US researchers develop new multiblock polymer for plastic recycling

28 February 2017

The Tisch University Chemistry and Chemical Biology professor Geoffrey Coates and his team has worked with a group of researchers from the University of Minnesota to develop multiblock polymer, which could boost plastic recycling.

Polyethylene (PE) and polypropylene (PP) cannot be repurposed together as they feature different chemical structures. These two constitute about two-thirds of the world’s plastics.

The researchers have added a new multiblock polymer to a mix of the two incompatible materials for creating new and mechanically tough polymer.

Coates team is comprised of postdoctoral researcher James Eagan, researcher Anne LaPointe and former visiting scientist Rocco DiGirolamo.

The Center for Sustainable Polymers, a National Science Foundation (NSF) Center for Chemical Innovation has provided the financial support for the collaboration between Coates’ group and the group led by University of Minnesota chemical engineering and materials science professor Frank Bates.

The new polymer has been created by adding a miniscule amount of newly developed tetrablock (four-block) polymer to the alternating polyethylene and polypropylene segments. It has enhanced strength than diblock (two-block) polymers they tested.

Two strips of plastic have been welded together by using different multi-block polymers as adhesives. Later, they were mechanically pulled apart.

Welds made with diblock polymers failed relatively quickly, compared to the welds made of the group’s tetrablock additive, which held better that the plastic strips broke instead.

Coates said:  “People have done things like this before. But they’ll typically put 10 percent of a soft material, so you don’t get the nice plastic properties, you get something that’s not quite as good as the original material.”

Coates is co-founder of Novomer, which deploys Cornell-developed catalyst technologies to produce cost-effective and environmentally responsible polymers and chemicals.