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Finding Sustainable Ways To Create and Destroy Plastics

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Despite the society-changing improvements that plastic materials have brought to humanity, there’s no question that they also present us with new challenges regarding what to do with the large amounts of plastic waste we generate, from the oil-based chemicals used to create products to the microplastics found everywhere after plastics breakdown in the environment.

Finding a solution to plastics pollution that will work in the lab and in the real world will take a diverse team of innovative individuals with expertise that transcends the incredible talent found at the University of Delaware. That’s why researchers from UD’s College of Engineering and Joseph R. Biden, Jr. School of Public Policy and Administration are joining forces with experts at the University of Kansas and Pittsburg State University.

“The practices by which society works now are really not sustainable,” said Raul Lobo, Claire D. LeClaire Professor of Chemical Engineering and associate department chair in UD’s Department of Chemical and Biomolecular Engineering, who is leading the research effort for UD. “We need materials that minimize our dependency on fossil fuels and that allow consumers to recycle plastic products efficiently and with ease.To this end, the UD-KU team will develop new molecules that can be used to make a new generation of environmentally friendly plastics.”

The National Science Foundation’s Experimental Program to Stimulate Competitive Research has awarded the group $4 million in funding to do just that. About $1.4 million of that funding will go to UD to support this vast research effort to develop processes to transform “biomass,” such as agricultural byproducts, into commercially viable plastics materials and to chemically deconstruct such plastics effectively and efficiently so that they can be recycled and reused.

UD faculty members on the team include Professor Hui Fang with the Department of Electrical and Computer Engineering, Professor Kalim Shah with the Biden School and Department of Chemical and Biomolecular Engineering Professors Marianthi Ierapetritou, Lobo, Marat Orazov and Dionisios Vlachos.

Lobo, who also holds a joint professorship in the Department of Materials Science and Engineering, said the project will focus on developing polymers that behave like polyethylene terephthalate, or PET, a very common type of plastic found in consumer products such as water bottles, fleece and food-wrapping film. A polymer is a very long molecule, such as proteins, starch or DNA, that is built of repeated building units, like the adenine (A), guanine (G), cytosine (C) and thymine (T) in DNA molecules. Different polymers form by knitting together different building units. Once they are sufficiently long, they can be easily melted, shaped or molded, and solidify upon cooling

“We have ideas of polymers we think will make materials that are better than PET in a number of ways,” Lobo hinted. “Now, we have to prove it.”

From Biomass to Building Blocks

The goal is not only to find new materials with good and useful properties, but to do so using molecules with building blocks that come from biomass (and not fossil fuels like oil) and that are designed to be recyclable.

“We’re trying to make this society more sustainable by developing technology that has the potential to be practical,” Lobo said. “The material we’re trying to make … looks like the plastics we use today, but comes from biomass.”

For example, plants also produce sugars with fewer carbons than the sugar that we eat, and those sugars and their derivatives could be used as building blocks for plastics. The material has to be stable just enough, and strong enough, to hold up in another life as, say, a plastic bag. By focusing on biomass that’s not edible and not toxic — think of stalks from corn or leftover parts from harvested sugar cane — researchers will try to prepare new building blocks for plastics such that they don't compete with food sources, do not depend on fossil fuels and can be easily assembled and reassembled.

Then these engineers must figure out how to translate the science into actual societal benefit. That means also exploring the policy and economic elements associated with shifting the foundational building blocks of a product used in almost everything in our daily lives.

The practical implications of this work will certainly relate to cost. Six decades of experience making PET and using it in multiple products means six decades of being able to find cost efficiencies along the way. It will still take some time for any new building blocks that could replace PET, even if they are superior in performance and for the environment, to find all possible efficiencies and cost savings. 

Over the next four years, up to five UD graduate students will play a role in this interdisciplinary research, from the machine learning that will be used to explore existing research literature and gaps in knowledge, to the chemistry of the components, to the economics of their application and recycling.

“There’s a vast amount of information there,” said Hui Fang, an associate professor with the Department of Electrical and Computer Engineering. “We’re trying to develop a machine learning-based technique that can first extract information automatically from the literature and then allow the researchers to see what’s missing.”

From Wastefulness to Sustainability

With so much waste in the world — up to one-third of the food resources produced are actually wasted — it would be incredibly beneficial to find ways to reuse those tossed corn husks or the leftover fibers from sugar cane, particularly as we try to avoid 1.5 degrees Celsius of atmospheric warming due to greenhouse gas emissions. At the United Nations Climate Change Conference in Glasgow, experts emphasized that exceeding that level of warming will not only be catastrophic, but will be impossible if world nations cannot curb their reliance on fossil fuels.

The idea of a “circular economy,” in which products are produced, consumed and reused — as opposed to the “linear” way the world currently produces, consumes and trashes most products — could literally be that change the world needs. From the molecular beginnings of plastic products, energy is used and waste created. But is it possible to reduce this amount of energy and could the waste be reused in another production process?

“We’re thinking about how we can take the waste stream and make new building blocks,” said Dionisios Vlachos, Unidel Dan Rich Chair in Energy Professor of Chemical and Biomolecular Engineering, director of the Catalysis Center for Energy Innovation and director of the Delaware Energy Institute. “This is a global issue.”

Today, most plastics (and many of the other products we consume daily) are created from petrochemicals. Most plastics are not easily recycled because once they’re broken down into their original pieces, they are difficult to put back together again and so they ultimately end up as waste. UD’s investigators are in pursuit of novel chemicals that can be easily manufactured from biomass and that not only make outstanding plastics, but also could, with little effort, be transformed into raw materials for new plastic products.

“If we don’t take action today, things will be really bad in the future,” Vlachos said. “There are many waste streams with multiple societal health problems. They have to be addressed at a global scale. If we’re making renewable plastics, it would be great, but it’s just part of the story.”

A Holistic View

While some on the team will focus on the chemical engineering of the molecules themselves, Ierapetritou and her team will be analyzing those new materials for their potential environmental impacts, economic costs and whether the new product would be practically scalable from a small lab to a commercialized solution.

In this project, Bob and Jane Gore Centennial Chair of Chemical and Biomolecular Engineering Marianthi Ierapetritou and her team will be analyze proposed new materials for biorenewable plastics for potential environmental impacts, economic costs and feasibility.

“Of course, this goes back to changing the culture of people or introducing different policies, which is one of the things we’re hoping to investigate,” said Ierapetritou, who is the Bob and Jane Gore Centennial Chair of Chemical and Biomolecular Engineering at UD. “But you need policies, you need incentives to make the change that needs to be made.”

What they’re aiming to create may be expensive — possibly too expensive to compete without incentives. But even if some of the new material was used in plastics production, it could still help reduce the pollution associated with creating a product made with 5% or 10% biomass-sourced plastic, said Lobo.

“Our scientific and engineering folks say they can do this in the lab, and they can scale it up. But where is the acceptance or adoption of it?” said Shah, who will be exploring the economic and environmental implications of a substitute for plastics and its potential in real-world markets.

“I think there’s a real awareness now of linking the disciplines that we’re very well known for at UD — chemistry and chemical engineering — to the policy and macroeconomic business aspects of the problem,” he said. “I’m really happy to have colleagues that are willing to include my perspective and take a multidisciplinary approach to us to move forward together.”

If they find the solutions they believe exist, it would still take years before a plant capable of making thousands of tons of polymers goes online. The biomass-sourced building blocks could also be a boon for farmers and companies that work with the agricultural products that could become future plastics.

There’s also the potential they could create something even better: a biosourced plastic that can last longer or require less material.

Their work will also closely examine how to deconstruct these new polymers so that it can be a truly recyclable product. Lobo said he had no doubt they could succeed on that front. But whatever they uncover, they will publicize their findings and make them available to other researchers.

“If we succeed, we might be able to reduce, to some degree, the quantity of plastics or the amount of oil we consume,” Lobo said. “There are chemical reasons why some polymers have these good properties but others don’t. Based on that information, we’re going to eventually be able to provide better products for society. That’s what engineers do.”

This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source.