University researchers develop plastics from biomass

A team of chemical engineers from the University of Massachusetts Amherst and the University of Delaware claims it has discovered a new way to make plastic bottles from biomass rather than petroleum.

Researchers that made the discovery are part of the Catalysis Center for Energy Innovation (CCEI), which is comprised of more than 20 faculty members working together to create new technologies for the production of biofuels and chemicals from plant biomass.  The center is funded by the U.S. Department of Energy.

Paul Dauenhauer, chemical professor at UMass Amherst, told PlasticsToday one of the major goals of the center is to effectively utilize sugars for the production of renewable polymers including PET.

The new discovery demonstrates an efficient, renewable way to produce the chemical p-xylene, or paraxylene, according to the news release.

"You can mix our renewable chemical with the petroleum-based material and the consumer would not be able to tell the difference," Dauenhauer said.

The first step in the process is the conversion of lignocellulosic biomass such as trees or grasses to sugars such as glucose, Dauenhauer said. The team then removes some of the oxygen from the sugar to produce a new molecule called dimethylfuran. The final step includes the addition of dehydrated ethanol, which results in the chemical, p-xylene. 

At this point, p-xylene can be directly blended into existing PET processes for production of plastic products, he said.  

The researchers called this a major breakthrough since other methods of producing renewable p-xylene are either expensive or inefficient due to low yields. 

"Our discovery shows remarkable potential for green plastics, particularly those used to distribute soft drinks and water," said Dion Vlachos, director of the University of Delaware's CCEI. "This technology could significantly reduce production costs for manufacturers of plastics from renewable sources."

A key to the success of the new process is using a catalyst specifically designed to promote the p-xylene reaction over other less desirable reactions. The catalyst and chemical reactor were developed specifically to combine two molecules together. 

"We discovered that the performance of the biomass reaction was strongly affected by the nanostructure of the catalyst, which we were able to optimize and achieve a 75% yield," said Wei Fan, assistant professor of chemical engineering at UMass Amherst.

The research team believes further modifying the process could potentially boost the yield and make it even more economically attractive.

There are other processes designed to produce biobased PET bottles.

For example, biotechnology developer Avantium touts its PEF material will become the next-generation biobased polyester, as it's designed to become a drop-in replacement for PET. PEF is made with Avantium's YXY technology, a chemical-catalytic method to convert non-food based carbohydrates produced from plants, grains, energy crops, lignocellulosic matter, waste streams, waste paper or agricultural residues, into a wide variety of biobased polymers.

Dauenhauer said what makes the CCEI process unique is the group actually produces p-xylene rather than a functional alternative. 

"For this reason, our process will lead to a plastic product with identical properties to existing PET plastics," he said. "Our process is entirely thermochemical and does not require fermentation. Finally, our process only produces p-xylene and not other xylene isomers. Competing technologies produce a mixture called BTX, of which a fraction of the BTX is p-xylene."

One opportunity to quickly implement this discovery would be to license the technology to a biomass company, which could implement the group's technology within an existing biomass production facility, Dauenhauer said.