Selective Recovery of Ethylene Vinyl Alcohol from K-Cups

The inability to reclaim valuable barrier polymers from multilayer plastics used in food packaging contributes to the growing problem of plastic waste accumulation. Recycling multilayer plastics using thermomechanical methods results in the higher value barrier polymer being diluted in commodity polymer recycling streams and can affect the processing and properties of recycled materials. We report that dimethyl sulfoxide (DMSO) can be used to remove the barrier polymer ethylene vinyl alcohol (EVOH) from polyolefin containers. Single-use coffee containers, commonly known as K-Cups, were collected and placed in hot dimethyl sulfoxide. The polyolefin layers remained undissolved, while the EVOH dissolved in the DMSO. The extracted EVOH had similar thermal and spectroscopic properties to virgin EVOH polymers but different rheological properties. This work highlights that relatively simple chemical extraction strategies can be used to enable separation of higher value barrier polymers from commodity polymers like polyolefins.