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Green Chemistry: The Nexus Blog

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Greening Up Our Ocean Blue

Posted by savsullivan May 28, 2015

Summer is upon us, and for many that means getting out on the water. Sailboats, powerboats, canoes, all are great choices for enjoying the open blue and we're not the only species that enjoys our boats. There are a host of organisms that love the underside of boats (algae, seaweed, barnacles, diatoms), but unfortunately most boat enthusiasts don't love these organisms. As this marine life builds homes on the boat hull the drag on the boat increases and the speed decreases, causing for greater fuel use, emissions to the atmosphere, and costs. To address these concerns, antifouling chemicals were introduced.


Antifoulants are any chemical used to inhibit the growth of this marine life on boats, and they are typically incorporated with the paint. Fifty years ago, a compound called tributyltin oxide (TBTO) came in to prominence in the antifouling scene. While wildly effective for the function it was to serve, over time it was determined that TBTO is quite persistent (with a half-life of more than 6 months in seawater) and chronically toxic to marine life. In the 1980’s many countries and organizations began to ban or severely restrict the use of TBTO as an antifoulant. In the United States, TBTO got its very own restrictive act, the Organotin Antifoulant Paint Control Act of 1988, and the US EPA and US Navy were charged with researching alternatives.


With this kind of history and these restrictions coming into play, it comes as no surprise that green chemistry and antifoulants have a bit of a relationship. TBTO was soon eliminated from all antifouling products and some replacements involving copper hit the market. Though this has since become what many consider to be a “regrettable substitution,” a replacement that has equal or worse effect compared to what it was replacing. Washington State in United States is now phasing out the use of copper as an antifoulant due to its toxicity effect on marine life.


Fortunately innovation is never too far away in the green chemistry space. There are several categories of alternative technologies including biocide-based (zinc or organic based), non-biocide-based (many are silicone based), and physical removal (ultrasonic sound). In the mid-1990’s the US EPA awarded one of its Presidential Green Chemistry Awards to a company (Rohm and Haas Company, now a subsidiary of The Dow Chemical Company) that developed an organic alternative (,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOI)) that has essentially zero bioaccumulation threat. DCOI has a half-life in seawater of one day, a stark contrast to TBTO’s six-month half-life, and is also significantly less bioavailable compared to earlier technologies in sediment and water.


Water is an important resource, both to us as scientists and as residents of Earth. As chemists we have a huge opportunity in many research areas to not only improve our interactions with our planet’s water in terms of toxicity impact (using the antifoulant story as an example), but in every aspect of our use of water as chemists. Green chemistry is the lens through which we can identify these opportunities for sustainable water-related innovation, and since every chemist uses water in one way or another, you can start looking through the lens today.




“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.


To read other posts, go to Green Chemistry: The Nexus Blog home.

The American Chemical Society’s Green Chemistry Institute (ACS GCI) Chemical Manufacturer’s Roundtable has received a $500,000 Advanced Manufacturing Technology Consortia planning grant from NIST. The grant will help the Roundtable develop greener and more efficient processes that can be used in chemical manufacturing.


In particular, the project team seeks to develop a Technology Road Map to propel the design of more energy-efficient alternatives to distillation, the most common separation process across the chemical manufacturing industry. Amit Sehgal Ph.D., of Solvay USA, Inc., the Roundtable Co-Chair stated, starting with molecular chemistry, they “envision a broader range of molecular properties or interactions (inter-molecular and molecular-material) to drive separations with an end goal of providing a logical decision tree based on intrinsic properties for an efficient, sustainable and least energy-intensive separation process.” Led by the ACS GCI Industrial Roundtables, this project is collaboration among the American Institute of Chemical Engineers Separations Division, the Computational Molecular Simulation & Engineering Forum, the Industrial Fluid Simulation Collective, the Pine Chemicals Association and several ACS GCI Industrial Roundtable member companies.


The ACS GCI Chemical Manufacturer’s Roundtable will attend the 19th Annual Green Chemistry and Engineering Conference July 14-16, 2015, as part of its yearly collaborations on advancing green chemistry. The industrial roundtable brings global industry leaders together to catalyze the beneficial implementation of green chemistry and engineering.




“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.


To read other posts, go to Green Chemistry: The Nexus Blog home.

Contributed by Jeffrey Whitford, Director of Global Citizenship at Sigma-Aldrich


In a world of constrained resources are you thinking about water use – specifically in your research?  If you answered yes, maybe you live in California, where Governor Jerry Brown has issued an executive order to reduce water usage by 25%, or maybe you live in another part of the world where access to water is a current or consistent challenge.


One of challenges that water conservation efforts face is a lack of incentive to conserve water.  There have been many articles written and even a series on NPR’s Marketplace about the low price we pay for water in many parts of the world, consistently undervaluing the resource.  And while the fervor of the alarm rises, our behavior is still not changing.  Without clear financial incentives to make conservation a priority, we have to take individual ownership beyond turning the faucet off while you brush your teeth, taking a three minute shower, or living with a brown lawn.


As a business, one of our most important responsibilities is to provide our customers with the products they need to complete their research, which requires that we maintain our license to operate.  You may ask what a license to operate has to do with water. As a manufacturer, water is a key part of what we do – whether it is an ingredient in a product or part of a manufacturing process.


As a business, Sigma-Aldrich utilized approximately 1.9 million cubic meters of water in 2014.  While this sounds like a lot, and it is, where and how that water is used is just as important and is part of being a good steward of resource usage.  Sigma-Aldrich also focuses on consistently monitoring and understanding where water is being used and the potential strains that exist on water infrastructure in the communities where we operate.


In 2013, Sigma-Aldrich reported a slight increase of water usage in high risk areas, from 11% to 12% of our total usage.  A majority of our water usage is in low risk areas, approximately 74%, while the remaining 14% is in medium risk areas.  A majority of our water usage is in St. Louis, Missouri, at the Production Campus responsible for the manufacture of a significant portion of Sigma and SAFC branded products.


Even with low financial incentives and a seemingly endless supply of water, since 2009 Sigma-Aldrich has saved more than two million cubic meters of water through efficiency efforts and by implementing a re-engineering program to rethink how we manufacture products to decrease the environmental impact of manufacturing in the reagents and chemical industry and ensuring that we maintain our license to operate.  We’ve taken this effort to the next level with an industry leading green chemistry quantification system called DOZN™, which captures the environmental improvements we make to products based on the 12 Principles of Green Chemistry.  You can learn more about this system on our website by visiting www.sigmaaldrich.com/dozn.


We all have a responsibility to think about how we use resources, but more importantly to think differently and to apply the 12 Principles of Green Chemistry in new and unique ways that challenge the status quo around resource utilization in research.  It’s the curious nature of research that can change the future.  The power of science can raise the bar.




“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.


To read other posts, go to Green Chemistry: The Nexus Blog home.


Message from the Director

Posted by ACSGCI May 27, 2015

Contributed by David Constable, Director, ACS Green Chemistry Institute®

So much has happened since my last Nexus article that I’m not sure I can do justice to everything.  Once again, this is a great problem to have!  In mid-April I was fortunate to be invited to the Autonomous University of Nuevo Leon in Monterrey, Mexico for their 3rd International Green Chemistry and Engineering Conference. I was not sure what to expect beyond the enduring hospitality of the people of Mexico, and I was certainly not disappointed in any way. The University boasts a student population of 167,000 and a Chemistry and Chemical Engineering student population of 4,000. I don’t know too many Universities that can claim that kind of impact. The Conference was a great opportunity for students and faculty to present their work, along with a number of industry people I can only hope that the level of commitment, enthusiasm, interest, respect and ambition could be exported to the U.S.; these students were great to be around and I was very impressed.  Mexico has many opportunities to implement greener chemistry and engineering solutions and I am confident that the students are being prepared to accomplish this.


The following week was the annual Roundtable meeting of the Green Chemistry and Commerce Council, in Portland, OR. The GC3 is celebrating their 10th anniversary this year, just like the ACS GCI Pharmaceutical Roundtable. Portland is a great place to have a meeting and I am looking forward to holding the 20th Annual GC&E Conference in Portland next year. The GC3 Roundtable is a different experience than the GC&E Conference since it is limited to about 150 people, and it is a business-to-business oriented meeting. In addition to a variety of speakers and workshops, the GC3 discussed the results of work they had been carrying out on mainstreaming green chemistry and better understanding the business case for green chemistry. This meeting, like many others, impresses upon me the enduring difficulty of implementing green chemistry and engineering solutions across the value chains of the goods and services we all know and use. A disconnect remains between the entrenched interests of the chemical industry and the desires of consumers for the types of chemicals in the products they purchase. I think it is fair to say that there is a considerable amount of innovation that will be required to bridge the current divide.


The ACS GCI Chemical Manufacturers’ Roundtable received great news in early May that their proposal to the National Institute of Science and Technology Advanced Manufacturing Technologies Program was funded. This is a 2-year, $500,000.00 planning grant to develop a roadmap for the development of alternative separations technologies to what is currently the most commonly used separations technology in the chemical processing industries – distillation. Distillation alone accounts for 25% of the energy use in chemical manufacturing, so implementing less energy intensive separations technologies has a strong economic and environmental incentive. The Project Team is looking to parlay the technology roadmap into a sustainable consortium committed to the development and implementation of new technologies.  No small feat in just two years! This project begins June 1 and we are working already to bring the right people together to make this happen. Please do let us know if you have any questions or would like to be a part of this effort.


Last but not least, we are busily preparing for the 19th Annual Green Chemistry and Engineering Conference to be held in

N. Bethesda, MD July 14th through the 16th. The Conference Organizers have been working since last July on this conference and it is shaping up to be another great conference. There are so many activities the entire week, beginning with an NSF sponsored workshop for students and the 20th Annual Presidential Green Chemistry Awards Ceremony on Monday, and ending with an ACS GCI Pharmaceutical Roundtable meeting on Friday. There is so much going on that you simply have to come to be a part of it.  And if you are there, be sure to thank the Technical Program Chairs, the ACS GCI Staff, the sponsors and exhibitors, the ACS GCI Industrial Roundtable members and many others for putting on the best green chemistry event of the year.  I hope to see you there!


As always, please do let me know what you think.




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Imagine taking a simple organism and designing materials and devices, much like nature would, to deliver innovative advancements in energy, the environment, and medicine, including cancer research. That is what Professor Angela Belcher not only dreamed up, but made a reality. The Bimolecular Materials Group at MIT, the Research Group of Professor Angela Belcher, uses directed evolution and engineered organisms to create hybrid organic-inorganic electronic, magnetic, and catalytic materials (MIT Bio). These non-toxic materials have been used in solar cells, batteries, medical diagnostics and for basic single molecule interactions related to disease, “I am a materials chemist and everything is a material to me. What my group is really good at is finding ways of utilizing biology to make nanomaterials or bring together a collection of materials at the nanoscale that could improve device performance,” stated Professor Belcher.


Belcher preferred pic.jpgThe Bimolecular Materials Group uses protein from abalone shells to build a strong structure that can be used to grow energy storage devices (batteries) and solar cells. They take an M13 Bacteriophage, whose job it is to infect bacteria, and force it to latch onto and coat itself with inorganic materials to create a nanowire. Belcher's group coaxed many of these nanowires together and found they resemble one of the basic components of a compact battery (Science Daily).


In an interview with Slate Magazine, Belcher stated, “by inserting a specific gene, we spurred the virus to produce a protein coat that binds with compounds such as cobalt oxides and iron phosphates. The virus is long and tubular, so we were able to grow nanowires with these compounds, which we used in an electrode for a prototype lithium-ion bio-battery.”


The green chemistry and engineering behind this method is rooted in life cycle thinking; i.e., discovering ways to produce a powerful structure and ensure it will have minimal impact. “We try to use low temperature processes, water as a solvent and non-toxic and earth abundant materials. We have spent years learning to scale both the inorganic materials and the biological materials for application of interest. We do not believe that our technologies are scalable for all problems, but we focus on problems that we can have an impact on.”


Belcher explained that currently, the Bimolecular Materials Group is working with energy storage and creating new catalytic materials for applications in energy and therapeutics, “finally, we have a major effort in designing new materials and instrumentation for both image guided surgery and non-invasive imaging in cancer.”


Professor Angela Belcher attended the University of California, Santa Barbara, for her undergraduate and graduate degrees. She received her B.S. in Creative Studies and her Ph.D. in Chemistry. Belcher joined the MIT faculty in 2001 as a professor in the Department of Biological Engineering and Materials Science & Engineering. Her research is focused on biomaterials, biomolecular engineering, energy, nanoscale engineering, and synthetic biology, “I have been inspired my whole career by how nature makes materials. In addition to being able to make materials on the nanoscale, biology makes materials in a way that is compatible with the environment. We are inspired by nature’s approach to manufacturing.”


Belcher will be one of four esteemed keynote speakers at the 19th Annual Green Chemistry & Engineering Conference, in Bethesda, MD., this July 14-16, “I am very excited and honored to present at this meeting. Green chemistry and green approaches to materials and technology is essential to maintain a sustainable society. In addition, I am excited about the level of interest in these fields from our youngest scientists.”




“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.


To read other posts, go to Green Chemistry: The Nexus Blog home.

Do you want to make an impact on issues like climate change, reliance on fossil fuels,  environmental contamination, unsafe chemicals in consumer products, and conflict minerals use?


VOTE for the next wave of innovation that will provide real solutions to these problems through your support of the ACS Green Chemistry Institute’s® 2015 Green Chemistry & Engineering Business Plan Competition.


These pressing global issues are impacted by chemistry, and green chemistry holds the key for addressing these critical environmental, health, and cost concerns. Everyone has a stake in this decision, and YOU can ensure greener products will be one step closer to the market place. This is the only competition of its kind exclusively dedicated to green chemistry and engineering and provides the chance for sustainability-oriented entrepreneurs to move their green innovations to a commercial reality.


This is your chance to help accelerate solutions to some of the world’s biggest challenges like:

  • Dependence on endangered elements in chemical processes
  • Displacing petrochemicals by transforming renewable or waste feedstocks into valuable chemicals
  • Reducing hazardous chemical inputs in products and processes
  • Minimizing energy use and emissions


Click here to cast your vote for the "Change the World with Green Chemistry" campaign!


Sign up by July 10, 2015 to help choose a winner. You will be contacted after you select your level with the voting ballot. 100% of proceeds go to the Grand Prize Winner of the competition.


Meet the 5 semi-finalist teams--follow the links to hear their first round pitches!


Dedicated to the development of bionomic products in the areas of Agriculture, Environmental Remediation, Bio-Industry, and Human Health. (Translation coming soon).



Data-driven software that speed up the development of sustainable chemicals by increasing efficiency of chemical R&D processes. (Live video coming soon).



Genesis Reclaimers advance chemical recycling technology. Automation makes recycling practical in any lab.



Creating a power source from recycled packing peanuts.


Created the Waste Grease Extraction process, the technology that utilizes troublesome substances straight from the waste water facilities, reducing damage to their equipment and the landfill.



The final round of the competition will take place on July 15, 2015 at the 19th Annual Green Chemistry & Engineering Conference. Visit the conference website to learn more and register for this exciting event!




“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.


To read other posts, go to Green Chemistry: The Nexus Blog home.


Surfing into a Green Future

Posted by ACSGCI May 22, 2015

Written by Kim Mcdonald, Biological Sciences, UC San Diego News Center


The world’s first algae-based, sustainable surfboard was produced by UC San Diego biology and chemistry students.

UC San Diego’s efforts to produce innovative and sustainable solutions to the world’s environmental problems have resulted in a partnership with the region’s surfing industry to create the world’s first algae-based, sustainable surfboard.

algae-surfboards-mayor-san-diego.jpgThe surfboard was publicly unveiled and presented Tuesday evening, a day before Earth Day, to San Diego Mayor Kevin Faulconer at San Diego Symphony Hall, where he hosted the premiere of the National Geographic “World’s Smart Cities: San Diego” documentary. The program, which features innovations from UC San Diego, is scheduled to air Saturday, April 25 and May 2 on the National Geographic Channel.


“Our hope is that Mayor Faulconer will put this surfboard in his office so everyone can see how San Diego is a hub not only for innovation, but also for collaboration at many different levels,” said Stephen Mayfield, a professor of biology and algae geneticist at UC San Diego who headed the effort to produce the surfboard. “An algae-based surfboard perfectly fits with the community and our connection with the ocean and surfing.”


Mayfield, an avid surfer for the past 45 years, joined Cardiff professional surfer Rob Machado and Marty Gilchrist of Oceanside-based Arctic Foam, the largest surfboard blank manufacturer in North America, to present the board to Mayor Faulconer.


The project began several months ago at UC San Diego when undergraduate biology students working in Mayfield’s laboratory to produce biofuels from algae joined a group of undergraduate chemistry students to solve a basic chemistry problem: how to make the precursor of the polyurethane foam core of a surfboard from algae oil. Polyurethane surfboards today are made exclusively from petroleum. “Most people don’t realize that petroleum is algae oil,” explained Mayfield. “It’s just fossilized, 300 million to 400 million years old and buried deep in underground.”


Students from the laboratories of Michael Burkart, a professor of chemistry and biochemistry, and Robert “Skip” Pomeroy, a chemistry instructor who helps students recycle waste oil into a biodiesel that powers some UC San Diego buses, first determined how to chemically change the oil obtained from laboratory algae into different kinds of “polyols.” Mixed with a catalyst and silicates in the right proportions, these polyols expand into a foam-like substance that hardens into the polyurethane that forms a surfboard’s core.




To obtain additional high-quality algae oil, Mayfield, who directs UC San Diego’s California Center for Algae Biotechnology, or “Cal-CAB,” called on Solazyme, Inc. The California-based biotech, which produces renewable, sustainable oils and ingredients, supplied a gallon of algae oil to make the world’s first algae-based surfboard blank. After some clever chemistry at UC San Diego, Arctic Foam successfully produced and shaped the surfboard core and glassed it with a coat of fiberglass and renewable resin.


Although the board’s core is made from algae, it is pure white and indistinguishable from most plain petroleum-based surfboards. That’s because the oil from algae, like soybean or safflower oils, is clear. “In the future, we could make the algae surfboards ‘green’ by adding a little color from the green algae to showcase their sustainability,” said Mayfield. “But right now we wanted to make it as close as we could to the real thing.” The algae surfboard not only represents the kind of collaboration that is the hallmark of UC San Diego, but the fusion of biotechnology, surfing and environmentally conscious thinking that has made the La Jolla campus and its environs such a desirable place to work and live for scientists, innovators and those who cherish the coastal environment.


Mayfield said that, like other surfers, he has long been faced with a contradiction: His connection to the pristine ocean environment requires a surfboard made from petroleum. “As surfers, more than any other sport, you are totally connected and immersed in the ocean environment,” he explained. “And yet your connection to that environment is through a piece of plastic made from fossil fuels.

Now surfers can have a way to surf a board that, at least at its core, comes from a sustainable, renewable source." “In the future, we’re thinking about 100 percent of the surfboard being made that way—the fiberglass will come from renewable resources, the resin on the outside will come from a renewable resource,” Mayfield said. “This shows that we can still enjoy the ocean, but do so in an environmentally sustainable way,” he added.


This story is available at: http://ucsdnews.ucsd.edu/feature/surfing_into_a_greener_futur

From the UC San Diego News Center



“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.


To read other posts, go to Green Chemistry: The Nexus Blog home.

Next Phase Kicked-off with Special Issue of Aldrichimica Acta


Company's top-ranked* chemical review journal to feature commentary from thought leaders in green chemistry

Sigma-Aldrich Corporation (Nasdaq: SIAL), a leading life science and high technology company, today launched the next phase of its global green chemistry initiative. The program, which aims to reduce the chemical-related impact on human health and the environment, kicks off with the first-ever "green" issue of the Company's chemical review journal Aldrichimica Acta. Professor Bruce H. Lipshutz, Guest Editor, commented, "This thematic issue of the Acta offers the chemistry community a unique opportunity to gauge the progress, and glimpse into the future direction, of a broad research effort aimed at increasing awareness of the importance of sustainability in the practice of chemistry, and at inventing ways to mitigate the adverse impact of experimental chemistry on the environment." This special issue contains the latest thinking from 15 of the world's foremost experts on green chemistry. The launch of this issue is accompanied by an exciting update of the Company's green website, SigmaAldrich.com/green, which acts as a core information hub, providing a rich source of shareable content on all aspects of green chemistry.

"In curating this latest issue of Aldrichimica Acta, we have combined commentary from the 'fathers' of green chemistry, as well as published articles and cutting-edge research to foster stimulating exchanges, which will inspire further quests in the field," said Dr. Sharbil Firsan, Senior Specialist and Editor of the Aldrichimica Acta. "In our 48-year history, this is one of our most important issues to-date, gathering scientific understanding from the thought leaders who are truly pushing the field forward, with insights that can't be found anywhere else." The continued push toward green chemistry, part of Sigma-Aldrich's more than 10-year commitment to corporate citizenship and sustainability, aligns with a number of the Company's efforts to change the face of science.

In this special issue, readers can find a sampling of the latest news in green chemistry, including trends, academic research and more:

  • The industry's global progress in green chemistry and an academic look at its future direction at companies like Genentech, Amgen and Novartis,
  • Articles written by renowned chemists John C. Warner and Paul T. Anastas, who together developed the Twelve Principles of Green Chemistry in 1991,
  • Green chemistry insights into:  fluorous chemistry; organic synthesis, as well as biocatalysis and biomass conversion, in ionic liquids; and Catalytic C-C Bond Formation and the Hendricksonian Ideal, and
  • The official introduction of  Sigma-Aldrich's "Greener Alternatives Platform," which includes DOZN— an industry first quantitative green chemistry calculator that is based on the 12 principals of green chemistry developed by Anastas and Warner.

"Global Citizenship is in our DNA. For decades, we've operated with the goal of improving the quality of life through science," said Dr. Scott Batcheller, Manager of Chemistry, R&D and Product Management. "Our work in green chemistry is the next iteration of that commitment.  We are enabling our scientists and customers to make discoveries that will move science forward while reducing the impact on the environment."

Sigma-Aldrich has developed a portfolio of products that offer greener alternatives to many chemicals traditionally used in today's research labs.  The green portfolio is the broadest offering currently available on the market and forms an important part of the full product listing of the Company, which is now in excess of 270,000 products. This growing product range of greener chemicals continues to increase the options for the scientific community to reduce the environmental impact of their research. This effort is aligned with the Company's newly designed website, which contains a number of valuable scientific resources, including a greener alternative product icon search that enables chemists to identify and consider greener options via the "Greener Alternatives and Technologies" product lists.

Sigma-Aldrich has previously been recognized for its global citizenship efforts on numerous occasions, this year alone being named to the Dow Jones Sustainability Index and a top 100 Most Sustainable Corporation by the Global 100 Index, as well as receiving prestigious honors for the third consecutive year by The Civic 50 for leadership in social responsibility work in the Materials sector. The Company, which has more than 9,300 employees working in 37 countries, generated $2.79 billion in revenue in 2014, and for many years has invested in Global Citizenship, including green chemistry, as a corporate-wide sustainability initiative. In the period of 2009-2014, Sigma-Aldrich has:

  • Reduced waste by identifying increased beneficial reuse opportunities, resulting in a 16 percent intensity reduction in waste generation,
  • Saved more than two million cubic meters of water by upgrading systems and enhancing manufacturing practices,
  • Achieved a second consecutive year of absolute electricity reduction though energy efficiency investments, and
  • Decreased transportation emissions by shipping more freight by sea, reducing its carbon footprint by almost 2,000 metric tonnes. To learn more about Green Chemistry at Sigma-Aldrich, visit sigmaaldrich.com/green. To receive your complimentary subscription to the Acta, or to access back issues, please visit Aldrich.com/acta.

*Top-ranked: Journal Citation Reports, Science Edition (Thomson Reuters Canada, Ltd.). Sigma-Aldrich is a trademark of Sigma-Aldrich Co. LLC, registered in the US and other countries.

About Sigma-Aldrich: Sigma-Aldrich, a leading Life Science and Technology company focused on enhancing human health and safety, manufactures and distributes 250,000 chemicals, biochemicals and other essential products to more than 1.4 million customers globally in research and applied labs as well as in industrial and commercial markets. With three distinct business units - Research, Applied and SAFC Commercial - Sigma-Aldrich is committed to enabling science to improve the quality of life. The Company operates in 37 countries, has approximately 9,300 employees worldwide and had sales of $2.79 billion in 2014. For more information about Sigma-Aldrich, please visit its website at  www.sigma-aldrich.com.

This story is available at: http://investor.sigmaaldrich.com/releasedetail.cfm?ReleaseID=902708

From Sigma Aldrich




“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.


To read other posts, go to Green Chemistry: The Nexus Blog home.

Contributed by Mingxin Liu, graduate student at McGill University


Oxidation of aldehyde towards carboxylic acid is a very common reaction in organic chemistry. At the same time, it is also an unavoidable element of the bio-metabolic pathway. In cytoplasm, aldehydes are highly efficiently oxidized into the corresponding carboxylic acid under very mild (37oC) conditions, utilizing oxygen as the oxidant and enzyme as catalyst. Although this process has been running in our body every day, in industry and academia, methods to achieve this transformation still remain very scarce due to the fact that most oxidation conditions cannot halt the oxidation at the carboxylic acid stage. As a result, traditional oxidations of aldehydes usually yield a mixture of different oxidation products. Even till now, oxidation of aldehydes still relies on stoichiometric amounts of expensive and hazardous oxidants, and often require organic solvents which are also eco-unfriendly.


Professor Chao-Jun Li and his team at McGill University have been focusing on the study of achieving organic reactions in water for many years. Recently, they addressed the above-mentioned difficulties of achieving aldehyde oxidation by introducing a silver(I)-based homogeneous catalyst. With this catalyst, a wide variety of different aldehydes were successfully transformed into the corresponding carboxylic acids in an extremely high efficiency. The reaction only requires very little or even ppm level of silver catalyst loading, utilizes normal atmospheric oxygen (or oxygen gas) as the sole oxidant, and water as the sole solvent under very mild temperature (50oC). Over 50 examples of different aldehydes, including aliphatic, aromatic, and unsaturated aldehydes with different electronic properties and functionalities, have successfully been oxidized into the corresponding carboxylic acids in excellent to quantitative yields. Chromatography is generally not required in almost all cases. With only 2mg (~360ppm) catalyst loading, the gram scale reaction with benzaldehyde also gave 82% isolated yield, indicating the potential possibility of expanding this methodology to industrial level.


Prof. C.-J. Li's Group will continue to explore the potential applications of the silver(I) catalyst.



“The Nexus Blog” is a sister publication of “The Nexus” newsletter. To sign up for the newsletter, please email gci@acs.org, or if you have an ACS ID, login to your email preferences and select “The Nexus” to subscribe.


To read other posts, go to Green Chemistry: The Nexus Blog home.

Contributed by Jeffrey Brown, Executive Director of Practice Greenhealth


Health care professionals are charged with creating environments that foster quality health care delivery, patient healing and healthy workplaces for staff. For over fifteen years, partner organizations Practice Greenhealth and Health Care Without Harm have worked with thousands of leading hospitals, health care organizations and suppliers to help them take steps to create healthier facilities by making better, more sustainable decisions about the products and services they purchase. The most innovative organizations have adopted an intentional and strategic approach: avoiding products, services, and materials that can have negative impacts on patients, staff, our communities and the environment. In doing this, they’ve aligned their operations with health care’s healing mission. We’ve seen lots of progress since our founding, and 2014 in particular was important, as hospitals across the country took a big step forward in selecting furniture and materials that contain fewer or no toxic chemicals.


Creating Healthier Healing Environments


Every day, we are surrounded by thousands of products made from chemicals in our homes, workplaces, schools and stores. Hospitals and health care facilities are no exception.


Forward-thinking health care facilities are zeroing in on furnishings as another important step toward creating healthier healing environments. In fact, the 2013 Healthier Hospitals Initiative Milestone Report released by Practice Greenhealth showed that health care facility spending is up on products that are leading to a healthier healing environment for patients, staff and visitors who walk through the doors.


Practice Greenhealth is working with health care providers to identify chemicals commonly found in furniture that may be hazardous to human health and the environment.


Fortunately, manufacturers have found that it is possible to make healthcare products and furnishings for hospitals using chemicals that we believe are less hazardous, or in many cases, have no known human or environmental toxicity.  We believe that these innovations in product manufacture are a win-win for the companies and more importantly, for people who are healing.


A Game Changer: For the Health Care Sector and the Supply Chain


Last year was a big year in our quest to create healthier healing environments. Early in 2014, the State of California overhauled its 39-year-old flammability rule, allowing furniture manufacturers to meet safety standards without adding hazardous flame-retardant chemicals to foam or fabric used in furniture.


Following the California decision, Kaiser Permanente announced that it would no longer purchase any furniture treated with toxic flame retardants. In September, Advocate Health Care, Beaumont Health System, Hackensack University Medical Center, and University Hospitals Health System followed suit, announcing that they too would transition away from toxic chemicals commonly found in furniture. The five health systems spend roughly $80 million a year to furnish hospitals, medical offices and other buildings with chairs, benches, sofas and other furniture.


Their decision to purchase flame retardant-free furnishings is a game-changer for the health care sector and the health care supply chain.


How to Adopt Safer Purchasing Strategies


Practice Greenhealth has already helped hundreds of hospitals across the country take a big step forward in selecting furniture and materials to create a healthier healing environment. As part of the Greening the Supply Chain® Initiative, we created a supplier directory of Practice Greenhealth business members to assist hospitals with what we feel are better purchasing decisions. The directory is a great source of information on what we consider to be environmentally preferable products and services.




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Contributed by Anne Marteel-Parrish Associate Professor of Chemistry and Chair Frank J. Creegan Chair in Green Chemistry Washington College, Chestertown, MD


I am delighted to share my perspective about what I gained as a regular attendee, participant, and now leader at the Annual Green Chemistry and Engineering conference.


I attended my first conference in 2001, which was the 5th annual Green Chemistry and Engineering conference. It is hard to believe that this year we will be celebrating the 19th conference of this type. I still remembered this first time, not because it was my first time attending a conference, but because it was the first time I was given the opportunity to contribute an oral presentation as a second-year graduate student. I remember how nervous and mortified I was to answer questions from a group of experts.


This conference is my favorite one to attend for the following reasons:


1) I am surrounded by people who have the same passion as I do: Green and sustainable chemistry (it always makes me feel like a student at a large university when I attend a huge meeting where there is a rare chance I will bump into somebody I know…)


2) The meeting place and number of attendees is not too large so I am not lost in a sea of people going from one room to another.


3) The breadth and depth of topics provides the right amount of knowledge for anybody who is either a “newbie” in the field or more of an expert.


4) The ideas exchanged go a long way. I always come home with a plethora of new concepts to implement in my Green and Sustainable Chemistry course or in my research projects.


5) I am excited to bring my own undergraduate students to this conference and share this memorable moment with them.


What I will always remember from this conference is the relationships and friendships forged and renewed during this conference. The connections I made at this conference are sustainable ones! I am always excited to go because this conference helps me learn beyond expectations. I come back rejuvenated, ready to use my critical thinking skills, and apply some of the top-notch principles I learned.


Moreover it was my privilege to lead a technical session titled “Green chemistry beyond the bachelor’s degree (and Ph.D.); Green chemistry education" at the 18th Annual Green Chemistry and Engineering Conference last year in Bethesda, MD. I am very grateful for this opportunity. I can’t wait to attend the next conference as a speaker, session leader, or simply to accompany the next leaders of tomorrow: my students. Go green!



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Universities can be a major resource for industrial innovation, especially when the two collaborate to generate new knowledge and impact. Engaging with academia is key to the strategy of the ACS Green Chemistry Institute’s Pharmaceutical Roundtable. Year after year, the Roundtable delivers on this priority by providing grants for academic-industrial research collaborations ($1.5 million since 2005) and hosting events that act as a bridge between university research and company application. To kick off their 10-year anniversary celebrations, the Roundtable hosted an all-day catalysis symposium in conjunction with their Spring Meeting in Basel, Switzerland.


Roland Thieme, the Head of Chemical Development and Supply at F. Hoffmann-La Roche (the co-host of the symposium), and Juan Colberg, Senior Director at Pfizer and co-chair of the Roundtable, opened the symposium. Their introduction illustrated how the title of the event, “Green Chemistry Makes a Difference: Innovations leading to a more sustainable pharmaceutical industry,” summarizes the mission of the Roundtable—to catalyze the implementation of green chemistry and engineering in the global pharmaceutical industry. For 10 years, the Roundtable has executed on this mission based on their strategic priorities (to inform and influence the research agenda, provide tools for innovation, act as an education resource, and collaborate globally) and, since 2007, a set of key research areas. These research areas are topics that all companies were consistently encountering and seeking greener alternatives for. They were determined via a brainstorming and voting process by the Roundtable, which resulted in three categories the group would target for the next eight years in their initiatives: reactions currently used but better reagents preferred, more aspirational reactions, and solvent themes.


A theme that persists throughout most of these key research areas is catalysis, a fundamental pillar of green chemistry. The Roundtable seeks to not only further employ catalyst technologies in pharmaceutical science, but ensure that the approaches are greener than what currently exist (such as moving away from use of precious metal catalysts). With the goal of triggering innovation in approaches to and applications of catalysis technologies, the symposium in Basel featured six professors based in Europe who are leaders in the field and hosted nearly 20 posters from students, academics, and industry professionals.


Basel Symposium.jpgSymposium speakers from left to right: Marc Taillefer, Uwe Bronscheuer, Katalin Barta, Benjamin List, Janine Cossy, and Michael North.


“The Roundtable convenes events like this symposium to foster discussion between academic and private sector around potential greener commercial approaches, by influencing the new technology research agendas. We are very excited to host these distinguished speakers, as each address important and innovative approaches to make organo, enzymatic, and transition metal catalysis in pharmaceutical science more sustainable. These professors are discussing some of the biggest problems facing the industry with respect to catalysis such as limited supply, toxicity, cost, and solvent volume. One example is the strides made around minimizing the use of precious metals by looking to more sustainable options like iron, nickel and copper--metals that are obtained via cleaner mining processes and provide lower supply risk from more stable mining conditions. Additionally, catalytic methods to access renewable raw materials from biomass were highlighted, establishing sustainable alternatives to petroleum products needed to make life-saving medicines” said the Roundtable co-chairs.


The first talk was from Professor Benjamin List of the Max Planck Institute—Mülheim (Germany), who discussed an approach to enantioselective synthesis called “asymmetric counteranion directed catalysis.” This technique can be applied to several reactions (such as alylation, phosphylation, etc.), many of which are frequently employed by the pharmaceutical industry. List was followed by Professor Katalin Barta of University of Gronigen (Netherlands). She focused on strategies for the conversion of biorenewables through sustainable catalysis with earth abundant metals. The approaches Barta presented not only provide catalytic innovations for the industry, but will lead to renewable-based (rather than petroleum) starting materials the industry depends on everyday as reagents and solvents. Professor Marc Taillefer of ENSC Montpellier (France) wrapped up the first half of talks with his work, which utilizes copper and iron catalysts that allow for a wide range of transformations (achieving C-C, C-O, and C-N bonds) under significantly milder conditions than traditional approaches.


Between the talks and during meals throughout the day, attendees were able to peruse the poster session highlighting work ranging from one-pot cascade reactions to ball-milling as a solventless reaction. “I genuinely believe that society cannot continue at current consumption levels, and as chemists we can address this by moving towards new, sustainable approaches, such as batch to flow processes. This symposium has brought together a lot of people from many companies, yet is small enough so that everyone can talk to everyone and discuss real-world problems and solutions,“ said G. Kemeling, the Editor in Chief of ChemSusChem.


After lunch, the symposium attendees flowed back into the auditorium to hear Professor Uwe Bornscheur of University of Greifswald (Germany) discuss enzyme discovery, engineering, and application in biocatalysis. Bornscheur walked the audience through the history of how enzymatic processes have been able to replace chemical routes, and used his work to show a broad range of enzyme-catalyzed reactions that are efficient, highly selective, and can be achieved under mild conditions with less by-products than equivalent chemical routes. Professor Janine Cossy of ESPCI Paris (France) followed with a talk filled with approaches to cyclization and coupling that replace palladium catalysts with a variety of alternative and greener catalysts (such as the more abundant iron). The molecules she focuses on (macrocyclic) are currently under-exploited by industry (accounting for only 2% of orally available molecules on the market, currently useful for anti-tumoral activity), but her work can deliver steps to these molecules with more benign chemistry. The symposium closed with Professor Micheal North from University of York and the Green Chemistry Centre for Excellence (England). His talk highlighted his group's bimetallic catalytic approach that allows for transformation of carbon dioxide to cyclic carbonates, as well as applications of these carbonates as green solvents. By making use of waste CO2 and moving towards flow chemistry, the research is delivering ethylene carbonate and propylene carbonate as possible solvent replacements for DMF, DMSO, and other toxic media sometimes present in pharmaceutical science. Another emphasis of North's talk was the importance of outreach, to both student groups and industry, which the Centre incorporates into each of their project areas.


John Tucker, a senior scientist at Amgen and co-chair of the Roundtable, closed the day's events with a summary of how these talks had already instigated much inspiration and conversation for future innovation. Whether it was the elegant cascade reactions facilitated by enzymes or the replacement of unsustainable metal catalysts, the symposium offered a wide array of technologies that have the potential to transform the industry. As the Roundtable looks to their next ten years they aspire to continue delivering on their strategic priorities, and bridge academic and industrial communities throughout the world to make their science more sustainable. The 10-year anniversary celebrations will continue throughout the year, with the next events taking place at the 19th Annual Green Chemistry and Engineering Conference in the Washington, DC area (USA) and the 250th ACS National Meeting and Exposition in Boston, MA (USA). The Roundtable will also be releasing an update of their key research areas, discussing new focus areas, as well as actions and progress to date. For more information, please visit the Pharmaceutical Roundtable’s website and for Roundtable updates and announcements, follow ACS GCI on social media (Twitter, Facebook, and LinkedIn).


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Message from the Director

Posted by ACSGCI Apr 22, 2015

Contributed by David Constable, Director, ACS Green Chemistry Institute®


There is always a lot going on in green chemistry and engineering, which is a great thing. I sometimes hear that many people don’t think that is the case and believe that more should be done and at a faster pace. But, from where I sit, there is a lot going on and green chemistry is being discussed and implemented more and more with each passing day.


Just take the ACS National Meeting as one example. For anyone who hasn’t been to an ACS national meeting, you should try and go at least once to experience the breadth and depth of the meeting. On any given day, several technical divisions are sponsoring sessions on some aspect of chemistry that falls under the umbrella of sustainable or green chemistry and engineering principles. These sessions aren’t always labeled as sustainable or green chemistry or engineering, but a quick look at what is being presented should demonstrate that there’s a lot to offer in these areas. To be clear, what is being presented isn’t always about toxics elimination either (actually, it usually isn’t) and the presenters may not actually consider what they are doing to be sustainable or green chemistry and engineering, but that doesn’t mean it isn’t. The bottom line for me is that I’m greatly encouraged to see all the programing that is available at the ACS National meetings and I hope that it continues.


Another major event for the ACS GCI that is not terribly apparent to anyone outside of the Institute, is our twice a year Board meeting. For those who are unfamiliar with the ACS and how it operates, there are many governance structures to oversee the work of the ACS, and one of those is the ACS GCI Board. For a complete list of who is on the ACS GCI Board click here. The Board is responsible for overseeing the work of the ACS GCI, sets its strategic direction, and discusses what it thinks we should be doing. We had a good meeting in early April and some excellent discussions on several projects, partnerships and alliances with other green chemistry organizations, and how best to proceed in a world of ever-increasing green chemistry and engineering organizations.


The same week of the Board meeting the Organizing Committee for the Green Chemistry and Engineering Conference met to finalize the technical program for the 2015 conference scheduled for July. The Conference is shaping up to be another great year with solid technical programming thanks to the hard work of the organizing committee and their session chairs. Many don’t realize that the Organizing committee has been at work since last summer and very engaged in making the conference a reality. For those of you that had not heard elsewhere, we were greatly saddened by Dr. Richard Wool’s untimely passing in late March. Richard had been such a strong force in green chemistry and engineering for a long time and was very active and committed to making the conference a great event this year. We will miss him greatly, but we were pleased to welcome to the organizing committee a former student of Richard’s, Dr. Joseph F. Stanzione, a professor at Rowan University, to take up where Richard left off. Finally,


I’d like to acknowledge the ACS GCI Pharmaceutical Roundtable's successful meeting in Basel, Switzerland, the week of 13 April. For those of you that don’t know, the Pharma RT is celebrating its tenth year anniversary  and in addition to their normal meeting, they had a great one-day symposium on green chemistry to help them celebrate. The ACS GCI Pharma RT continues to make a number of significant contributions to green chemistry and engineering, and I look forward to their continuing success over the next ten years.


So, I’ll end as I began; there’s a lot going on in green chemistry and engineering, and while it may not be apparent to everyone, it’s undoubtedly a good thing. As always, please do let me know what you think.




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Although there is no official government ranking of which city is the most sustainable city in the United States, a constant contender on the numerous amateur lists has been Portland, Oregon.


According to the International Business Times, some of the factors involved in being considered a sustainable city are the size of the city’s “carbon footprint”, number of certified buildings designed with minimal nonrenewable energy use, reduced water consumption, and cities with high proportions of green space. Travel and Leisure dubbed Portland the number one greenest city in America in 2015, “for its mass transit and near the top for its groovy, offbeat locals, known for their DIY spirit and cycling culture.”


877440523_83256c2402.jpgThe Portland Bureau of Planning and Sustainability (BPS) , “develops creative and practical solutions to enhance Portland’s livability, preserve distinctive places and plan for a resilient future”. They list the numerous ways the city strives to be more sustainable, such as having green buildings—a way of designing and constructing buildings to increase performance and enhance the health and experience for people who work, live and play in these structures. The city saves water and energy, generates low carbon emissions, uses renewable energy and more.


Jennifer Allen, associate professor of public administration and director of the Institute for Sustainable Solutions (ISS) at Portland State University, stated “They [BPS] lead the development and implementation of our Climate Action Plan – Portland was the first city in the U.S. to have such a plan, and BPS does a great job of engaging all the relevant partners in exploring how we can meet the goals of the plan.”


Allen has worked in the field of sustainable development since 1987, and first began working at the World Bank on efforts to better integrate environmental and social considerations into international development. Her stance on sustainable cities starts with the understanding of how people make choices every day, and ways to encourage valuing and conserving their resources.  “We need engineers, urban planners and other design thinkers to bring innovative strategies to the table to enable us to get around with a smaller environmental footprint, and to reframe topics such as infrastructure development to better integrate natural systems. Taking a more integrated approach to planning and development is a critical step. For example, Portland seeks to promote ‘20 minute neighborhoods’ that allow residents to access the basic services they need without traveling long distances,” Allen stated.


Now, you’re probably thinking, “why are you highlighting the city of Portland when there are multiple cities making every effort to be more sustainable?” Well, dear reader, since this month’s issue of The Nexus e-newsletter is themed Sustainable Cities, we wanted to take this moment to announce that the 20th Annual Green Chemistry & Engineering Conference (GC&E), to be held in 2016, will be hosted in Portland, Oregon.


Jennifer MacKellar, the ACS Green Chemistry Institute® Program Manager, stated that hosting GC&E 2016 in Portland is “an exciting opportunity to engage new audiences, revitalize the content and leverage our west coast partners. There is a lot happening in the green chemistry/sustainability space in the Portland and the west coast area that we can highlight through our technical sessions.”


The conference will be held at the Portland Hilton & Executive Tower, which has several green practices, including a robust recycling program, food composting, energy efficiency, water conservation, waste minimization and using greener products. They also try to locally source their food as much as possible, “these were important factors for us when choosing a meeting location”, stated MacKellar. There are several companies that support green chemistry in the Portland area. Nike in particular, has been a huge supporter of green chemistry and has worked very hard to include green chemistry into their corporate practices. There are also several universities in the region that have strong green chemistry programs, including University of Oregon, Oregon State, UC Berkeley, and Portland State University. Offering our 2016 conference in the Portland area will give enthusiastic green chemistry students a great opportunity to attend without the high travel costs.


Portland is just one of many sustainable cities, not only in the country, but the world! ACS GCI is excited to continue the planning for the 20th GC&E Conference and we hope to see you in Portland in 2016!




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Contributed by Douglas Fox, Department of Chemistry, American University, Washington, DC


Our research group helps to improve the sustainability of buildings and cities by focusing on the development of affordable and effective flame retardants that are synthesized from natural products. These flame retardants are blended with plastics or formulated into a coating for use in flexible foams and wood based products. Some have been used in bio-derived plastics to reduce their flammability without the typical degradation of desirable polymer properties, thereby increasing the number of commercial applications for these types of plastics.


Plastics, polymers, and polymer composites have become ubiquitous over the past 60 years. In 2013, nearly 300 million metric tons of plastic were produced, making it one of the most used materials worldwide on a volume basis. Their increased use can be traced to their inherent properties: strong, lightweight, flexible, moldable, and inexpensive.  In addition, it is relatively easy to incorporate additives to tune their properties. These composites can be tailored to achieve desired properties on opposite ends of the spectrum by simply mixing molten polymer and filler using an extruder.


For example, addition of glass, carbon, or natural fibers increase strength and stiffness. Addition of a plasticizer decreases tensile strength and softens the composite. Addition of clay can reduce diffusion of gases or solvents, whereas incorporation of water soluble salts during extrusion can increase voids in the processed plastic. Or, the addition of benzophenones aids used to protect the polymer from photodegradation, while the addition of titanium dioxide can be used as a photoinitiator to accelerate UV degradation of the polymer.  But plastics also come with a range of disadvantages, presenting major challenges. They are inherently flammable, increasing the risk and costs of fire.  Most of the monomers, or building blocks of the polymer, and many of the fillers used to tailor the properties, are toxic, bioaccumulative, or persistent chemicals, posing many health concerns, both real and perceived. And, they are generally durable. Combined with their low densities (lightweight), this generates a major waste management issue. Recycling has alleviated some of the waste burden, but plastics still represent over 20% of the waste in landfills, and over 5 million tons of plastic finds its way in oceans every year.


Nexus picture.jpgOne of the more difficult disadvantages to address is the high flammability of plastics. In the United States, fires account for over 3,000 deaths, 16,000 injuries, and $11 billion in property loss every year. This represents a major decline over the past few decades. Part of this reduction can be attributed to the use of flame retardants in residential upholstered furniture, which reduce the toxicity of combustion products and allow for longer egress times during fires. Fires can be started by either open flame sources, such as candles or matches, or by smoldering sources, such as cigarettes or incense. There are many methods that can be used to address these problems, such as use of smolder resistant fabrics, back-coating fabrics, or the addition of flame retardants. Recently, there has been increasing concern over the migration, persistence, potential toxicity, and perceived lack of efficacy of flame retardants typically used in furniture and flexible foam. This has led to public debate, regulation changes, and increased pressure to find alternatives. The alternatives include both approaches to reducing fire risks as well as development of safer, less transient, more efficient flame retardants.


The largest concern of the increased use of plastics is probably the problems associated with their disposal. There is an increased public awareness of the growing risks associated with waste, pollution and the need for more sustainable products and practices.  The most widely used plastics are synthesized from petroleum distillates, generating a resource and energy sustainability issue.  These plastics do not biodegrade, but will photodegrade into smaller fragments. This leads to the leaching of the starting materials and fillers used in the production of the composites, many of which are toxic to plants and animals alike. In addition, the small photodegraded plastic fragments are consumed by animals in the wild, which are also toxic or disruptive to their life cycle. This persistence, bio-accumulation, and toxicity of leached chemicals leads to a loss in biodiversity, which can affect the sustainability of entire ecosystems. Resolving this issue is quite complex due to technical, societal, economic, and logistical issues. Attempts have been made to produce biodegradable plastics and/or plastics from bio-derived sources, such as starch based plastics, soybean based epoxies, and corn based poly(lactic acid). Unfortunately, these plastics possess properties that are inferior to their petroleum based counterparts and often cost much more to produce. There are a large number of scientists and engineers working on addressing these issues, and much progress has been made. With the addition of select additives and cheaper production practices, these bio-based and biodegradable plastics have slowly been making their way into the marketplace. Much of their use today has been limited to plastic utensils and packaging applications, but their blends with more traditional petroleum based plastics have also been explored for use in textiles and electrical equipment.


We are addressing these issues by developing more sustainable polymer nanocomposites with improved flame resistance and better compatibility between the filler and polymer. These composites would be used primarily in the home or businesses, helping to develop more sustainable cities. We have two primary goals in our work:


  1. The use of fillers and crosslinkers to improve the water resistance and mechanical properties of bio-derived polymers.
  2. The modification of natural materials to improve both interfacial adhesion and flame retardant properties of the polymer.


In many of our systems, we have addressed issues in both of these areas simultaneously.


Our primary focus is currently on the development of flame retardants using natural materials. We began with using cellulose as a replacement for one of the components in an intumescing flame retardant. An intumescing flame retardant produces a foaming char barrier through the use of a dehydration source (typically an acid), a carbon source (such as pentaerythritol), and a gas forming source (typically a polyamine). The use of cellulose fibers is more sustainable than traditional carbon sources used in intumescing flame retardants and can improve mechanical strength and stiffness if there is good interfacial adhesion with the polymer. To increase the amount and mechanical durability of the char during combustion, we utilized silicon containing materials. The modification of cellulose using a reactive POSS molecule (POSS is a hybrid between silica (SiO2) and silicone (R2SiO) that can be attached directly to polymer chains) was effective for flame retarding poly(lactic acid) while preventing the hydrolytic decomposition of the polymer during processing and preventing the loss in mechanical properties that typically accompanies this hydrolytic decomposition. The addition of organically modified clay was only partially effective due to the inability to fully separate the clay layers during processing.


Intumescing flame retardants suffer from the need for multiple components with variable surface energies and morphologies as well as moisture sensitivity, leading to the leaching of flame retardant during weathering and poor interfacial adhesion with some polymers. We are examining methods to utilize cellulose fibers for an all-fiber intumescent.  We phosphorylated the POSS modified cellulose to add the acid source needed to promote char. The level of phosphorylation was insufficient to replace typical acids, but the improvements observed were encouraging for future studies.  We recognized that starting with cellulose nanocrystals (CNCs), which have greater reinforcing potential, may be more advantageous than using cellulose fibers. CNCs that are produced from oxyanionic acids (like sulfuric acid) participate in side esterification reactions with the oxyanion. Use of sulfuric or phosphoric acid would produce CNCs that contain acidic sulfur or phosphorus groups, both of which are typically good flame retardants.  We have experimentally determined that sulfuric acid produced CNCs have a lower thermal stability but better flammability characteristics than unmodified cellulose fibrils. We are currently developing modification methods to simultaneously increase the thermal stability of the CNCs and modify the surface energy to improve interfacial adhesion with hydrophobic polymers.


It is difficult to homogenously disperse cellulose fibers or crystals in epoxy thermosets. Most epoxies are quite hydrophobic (poor interfacial adhesion), have high viscosities (mixing difficulties), and take hours to cure (time for suspensions to settle). For these systems, we examined the use of lignosulfonate and tartaric acid as an intumescing flame retardant. Lignosulfonate, which is a by-product of the sulfite pulping process, was very effective as a flame retardant for epoxy composites, but it had a tendency to migrate to the surface during curing.  As a result, the protective layer that forms can crack and peel off the surface when exposed to a radiant heat sources for too long.  We are currently investigating methods to prevent this migration during epoxy curing.


The largest fuel source in a home is upholstered furniture. To reduce the fire risks associated with them, the foam had been required to pass both smoldering and open flame fire tests. Manufacturers typically used brominated flame retardants to pass the open flame tests. Due to increasing concern over the persistence, potential toxicity, and perceived ineffectiveness of these flame retardants, industry has renewed interest in flame retardant alternatives. The newest regulations for upholstered furniture does not require an open-flame test, but that does not eliminate the risks associated with these type of fires nor guarantee that they will not be re-established. As a result, there is still an urgent need to develop more environmentally benign flame retardants for upholstered furniture or flexible foam.  In light of these developments, we have been developing flame retardant coatings using natural materials.  We use borate salts (which have been used extensively in wood as anti-fungal agents), phytic acid (which is a phosphate storage molecule in plants), or taurine as the primary flame retardant. To keep the flame retardant from washing away, we use carbohydrates, polydopamine, or food proteins as binding agents. Other natural additives to add char strength, anti-fungal properties, smoldering resistance, or binder crosslinking are currently under investigation.


As we design our approaches, we remind ourselves of the need to maintain processability. This includes both process design as well as operating costs.  It is my belief that great studies in sustainable materials and chemistry will not actually improve sustainability unless industry and commercial enterprises are able to technically and economically adopt the process. We welcome additional input from engineers, managers, and industry, especially on optimizing processing techniques, to help us achieve useful, ecologically sustainable products commonly found in homes and cities.




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