Technological watch

Reclaiming the value of plastic waste has been on the front burner for many companies recently, and several are on the path to commercializing their innovations, including and the folks at IBM’s laboratory with their process. This week, researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL; Golden, CO) announced their take on plastics upcycling—transforming discarded products into new, high-value materials of better quality and environmental value, with the goal of incentivizing recycling of waste plastics.

NREL Senior Research Fellow Gregg Beckham and Materials Scientist Nic Rorrer. Image courtesy Dennis Schroeder/NREL.An article in Joule describes how the NREL team chemically combines reclaimed polyethylene terephthalate (PET) plastic, in the form of single-use beverage bottles, with bio-based compounds to produce higher-value, fiber-reinforced plastics (FRPs) that can be used in products ranging from snowboards and vehicle parts to wind turbines. Not only are the resulting composites worth more than double the original PET, the FRPs exhibit twice the strength and improved adhesion to fiberglass when compared with standard petroleum-derived FRP, claims NREL.

In an online press conference on Feb. 28, NREL Senior Research Fellow Gregg Beckham said that recycling can save between 40% and 90% of embedded energy in plastics and save money, as well. However, he noted that “most recycling today is downcycling—there’s very little financial motivation.” Beckham, one of the primary authors of the paper, added: “Knowing that 26 million tons of PET are produced each year but only 30% of PET bottles are recycled in the United States, our findings represent a significant advancement in enabling the circular materials economy.”

We can’t demonize plastics because they have contributed many benefits to society, but the fact is that “many countries don’t have the infrastructure to deal with plastic waste,” he said.

NREL started its project with PET because it is considered the easiest plastic to recycle. However, rather than going the mechanical recycling route, in which material properties are often compromised and, thus, go into lower-value products, the idea of the NREL team is to combine PET with diol (ethylene glycol) from non-food-plant biomass to produce fiber-reinforced composite materials to make products that are much more valuable, such as wind turbine blades, surfboards, snowboards and even automotive parts.

NREL performed a supply-chain analysis of the FRP materials that found substantial energy savings (up to 57%) and a 40% reduction in greenhouse gas emissions when compared to the process for producing petroleum-based composites.   

Beckham noted that a life cycle analysis showed traditional energy consumption (collection, melting and so forth) for producing fiber-glass-reinforced plastics is 88 megajoules (MJ) per kilogram of material at a cost of $22/MJ. Using NREL’s process, that can be reduced to 42 MJ/kg at a cost of $10/MJ.

The NREL team also included staff polymer researcher Nic Rorrer, who has previously worked on bio-based muconic acid and breaking down reclaimed PET. “We are excited to have developed a technology that incentivizes the economics of plastics reclamation,” Rorrer said in a prepared statement. “The ultimate goal is to reduce the amount of waste plastics in landfills and oceans.”