New Low-temperature Polyethylene Upcycling Method for Waste Reduction

 UC Santa Barbara researchers have developed a one-pot, low-temperature catalytic method that upcycles polyethylene — a polymer that is found in about a third of all plastics produced, with a global value of about $200 billion annually — into high-value alkylaromatic molecules that are the basis of many industrial chemicals and consumer products. Adding value to what would otherwise become trash could make plastic waste recycling a more attractive and practical pursuit with an environmentally beneficial outcome.

New Direction for Plastic Waste

This method represents a new direction in the lifecycle of plastics, one in which waste polymers could become valuable raw materials instead of winding up in landfills, or worse, in waterways and other sensitive habitats.

“This is an example of having a second use, where we could make these raw materials more efficiently and with better environmental impact than making them from petroleum,” fellow chemistry and chemical engineering professor Mahdi Abu-Omar said. Research must still be conducted to see where and how this technology would be most effective, but it’s one strategy that could help mitigate the accumulation of plastic waste, recoup their value and perhaps reduce our dependency on the petroleum that plastics come from.

“We dig a hole in the ground, we produce, we make, we use, we throw away,” Abu-Omar said. “So, in a way, this is really breaking that way of thinking. There’s interesting science to be done here that will lead us into new discoveries, new paradigms and new ways of doing chemistry.”

Chemically Inert Plastics for Multiple Use

The property that makes plastics so useful is also what makes them so persistent. It’s their chemical inertness — they generally don’t react to other components of their environment. Plastic pipes don’t rust or leach into the water supply, plastic bottles can store caustic chemicals, plastic coatings can resist high temperatures.

“There are many positive things about plastics that we have to keep in view,” said Susannah Scott, a professor of chemistry and of chemical engineering at UC Santa Barbara. “At the same time, we realize that there is this really serious end-of-life issue which is an unintended consequence.”

“You can put one of these pipes in the ground and a hundred years later you can dig it up and it’s exactly the same pipe and it keeps your water completely safe,” Scott said. But this quality of inertness also makes plastics very slow to break down naturally and very energy intensive to do so artificially.

New Process with Low-energy Footprint

“They’re made with carbon-carbon, and carbon-hydrogen bonds, and they’re very difficult to chemically recycle,” explained Abu-Omar. Though much research effort has been spent on learning how to reduce plastics to their basic components for sustainability purposes, the energy cost “has plagued the field for a long time”. Even the benefit of converting these building blocks into high-value molecules is limited when it’s cheaper to do the same from extracted petroleum.

“On the other hand, if we could directly convert the polymers to these higher-value molecules and completely cut out the high-energy step of going back to these building block molecules, then we have a high-value process with a low energy footprint,” Scott said.

That innovative line of thinking produced a new tandem catalytic method that not only creates high-value alkylaromatic molecules directly from waste polyethylene plastic, it does so efficiently, at low cost and with a low energy requirement.

“We brought the temperature of the transformation down by hundreds of degrees,” Scott said. Conventional methods, according to the paper, require temperatures between 500 and 1000°C to break down the polyolefin chains into small pieces and reassemble them into a mixture product of gas, liquid and coke, while the optimal temperature for this catalytic process hovers in the neighborhood of 300°C. The relatively mild reaction condition helps break down polymers in a more selective way to a majority of larger molecules within a lubricant range, the researchers explained. “And, we simplified the number of steps in the process because we’re not doing multiple transformations,” Scott said.

No Solvents Required

In addition, the process requires no solvent or added hydrogen, just a platinum on alumina (Pt/Al2O3) catalyst for a tandem reaction that both breaks those tough carbon-carbon bonds, and rearranges the polymer’s molecular “skeleton” to form structures with those characteristic six-sided rings — high-value alkylaromatic molecules that find widespread use in solvents, paints, lubricants, detergents, pharmaceuticals and many other industrial and consumer products.

“Forming aromatic molecules from small hydrocarbons is difficult,” postdoctoral researcher Fan Zhang. “Here, during aromatics formation from polyolefins, hydrogen is formed as a byproduct and further used to cut the polymer chains to make the whole process favorable. As a result, we get long-chain alkylaromatics, and that’s the fascinating outcome.”

Source: UC Santa Barbara

ORNL Researchers Modify Microbes to Simplify Renewable Chemicals’ Production

 Oak Ridge National Laboratory scientists have modified a single microbe to simultaneously digest five of the most abundant components of lignocellulosic biomass, a big step forward in the development of a cost-effective biochemical conversion process to turn plants into renewable chemicals.

Engineering Bacteria to Produce Renewable Chemicals

The team engineered the Pseudomonas putida bacterium to consume glucose, xylose, arabinose, coumaric acid and acetic acid in a single bioreactor, eliminating the need for multiple tanks and microbes for each of those components. The one-pot process also breaks down lignin — traditionally a waste product of biomass conversion — so that every part of the plant can be used to create valuable products.

“We were pleasantly surprised at how quickly and well the microbe consumed these components, as they are structurally different and utilized via very different pathways. You had all of this carbon converging in the central metabolism and being co-utilized. It was pretty exciting,” said Adam Guss, who led ORNL’s research as detailed in Metabolic Engineering.

Upgrading lignin as well as sugars from biomass is vital to creating a highly efficient, cost-effective biorefinery. To reach that goal, lignin, which accounts for about 10%-30% of lignocellulose biomass by weight and represents up to 40% of total carbon, must be converted to value-added products to increase yield and reduce the cost of the overall bioconversion process.

ORNL scientists took P. putida, a hardy microorganism efficient at digesting glucose, coumarate and acetate, and optimized pathways for digesting those compounds, as well as xylose and arabinose. One of the major challenges in synthetic biology is to get an organism to co-utilize multiple compounds. The researchers used rational metabolic engineering, evolution and reverse engineering to cultivate these desired traits in the microbe.

The engineered microbe was then tested in a bioreactor on corn stover-derived biomass by project partners at the National Renewable Energy Laboratory as part of the Agile BioFoundry, a Department of Energy consortium that brings together the expertise and capabilities of nine national labs to advance state-of-the-art biomanufacturing.

Overcoming the Problem Using More than One Microorganism

The accomplishment also overcomes the problem of trying to use more than one microorganism in a single process bioreactor. “It’s hard to engineer two organisms that like the exact same conditions and play well with each other. Using a single, optimized organism eliminates a lot of those challenges,” Guss said.

Next steps in the work include further expansion of the number of substrates that P. putida can digest and gaining a better understanding of how these different pathways interact with each other to make the overall process as efficient as possible, Guss noted.

This study builds on a rich legacy of metabolic engineering at ORNL, part of its research that spans the spectrum from the development of hardy biomass crops, multifunctional microbes and other processes to valorize plant components to create clean, domestic, sustainably sourced fuels and chemicals that can support rural economies.

The project was supported by DOE’s Office of Energy Efficiency and Renewable Energy’s Bioenergy Technologies Office, and by ORNL’s Laboratory Directed Research and Development Program.

Source: ORNL

Canada Sets to Ban Six Single-use Plastic Items by End of 2021

Canada’s Minister of Environment and Climate Change, the Honourable Jonathan Wilkinson, announced the next steps in the Government’s plan to achieve zero plastic waste by 2030.

The Six Items Proposed for Ban

A key part of the plan is a ban on harmful single-use plastic items where there is evidence that they are found in the environment, are often not recycled, and have readily available alternatives. Based on those criteria, the six items the Government proposes to ban are:

• Plastic Checkout Bags
• Straws
• Stir Sticks
• Six-Pack Rings
• Cutlery
• Food Ware Made from Hard-to-Recycle Plastics

The Government of Canada is proposing to establish recycled content requirements in products and packaging. This will drive investment in recycling infrastructure and spur innovation in technology and product design to extend the life of plastic materials.

The Government wants to hear from Canadians and stakeholders on this approach to protect the environment from plastic pollution and reduce waste through a more circular economy. Comments will be accepted until December 9, 2020. Regulations will be finalized by the end of 2021.

Canada’s Strategy on Zero Plastic Waste

The Government of Canada is collaborating with provinces and territories through the Canadian Council of Ministers of the Environment. Together, all federal, provincial and territorial governments agreed to the Canada-wide Strategy on Zero Plastic Waste that lays out a vision for a circular economy for plastics, as well as a two-phase action plan that is being jointly implemented. Provinces, territories, and municipalities are leaders in the recovery and recycling of plastic waste.

The Government of Canada is continuing to work with them to strengthen existing programs and increase Canada’s capacity to reuse and recover more plastics. This will include collaborating with them to develop pan-Canadian targets to ensure that rules are consistent and transparent across the country, and make producers and sellers of plastic products responsible for collecting them.

Minister Wilkinson also took the opportunity to announce over $2M through the Zero Plastic Waste Initiative for 14 new Canadian-led plastic reduction initiatives. These projects are led by communities, organizations, and institutions, and will promote the development of new and innovative solutions to prevent, capture and remove plastic pollution from the environment.

Throughout the COVID-19 pandemic, the health and safety of Canadians is the Government of Canada's highest priority. Personal Protective Equipment (PPE) has played an important role in keeping Canadians safe, particularly the frontline health care workers. The ban on harmful single-use plastics will not impact access to PPE. The Government of Canada is also working with the provinces and territories, through the Canadian Council of Environment Ministers (CCME), and with the private sector to keep PPE out of the environment.

Source: Government of Canada

SI Group Launches Resorcinol-free and Bio-renewable Resin for Rubber Bonding

 SI Group has announced the launch of ELAZTOBOND™ B8-3410 modified phenol-formaldehyde thermoplastic resin for use in rubber bonding. ELAZTOBOND™ B8-3410 resin is based on bio-renewable materials and is resorcinol-free, making it a more sustainable and safer solution than traditional bonding resins used in the rubber industry. In addition to its improved safety profile, ELAZTOBOND™ B8-3410 has shown to offer comparable or better performance than resorcinol containing resins in aged and unaged testing.

Safer Material for Rubber Bonding Applications

ELAZTOBOND™ B8-3410 has been developed as a safer replacement for resorcinol and resorcinol-formaldehyde polymers in rubber bonding applications. “A bonding resin with zero free-resorcinol enables tire manufacturers to use safer materials in their factories while still achieving maximum performance,” stated Gordon McNeilage, business director at SI Group. ELAZTOBOND™ B8-3410 is particularly effective in applications where rubber compounds must bond to non-rubber components such as metal wire.

ELAZTOBOND™ B8-3410 is the latest addition to SI Group’s extensive high-performance rubber resin portfolio. Robert Kaiser, Vice President, Rubber & Adhesives shared, “SI Group is excited to introduce new, safer, and more sustainable solutions to the rubber and tire industry such as ELAZTOBOND™ B8-3410. We continue to leverage our long history of rubber resin excellence to innovate and solve our customers challenges.” ELAZTOBOND™ B8-3410 is commercially available and backed by SI Group’s global supply chain and customer care network.

Source: SI Group

Evonik Develops Osteoconductive PEEK Polymer for Improved Bone Fusion

 Evonik has developed a new osteoconductive polyether ether ketone (PEEK), VESTAKEEP® iC4800, for the medical technology market that improves the fusion between the bone and the implant.

With the introduction of the new biomaterial, Evonik is launching a new product line of next-generation, PEEK-based implant materials that it will market under the brand name VESTAKEEP® Fusion. Evonik will unveil the product at the virtual Eurospine conference October 6–9.

Easy Osteointegration for Accelerated Bone Fusion

The osteoconductive properties of the new PEEK material were achieved by using a special functional additive - biphasic calcium phosphate - and allow bone cells to adhere to implants more quickly, thus positively influencing fusion, so called osteointegration, at the boundary between the bone and the implant. This, in turn, will accelerate bone fusion and convalescence.

As the first biomaterial in Evonik’s new Fusion product line, VESTAKEEP® iC4800 will impress customers with its outstanding mechanical properties, which are similar to those of human bone. Similar to all other PEEK-based, high-performance polymers for medical technology applications, the newly developed biomaterial does not produce any artifacts in imaging processes such as X-ray or MRI. However, the additives provide a natural desired shadow for accurate placement and observation of the fusion process.

The new product line and its osteoconductive properties expand Evonik’s existing portfolio of biomaterials for implants in long-term contact with the body, offering a metal-free alternative to titanium implants.

Customer-specific Materials with Bioactive Properties

“Introduction of the new VESTAKEEP® Fusion product line represents an important step in the strategic development of our portfolio. This work draws upon our decades of expertise in polymer chemistry and on Evonik’s global innovation and production network. That foundation means we can offer patients a one-of-a-kind product and significantly improve their quality of life,” says Marc Knebel, head of the medical systems market segment at Evonik.

In addition to VESTAKEEP® iC4800, Evonik will offer to its customers within the new PEEK Fusion product line the development of further exclusive, customer-specific materials with bioactive properties as so-called VESTAKEEP® Fusion Select products. They are developed from a library of established osteoconductive substances with close involvement with each customer.

Excellent Processing Characteristics

Consciously developed for processing using a variety of production technologies, VESTAKEEP® Fusion will come both as a granulate and as a semi-finished stock-shape product. Like all previous PEEK products, it can be milled, compression molded, and extruded as usual.

Evonik’s new osteoconductive PEEK biomaterial can also be injection molded in the proven manner. It has been specially designed so that the functional additives are available on the surface and no film formation occurs. In collaboration with Samaplast, a Swiss company specializing in plastics engineering, Evonik has successfully demonstrated and documented the processing characteristics of VESTAKEEP® Fusion in injection molding.

Developing a 3D Printable Filament

Evonik’s polymer experts are also studying the possibility of developing a 3D printable filament with VESTAKEEP® Fusion for next-generation PEEK that could be processed using the fused filament fabrication (FFF) additive production technology.

Source: Evonik