues that are yet more fundamental than those we mainly considered in our 2015 article.  He makes the point that contact angles often represent situations where a contact angle “gets stuck”.  As Gibbs would be quick to note, his thermodynamic theories apply only when processes occur in a reversible manner, not when things get stuck or build up until they undergo sudden change.  Makkonen suggests that the free energy of a solid surface can be used as the basis of the Young equation, which governs contact angles.  But is there a reversible way to form a solid surface?  As yet, there does not seem to be a way to separately evaluate the interfacial free energy between (a) a droplet and a solid, together with (b) the interfacial free energy between the same solid and an atmosphere.  My hunch is that Gibbs would accept the existence of a difference between those two terms (as in Dupré’s definition of the thermodynamic work of adhesion), but probably not either of those terms as a separate thermodynamic quantity.

Hubbe, M. A. (2020). “Saving the planet: What is the role of biomass?” BioRes. 15(1), 1-2.

Scientists predict continuing increases in average global temperatures. Consequences include sea level rise, shifts in agriculture, and severe stress on many species, including our own. Can biomass be used to mitigate climate change? It is proposed in this essay that the answer is “yes, but”. Yes, trees and other plants will continue to serve as “the lungs of the planet,” converting CO2 to O2 by photosynthesis. But saving the world will not be easy. Biomass scientists will not be able to solve the problems alone. Rather, mitigation of problems related to climate change will require parallel efforts. We will need to get energy also from the sun, from wind, from water, from improvements in efficiency, and from societies learning to live peaceably, while showing restraint regarding jet travel.

Hubbe, M. A. (2019). “Why, after all, are chitosan films hydrophobic?” BioResources 14(4), 7630-7631.

Chitosan has a molecular structure very similar to that of cellulose, except that one of the –OH groups on each repeating unit (at the C2 position) is replaced by an amine group. Since chitosan has abundant water-loving groups and is soluble in weakly acidic aqueous solution, one might expect films prepared from casting of chitosan solutions to be hydrophilic. Experiments have shown wide variability, often indicating a hydrophobic character of the chitosan films. A 2008 article by Cunha et al. presented evidence suggesting that the apparent hydrophobicity was attributable to impurities. However, not all the evidence was consistent. In particular, extraction of chitosan film with methanol failed to increase the polar component of surface free energy. It is proposed in this editorial that the explanation can be found in a differing water-affinity of chitosan polymer segments, depending on their orientation. This explanation, if valid, is consistent with differences in the hydrophilic or hydrophilic character of different crystalline faces of cellulose.

Hubbe, M. (2019). “BioResources to serve as host for Fundamental Research Symposia archives,” BioRes. 14(1), 1-2.

The Fundamental Research Committee (FRC), founded in 1956 to organize regular symposia among pulp and paper scientists, has been aiming to widen access to their archival published proceedings.  The FRC decided that it would be best to make their published work freely available on the web rather than continuing to offer CD versions for sale.  They wanted to work together with an entity having experience with open access publishing.  The FRC has selected BioResources as that entity, based on our 13-year record of open access service to the same branch of science and technology.  BioResources is honored to take on this role and accordingly will henceforth prominently list the “Fundamental Research Symposia Archives” on our web page with links to the FRC content.

Khider, T. O., and Hubbe, M. A. (2018). Towards rational utilization of indigenous plant resources,” BioRes. 13(4), 7172-7174.

The world has huge floral diversity, whereas there often is poor and irrational utilization, especially of indigenous plants and residues from agricultural processes. Trees, shrubs, and herbs can have multiple uses at different levels as medicines and sources of lignocellulosic materials. A fuller and more rational utilization is needed, with interaction of international and national communities, to raise the awareness of local people, governments, and industrial entrepreneurs of the floral wealth that is waiting to be utilized more effectively.

Hubbe, M. (2017). “To repair or not to repair cracked wood,” BioRes. 12(4), 6904-6906.

If only wood could be defect-free, then the minimum strength of solid-wood beams and other structures could be much higher. Structural failures could be avoided, and-or less material might be required in some applications. Cracks in wooden structures can be filled with adhesives or with thermoplastic composite material. But to approach the intended strength of defect-free wood, it is necessary to use other strategies such as glued rods and surface patches. The ultimate answer may lie in better species selection, tree breeding, forestry strategies, lumber cutting practices, and lumber drying practices to avoid cracks in the first place.

Hubbe, M. A. (2017). Book review of an open textbook: Sustainability: A Comprehensive Foundation,” BioRes. 12(3), 4497-4499.

Paper was once the lightest, lowest-cost way to make information widely available in a form suitable for study and self-improvement. But paper-based textbooks, in the modern era, tend to be heavy and they can also strain the budgets of typical students. Given the fact that you are now reading an open-access journal, you may understand why many faculty members would possibly want to use an open-access textbook for some of their courses. This editorial considers one such course, and the assessment is generally favorable. But in addition to the classroom, a good open textbook may be regarded as a suitable foundation for one’s research. By citing an open textbook in the introduction to your research article, you can provide your readers with the option of gaining enough background to better appreciate your latest research findings.

Hubbe, M. A. (2017). Why I don’t do academic social media…or do I?,” BioRes. 12(2), 2252-2253.

A communications scholar at our university asked me recently whether I would take part in a debate about academic social media services such as ResearchGate. Yes, I responded, as long as I don’t have to argue the affirmative – that such online systems are necessarily a good thing. Personally I do not count myself as a user of academic social media, but I can easily understand why others could make an opposite decision. Academic social media can provide a way to get copies of full-length published articles, to pose questions to other researchers, to get various questions answered, and in general to foster relationships with well-networked and possibly influential people within one’s academic field. Or, like me, you might just enjoy having something mildly annoying that is fun to complain about.

Hubbe, M. A. (2016). “Catalysts inspired by life,” Biofuel Res. J. 11, 430-430. DOI: 10.18331/BRJ2016.3.3.2

Biosynthetic processes take place throughout our world with astonishingly high precision and rapidity to create biological systems, trees, and even such complex products as our own bodies.  Though each of the chemical reactions involved in creating something as complex as a tree is thermodynamically possible, there is nearly zero possibility of creating complex biomaterials without the use of enzymes.  Breaking down those biomaterials is somewhat easier – even fire can accomplish that – but still it is enzymes that make most biodegradation possible throughout the world.  An enzyme acts as a catalyst, accelerating and often helping to direct the path of a reaction that would not otherwise take place fast enough or which might otherwise tend to take a different reaction path from what is needed.

But enzymes are not the only kinds of catalysts.  The present issue of Biofuels Research Journal, for instance, has an article that shows how zeolites can help direct the reactions of vapors of pine wood pyrolysis.  Catalysts made by humans often follow our ancient tradition of alchemy:  selecting or modifying minerals or metal ores in the hopes of obtaining something valuable.  In his book The Alchemy of Air, Thomas Hager describes how the chemical engineer/inventors Fritz Haber and Carl Bosch managed to convert gaseous nitrogen into ammonia.  The key was to use an impure iron wire, along with incredibly high pressure and high temperature.  It is estimated that one-half of the nitrogen atoms presently incorporated into your own body, right now, are a direct result of the Haber-Bosch process.  Yes, nitrogen also can be “fixed” by biological processes, but not at a rate that would support the current human population, and humanity had to discover another catalyst in order to sustain the growth of civilization.

Maybe humanity’s current challenge involves advancing beyond “alchemy” and returning to biology as a main arena for catalysis.  Such an approach is represented by the article dealing with biogenic hydrogen production.  Just as in the case of the inorganic catalysts discovered by Haber and Bosch, it takes a great deal of patience and many unsuccessful attempts in order to come up with high-performing enzymes, which may be regarded as biocatalysts.  Many factors may degrade or inhibit the activity of a catalyst.  As emphasized in the review article “Green biodiesel production,” we can expect catalysts to take center stage as humanity grapples with the challenge of sustainability in this increasingly crowded and often hungry world.  These catalysts will take many forms – from transition metal complexes, to enzymes, to pieces of rusty wire.  But without progress in the field of catalysis there is no way that all of us will be able to survive on this planet.

Hubbe, M. A. (2016). “My production facility, my laboratory of discovery,” BioRes. 11(4), 8116-8118.

By exercising of one’s curiosity, in combination with a lot of persistence, it is possible to solve some seemingly intractable problems. Many readers of this journal will have spent much, if not all of their careers, in university laboratories. In such settings there is an understandable emphasis on understanding underlying reasons. In other words, one is expected to focus on “why things happen” rather than just getting results. But if such an approach works well at the university, how about applying it at the production facility? This editorial features the stories of a man who was brave enough to spend his career asking “why” questions while working to improve the operations of paper mills.

Hubbe, M. A. (2016).Paper or plastic? Yes, but not as a mixture,” BioRes. 11(3), 5656-5657.

As expressed by the chorus lyrics of a song by Dan Einbender, “it really isn’t garbage ‘til you mix it all together. It really isn’t garbage ‘til you throw it away. Separate your paper, plastic, compost, glass and metal. Then you get to use it all another day.” It’s worth paying attention to these lyrics once again in the face of yet another type of product that is starting to show up in stores. Extruded sheets of polyethylene (no. 2 plastic) with as much as 80% ground calcium carbonate content are being sold as “paper”. Calcium carbonate is widely used as a component of real paper. However, it rubs me the wrong way when the word “paper” is being used to refer to something that has no fibers in it and is not formed on a screen and dried. My more serious concern is that such materials, if they become widely used, have the potential to contaminate paper recycling operations.

Hubbe, M. A., and Lucia, L. A. (2016).BioResources: Ten years of service for the progress of the science and technology of lignocellulosic products,” BioRes. 11(1), 1-2.

The co-editors of BioResources note the completion of our first ten years. We think that the journal can be judged as a success based on having achieved an impact factor of about 1.4 each year since 2009 and having reached a publication rate of about 700 articles per year. We strive to be a “people’s journal” serving scientists, students, and society. We plan to continue emphasizing editorial pieces and review articles, which supplement our main service of publishing peer-reviewed articles dealing with the science of lignocellulosic materials, chemicals, and their uses. We also support undergraduate scholarship in our academic department, including tuition payment, opportunities for pre-editing work, and support for undergraduates to attend conferences, etc.

Hubbe, M. A. (2015).Oops, I thought that those books had been deacidified,” BioRes. 10(4), 6305-6309.

Major libraries have been placing increasing reliance upon non-aqueous mass deacidification in an effort to avoid hydrolytic decomposition of the cellulose during storage of bound volumes. Such decomposition is especially a problem when the printing papers used in manufacture of the books have been prepared under acidic conditions, using aluminum sulfate. But there is reason to doubt that the widely used non-aqueous treatments, in which “alkaline reserve” particles are deposited in the void spaces of the paper, can achieve neutralization of acidity throughout the paper structure under the conditions most commonly used for treatment and storage. Anecdotal evidence suggests that alkaline particles such as CaCO3, MgO, Mg(OH)2, or ZnO can be present for long periods of time adjacent to acidic parts of cellulosic fibers without neutralization of the acidity, especially the acidity within the fibers. If these phenomena can be better understood, then there may be an opportunity to use a high-humidity treatment of certain “deacidified” books in order to achieve more pervasive protection against acid-induced degradation.

Hubbe, M. A. (2015). What next for wood construction/demolition debris?” BioRes. 10(1), 6-9.

Residents in localities throughout the world voluntarily participate in the routine recycling of household wastes, such as paper, metals, and plastics containers. But when a house in their neighborhood gets built or torn down, most of the debris – including wood waste – gets landfilled. Such a waste of material suggests that there are opportunities to add value to these under-utilized resources. The great variability, as well as contamination, pose major challenges. It is recommended that reclaimed wood be primarily used in the manufacture of durable goods, and then whatever is left over be used for energy (or heat) generation.

Hubbe, M. A. (2014). Puzzling aspects of the hydrophobic sizing of paper and its inter-fiber bonding ability,” BioRes. 9(4), 5782-5783.

Internal sizing agents make it possible to prepare water-resistant paper from an aqueous suspension comprising water-loving fibers and an emulsified hydrophobic agent. Why doesn’t the hydrophobic treatment get in the way of inter-fiber bonding? The answer appears to involve the order in which nano-scale events happen during the manufacture of paper. It appears that the inter-fiber bonded areas develop first. Molecular distribution of the hydrophobic agents appears to happen later, especially during the later stages of evaporative drying. The topic seems to be crying out for someone to carry out appropriate experiments to shed more light on the mechanism.

Hubbe, M. A. (2014). Zipping backwards the other way – Yet another unique aspect of cellulose,” BioRes. 9(3), 3759-3760.

Readers of this journal may be keenly aware of cellulose’s remarkable attributes, such as high stiffness, insolubility in just about everything, resistance to enzymatic attack, dimensional stability in the lengthwise direction, and toughness associated with the alternating crystalline zones and less organized regions. But if you dissolve cellulose and then allow it to recrystallize, the resulting crystals are at the same time radically different, and yet remarkably similar in most respects to the native form. Exactly half of the macromolecules in regenerated cellulose have been reversed 180 degrees in their direction. The behavior of dropped pencils can help explain why this happens.

Hubbe, M. A. (2014). Recycling paper recycling,” BioRes. 9(2), 1828-1829.

What do you do after a product has served its function and is no longer needed? Ideally, you recycle it. What do you do if people have neglected or forgotten so much of what has been learned in recent years about paper recycling? Well, one of the things that someone can do is to write a book. Very little of the contents of such a book may be new. But the book itself can be highly valuable, representing a lot of effort to select and organized material that will be helpful for the current and upcoming generations of papermaking technologists. This editorial describes a new book by Dr. Pratima Bajpai entitled Recycling and Deinking of Recovered Paper. Readers who deal with the recycling of paper will probably want to have a copy of it on a handy shelf.

Hubbe, M. A. (2013). “On Paper – A celebration of two millennia of the work and craft of papermakers,” BioRes. 8(4), 4791-4792.

Those of us whose lives have been deeply touched by the technology of papermaking – and many others besides – are in for a real treat this coming fall when the book On Paper is scheduled to be published. The author, Nicholas Basbanes, employs an engaging, personalized approach as he brings to life the story of how paper has enabled the progress of civilization throughout two millennia. I first learned about Nick’s grand project, to capture the most intriguing aspects of paper’s story, during a re-broadcast of his hour-long interview that was presented on the CSPAN TV network. His enthusiasm is infectious, and it can be an uplifting experience to have him as a tour-guide to “all things paper”.

Hubbe, M. A. (2013). Life in the Forest Canopy,” BioRes. 8(2), 1508-1509.

Scientists have been devoting increased time and attention to the tops of trees. As made clear by results of their studies, the environment of the forest canopy is teeming with life. Perhaps because the crowns of trees are difficult for people to reach, and due to the micro-climates within them, they hold a rich and diverse collection of life forms. Advances in the use of ropes, ladders, and suspended walkways is now making it possible for humans to be more frequent visitors to these realms.

Hubbe, M. A. (2012). “The Wood Age – Part of our past, but should we wish for it as our future?” BioRes. 7(4), 4499-4500.

A new book by Radkau, Wood. A History, provides telling insight into the cleverness and also into the short-sightedness of humans in their almost uninterrupted dependence on forest resources. This essay touches upon the earliest evidence of prehistoric wood-based technologies – showing examples where humans have tended, in many generations, to exhaust their readily available resources. Beginning in the Industrial Revolution a greatly expanded usage of first coal and the petroleum have tended to take some of the pressure off of the use of wood as a fuel source. But there are early signs that the situation may be changing soon. Large wood-to-liquid-fuel facilities are being talked about. Though the usage of wood for fuel has the potential to be a sustainable enterprise, human history suggests we should exercise caution.

Hubbe, M. A. (2010). The implementation of findings published in scholarly articles,” BioRes. 5(4), 2024-2025.

Articles published in scholarly journals, such as this one, tend to be mainly addressed to researchers at universities. Industrial follow-up and implementation of results from a scholarly article appears to be the exception, rather than the rule. Research grant specifications, as well as university policies, favor the generation of new knowledge, rather than the implementation of good ideas. But without patent protection, corporations have low motivation to expend the considerable effort to reduce ideas to practice after they have been openly published. The author speculates that the situation could be much more dynamic if there were a system of priority of implementation. According to such a system, the first company to successfully implement an idea that first appears in a peer-reviewed journal article, as validated by its debut in the marketplace, would have a grace period during which competitors would have to pay them a fee to sell a generic version of the same thing.

Lucia, L. A., and Hubbe, M. A. (2010). Can lignocellulosic biosynthesis be the key to its economical deconstruction? BioRes. 5(2), 507-509.

It is ironic to think that the venerable pulp and paper industry is now considering ways to degrade cellulose. This notion can be understood as a way that the industry can face a protracted downturn in profitability and ever-mounting socio-economic pressures to enhance the efficiency of biofuels production. Many approaches have been recently taken to deconstruct cellulosic biomass, but this Editorial explores one key that may start to explain the increasing momentum in the biofuels community – biotechnology. Two approaches appear to be possible as scientists search for an effective way to unzip cellulose to its key constituents through the use of biotechnology. On the one hand, there are efforts to re-engineer the chemical composition of the tree, rendering it more digestible by enzymes and decreasing the need for mechanical or chemical pretreatment. On the other hand, what we are learning about lignocellulose biosynthesis can be of potential help in designing more efficient systems to essentially reverse that process.

Hubbe, M. A., and Buehlmann, U. (2010). A continuing reverence for wood,” BioRes. 5(1), 1-2.

Our ancestors knew a great deal about wood. They had to in order to do well in life. Wood has played a dominant role in human infrastructure for many generations, and for most of that time woodcraft has depended on the decentralized knowledge passed down among families and guilds. This editorial, while celebrating the knowledge, skills, and insights of the woodworkers of past generations, also calls for a renewed attention to wood’s unique character, including characteristics that today are too often classified as “defects.” We may need to take lessons from generations past to truly derive the best value from wood resources.

Hubbe, M. A. (2009). ‘Retro-,’ An emerging prefix for future technological development?” BioRes. 4(1), 1-2.

It is proposed that the prefix “retro” can serve as an irreverent, but timely buzzword for the development of new technology to meet human needs. Society has carried out experiments at a very large scale for the last century or so to meet our collective needs though the use of fossil-based fuels and synthetic materials. Those experiments have seemed successful in the short term, feeding more of us and supplying a lot of us with rising standards of living. But the experiments often have failed us in terms of sustainability. A health crisis, global warming, and resource depletion are urgent problems caused by careless use of fossil fuels and related synthetic organic chemicals. The prefix “retro,” as in “retrotechology,” signals a disciplined return to a reliance on nature-based products, as well as a respect for the beauty, but also the fragile character of our natural environment.

Hubbe, M. A. (2008). Are lignocellulosic resources too valuable to burn?” BioRes. 3(2), 295-296.

Lignocellulosic matter often can be counted as a renewable resource, since it is produced by photosynthesis. But there are limits to how much biomass our society can use in a sustainable manner. People can debate whether or not it makes sense to use a substantial portion of lignocellulosic materials as a source of liquid fuel. This essay gives a qualified affirmative answer to the question in its title. However, combustion of lignocellulosic resources can be considered as wasteful and uneconomical, in the long run, if it is inefficient, if it fails to displace the combustion of fossil fuels, or if it displaces a higher-end use, for which there are available customers. In particular, it seems unlikely that combustion of fuels derived from lignocellulosic biomass can, by itself, solve problems that stem from society’s excessive thirst for motor fuels.

Hubbe, M. A., and Lucia, L. A. (2007). The ‘love-hate’ relationship present in lignocellulosic materials,” BioRes. 2(4), 534-535.

The three main types of chemical components in wood are cellulose, hemicellulose, and lignin. These three components have rather different physical and chemical characteristics. In some respects, the three types of materials can be described as “incompatible.” However, most of the biomass existing on the planet depends on their successful interactions. It can be useful to think of wood as being a natural composite structure. Concepts related to composites also are useful as we envision possible new and improved uses of wood-derived materials.

Hubbe, M. A. (2007). When is a tree not a resource? BioRes. 2(3), 332-333.

Although this journal mainly considers the study of cellulosic materials as sources of structural wood, fibers, chemicals, energy, and products such as paper, it would be short-sighted to view all trees as existing in order to meet such needs. An individual tree may have multiple roles, from a human perspective. The point of this essay is that different groups of trees ought to be managed in one of four ways – as crops, as natural habitat, as an awe-inspiring heritage, as in the case of national parks, and as dear friends in our yards and along our boulevards.

Hubbe, M. A. (2007). Appropriate technology in an age of renewables,” BioRes. 2(2), 146-147.

In this editorial the author proposes that scientists and technologists can play essential roles in the selection of technological alternatives that are appropriate to people’s long-term needs. Lessons learned in the 1970s and 80s, involving the design of simple and reliable mechanical systems for underdeveloped regions, can have relevance today in an increasingly interdependent, crowded, and polluted world. Specialists can help in two ways to promote technologies that make sense, providing for future well-being, and minimizing risks. First, we can exercise personal judgment in our work, as we pursue technological progress. We need to consider whether the likely products of our work are compatible with the world that we want to leave for our grandchildren. Second, we can provide guidance to our fellow citizens, as society grapples with the political and economic choices associated with progress.

Hubbe, M. A. (2007). Incinerate, recycle, or wash and reuse,” BioRes. 2(1), 1-2.

What is the best way to minimize the environmental impact of using a product such as paper? Three debating teams were formed within a university class. One team advocated increased recycling of paper. Another team pointed to evidence showing reduced environmental impact and lower net CO 2 emissions if the paper is incinerated rather than recycled. A third team advocated the replacement of paper by items such as porcelain plates and video screens, cutting costs and reducing waste by multiple reuse.

Hubbe, M. A. (2006). From here to sustainability,” BioRes. 1(2), 172-173.

Many readers and contributors to BioResources are working to develop sustainable technology. Such research attempts to use products of photosynthesis to meet long-term human needs with a minimum of environmental impact. Archeological and historical studies have concluded that the long-term success or failure of various past civilizations has depended, at least in part, on people’s ability to maintain the quality of the resources upon which they depended. Though it is possible for modern societies to learn from such examples, modern societies are interconnected to an unprecedented degree. It is no longer realistic to expect one region to be immune from the effects of environmental mistakes that may happen elsewhere in the world. Research related to renewable, lignocellulosic resources is urgently needed. But in addition to the research, there also needs to be discussion of hard-hitting questions, helping to minimize the chances of technological failure. The next failed civilization may be our own.

Hubbe, M. A. and Lucia, L. A. (2006). BioResources – An online scientific journal devoted to lignocellulosic materials for new end uses and new capabilities BioRes. 1(1), 1-2.

In this inaugural issue, the Co-Editors of BioResources would like to welcome you. In your role as a reader, we welcome you to download scholarly articles and opinion pieces; this is an open-access journal, providing a maximum of potential impact. BioResources will deal with new and emerging uses of materials from lignocellulosic sources, including wood and crop residues. Topics will include biofuels, biomass-derived chemical products, papermaking technology, and other new or improved uses of biomaterials. We also would like to welcome you as a prospective author. Our goal is to maintain very high standards of peer-review, as well as providing a mix of scholarly research articles, review articles, and editorials. By using an automated, online system of review and publication, we hope to accelerate scientific discourse. Our hope is to contribute to progress in the direction of a post-petroleum economy, taking advantage of the renewable, biodegradable, and relatively abundant nature of materials from lignocellulosic sources.

Hubbe, M. A. (2006). “Does production of the world’s highest-tonnage manufactured item often involve nanotechnology?” Nanotechnol. Perceptions 2(3), 263-266.


            Depending on the definition that one chooses to use, it can be claimed that the paper industry is the world’s largest practitioner of nanotechnology.  Alternatively, by using certain narrower definitions,1 one might claim that technology currently in widespread use by papermakers all fails to qualify as nanotechnology.

            The worldwide annual production of paper products intended for printing and writing is about 104 million metric tons.2  A large proportion of those tons, possibly more than half, are produced from fiber mixtures to which about 0.02 to 0.2% of nanoparticles have been added, on a dry-mass basis, in a sequential combination with at least one very-high-mass cationic polyelectrolyte product.  Commonly used nanoparticles for such applications include colloidal silica suspensions, the primary units of which usually are within the range of 2 to 5 nm in diameter.3  Many of the colloidal silica products are self-assembled in such a way that they consist of fused chains of primary particles.4  Alternatively, papermakers also can use sodium montmorillonite (“bentonite”) particles,5 which have a thickness dimension of about 0.9 nm when fully exfoliated.6  The sequential treatment with the polyelectrolyte (usually an acrylamide copolymer or cationic starch) and nanoparticle typically results in a marked reduction of the time needed for water to flow from a paper sheet as it is being formed,7 an effect that goes well beyond what can be achieved in the absence of nanoparticles.

How I have used the term

            Two years ago the Pira organization (Leatherhead, Surrey, UK) asked me to prepare a comprehensive report related to emerging technologies that are likely to affect the use of chemicals during the manufacture of paper.8  In preparing to write that report I looked carefully at a broad range of publications dealing with nanotechnology.  My criterion for considering an idea worth mentioning in the report was that the implementation step should involve the admixing of nano-objects with an aqueous suspension of cellulosic fibers.  Consistent with this idea, I proposed that lottery tickets might be prepared from paper to which finely divided quantum dot material9 had been added.  The light absorbance behavior of a batch of nano-size quantum dots is unique, very hard to replicate, and a simple device could be assembled to verify that a winning lottery ticket had the correct spectrum and was not forged.  I also suggested some ways in which fibers in an aqueous suspension might be treated in-situ with self-assembled multilayers of polyelectrolytes in order to impart unique properties, such as tunable levels of hydrophobicity.

            My working definition of “nanotechnology,” for purposes of communication with other paper technologists, goes something like this:  “Nanotechnology happens when objects having at least one dimension smaller than 10 nm are used or assembled outside the walls of a research laboratory to achieve repeatable, useful effects that cannot be achieved in the absence of the objects.”  Note that by this definition, the idea of adding quantum dot material during papermaking would not qualify.  Probably words like “science” or “emerging technology” ought to be used in place of just “technology” when describing nascent ideas that have not yet been tested or implemented.  The same thinking also would tend to exclude the concept of preparing polyelectrolyte multilayers on fibers to be used in papermaking.  Although the concept has been demonstrated for purposes of increasing paper’s strength,10 there is no indication yet that the concept will be commercialized.  Recent research suggests that very similar strength effects can be achieved less expensively by deposition of polyelectrolyte complexes,11-12 an approach that requires no changes to the equipment already being used to manufacture paper.

Narrower criteria for “nanotechnology”

            The dewatering technology, as mentioned in the second paragraph, appears to meet the criteria of “using objects having at least one dimension smaller than 10 nm, outside the walls of a research laboratory, to achieve repeatable, useful effects that cannot be achieved in the absence of the objects.”  It must be admitted, however, that the definition used here strays rather far from the field of precision engineering that Norio Taniguchi13 had in mind when he coined the term nanotechnology.  As noted by Ramsden,14 nanotechnology can be defined as deliberate placement or orderly self-assembly of objects in the nanometer range.  The word “deliberate,” suggesting a slow, mechanical process, seems to contrast sharply with the actuality of a state-of-the-art paper machine running at 1800 m/min.  The word “orderly” seems incompatible with addition of nanoparticles to a complex mixture of fibers, minerals, polyelectrolytes, and other additives undergoing partially suppressed turbulent flow.  Though precision engineering is required in the manufacture of the equipment being used to make paper, the process itself is designed to achieve a nearly isotropic mixing of all of the ingredients.  The nanoparticles achieve their unique benefits, in terms of faster dewatering, by a process that leads to random locations of the nanoparticles within the sheet of paper being formed. 

            Let’s make a final attempt to force papermakers’ use of nanoparticulate dewatering aids into a narrower definition of nanotechnology,1 which might include the words “deliberate manipulation and placement.”  In support of such usage, it is worth noting that the nanoparticles have no effect when added to papermaking suspensions that contain no high-mass cationic polyelectrolytes.7  Rather, the effects depend on the presence of adsorbed polyelectrolytes on fiber surfaces.  When nanoparticles are added subsequently to the mixture, they appear to (a) adsorb onto tails and loops of the adsorbed polyelectrolytes, (b) participate in the completion of polyelectrolyte bridges between different solid objects in the suspension, and (c) result in muscle-like contractions of the bridges, as polyelectrolyte segments continue to wrap themselves around the nanoparticle surfaces, due to attraction of opposite charges.7  Adjectives that might be used to describe this self-assembly process include “repeatable,” “eco-friendly,” and even “highly profitable” in many of the present paper mills where the technology is employed.

Clear thinking vs. feeling good and making money

            Although the paper industry is a major user of high technology, the fact that we make one of the lowest-cost manufactured items in the world sometimes can lead to an esteem problem.  Dangle a word like “nanotechnology” in front of a bunch of paper technologists, and it can seem to us like a ticket to the high-tech club.  Therefore, in the interest of clear thinking, probably it is best that papermakers avoid the use of the term nanotechnology when discussing the examples that I have listed in this essay.  It is not to be assumed, however, that clear thinking is the main goal in cases where the term nanotechnology might help attract a customer or allow an idea to become a candidate for a research grant.  We can only hope that educated customers and peer-reviewers will look beyond the labels and scrupulously judge the merits of each proposed idea.


1     J. Harris and D. Ure, “Exploring whether ‘nano-’ is always necessary,” Nanotech. Percep. 2 (2006) 173-187.

2     DeKing, N., Ed., “Global overview,” in Pulp & Paper Global Fact & Price Book, Paperloop, Inc., San Francisco, 2004, 1-6

3     Andersson, K. and Lindgren, E. “Important properties of colloidal silica in microparticulate systems,” Nordic Pulp Paper Res. J. 11 (1996) 15-21,57.

4     Iler, R. K., The Chemistry of Silica – Solubility, Polymerization, Colloid and Surface Properties, and Biochemistry, J. Wiley & Sons, New York, 1979.

5     Langley, J. G. and Litchfield, E., “Dewatering aids for paper applications,” Proc. TAPPI 1986 Papermakers Conf. (1986) 89-92.

6     Knudson, M. I., “Bentonite in paper:  The rest of the story,” Proc. TAPPI Papermakers Conf. (1993) 141-150.

7     Hubbe, M. A.  “Microparticle programs for drainage and retention,” in Rodriguez, J. M., Ed., Micro and Nanoparticles in Papermaking, TAPPI Press, Atlanta, 2005, Chapter 1, 1-36.  

8     Hubbe, M. A., Emerging Technologies in Wet End Chemistry, 91 pp., Pira International, Leatherhead, UK, 2005.

9     Brus, L. E., “On the development of bulk optical properties in small semiconductor crystallites,” J. Luminescence 31-2 (1984) 381-384.

10  Wågberg, L., Forsberg, S., Johansson, A., and Juntti, P., “Engineering of fiber surface properties by application of the polyelectrolyte multilayer concept.  Part 1: Modification of paper strength,” J. Pulp Paper Sci. 28 (2002) 222-228.

11  Lofton, M. C., Moore, S. M., Hubbe, M. A., and Lee, S. Y., “Polyelectrolyte complex deposition as a mechanism of paper dry-strength development,” Tappi J 4 (2005, 9) 3-7. 

12   Hubbe, M. A., “Dry-strength development by polyelectrolyte complex deposition onto non-bonding glass fibers,” J. Pulp Paper Sci. 31 (2005) 159-166.

13  Taniguchi, N.  “On the basic concept of nano-technology,” Proc. Intl. Conf. Prod. Eng., Tokyo, Japan Soc. Precision Engineering, 1974, Pt. 2, 18.

14  Ramsden, J.  “Nanotechnology in the papermaking process,” Proc. Improving Runnability for Papermakers, Madrid, Pira International, Leatherhead, Surrey, UK, 2006, Paper 17.