Lightening the Plastic Burden | weatherology°
By: Meteorologist Michael Karow
Updated: Apr 28th 2020

Lightening the Plastic Burden

As covered in a previous article, plastic pollution is a growing problem in the global ocean. From the shores of remote, uninhabited islands to the seafloor of the deepest ocean trenches, plastic is becoming an ever-present part of aquatic ecosystems. About one-half of all the plastic pollution in the ocean can be attributed to gear used in commercial fishing, such as nets and rope. Now a team of chemists from Cornell University have created a plastic which is strong enough to use in commercial fishing, but which also degrades on a relatively short timescale upon exposure to the UV rays in sunlight.

The new plastic, called isotactic polypropylene oxide, or iPPO, was originally discovered in 1949, but has been little studied or improved upon until recently. The Cornell team found that iPPO has a strength similar to that of plastics like nylon 6,6 and high density polyethylene currently in use to make fishing nets and ropes. However, these plastics don’t easily degrade and thus tend to accumulate in the environment, over time. The lengths of the polymer chains in iPPO plastic, though, were shown in the lab to degrade by more than 75%, after exposure to UV light for 30 days. Thus, while iPPO is stable and strong enough for use during timescales of several days, if a piece of iPPO plastic is left behind, it won’t retain its strength and pose a hazard to wildlife indefinitely.

The Cornell team is working on further improvements to iPPO to hopefully achieve a plastic that disappears completely within acceptable timescales.

Sea turtle caught fishing net
Sea turtle caught in commercial fishing net - [Adobe Stock]
stress strain plastic iPPO Lipinski
Engineering stress vs. strain curves for various plastics used in fishing gear, including degradable iPPO - [Lipinski et al., 2020]
photodegradation iPPO Lipinski
Conceptual model of photodegradation of iPPO - [Lipinski et al., 2020]