Lightweight and shatterproof, polyethylene terephthalate (PET) plastic is recyclable, although most items made from it don't get recycled. This is because reclaimed PET (rPET) just isn't as good as the original material. A new "upcycling" process, however, is claimed to make it even better.

Developed by scientists at the US Department of Energy's National Renewable Energy Laboratory (NREL), the technique involves first melting down discarded PET items such as bottles, then adding organic fibers obtained from plant waste. The ultimate end products are two types of fiber-reinforced rPET, which are said to be two to three times stronger and more durable than the original.

Additionally, it is estimated that the NREL technique will require 57 percent less energy than existing PET-reclamation processes, and that it will produce 40 percent fewer greenhouse gas emissions than standard petroleum-based composites manufacturing.

Although it's currently not possible to recycle the new types of rPET, the researchers are looking into methods of doing so. Existing first-generation PET can only be recycled once or twice, and as mentioned earlier, standard recycling techniques result in a material that is inferior in quality to the original.

"Standard PET recycling today is essentially 'downcycling,'" says Gregg Beckham, senior author of a paper on the study. "The process we came up with is a way to 'upcycle' PET into long-lifetime, high-value composite materials like those that would be used in car parts, wind turbine blades, surfboards, or snowboards."

The paper was recently published in the journal Joule.