Could a greenhouse gas make plastics ‘green?’

Carbon dioxideSeattle has become one of the latest cities to ban plastic straws. It is not alone in this movement: From the New York State Senate considering a ban on plastic bags to a major UK newspaper calling for a total ban on the material, plastic is seen as an environmental enemy.

These concerns are not baseless: Almost 80% of the 6,300 million metric tonnes of plastic created since 1950 has ended up in landfills or the oceans. Anyone who has seen the images of marine life sharing their habitats with discarded plastic bottles and bags can’t help but want to act.

But we need to ensure this eagerness is directed correctly. Plastic is more than the single-use, throwaway applications with which it is most commonly associated. In fact, it is a manufacturing staple integral to the modern world. An outright ban is simply unfeasible.

Plastic has many jobs and performs them effectively. Whether it is as durable coatings and insulators; the polycarbonate that goes in our phones; the polyurethane used throughout our cars; or the polyethylene in milk bottles, we are, perhaps unknowingly, inherently reliant on plastics. Our world would be significantly less efficient without them.

Rather than consider an outright ban, we need to think about how we can make existing products “greener.” Steps are already being taken: McDonald’s and Coca-Cola, for instance, have committed to ensuring that their plastics are recyclable or compostable, while also increasing the proportions of recycled plastic they use. 

One solution is to replace plastic with biodegradable alternatives. Although this approach may make a product greener, it may also decrease the product’s efficiency: Natural materials like cork, glass fiber or wood require more than twice the material to prevent the same amount of heat loss as polyurethane (PU). Of course, this isn’t even accounting for the demands the production of these natural alternatives place on agricultural resources.

A sustainable solution lies in an unexpected place—the atmosphere or, more specifically, in carbon dioxide (CO2), the other villain of the modern world. This greenhouse gas presents us with significant environmental, economic and productive potential, which, thanks to recent developments in catalytic science, can be incorporated into PU on an industrial scale.

Wide adoption of CO2 as a raw material would be a win-win. In polyols used to make PU, for example, for every tonne of petroleum-based epoxide replaced by CO2, three tonnes of CO2 would be avoided or utilized (Bardow, Green Chem.). Such polyols, known as polyethercarbonates, are the focus of an increasing number of companies aiming to realize these significant environmental advantages. At Econic, where I work, we have taken this approach one step further: Our catalyst technologies allow for the bespoke incorporation of CO2 into polyols at industrially relevant temperatures and pressures, thereby allowing polyol producers to tailor their products for their downstream PU users’ needs.

What’s more, the incorporation of CO2 also offers significant product advantages: The resultant rigid foams have improved flame retardance, while coatings, adhesives, sealants and elastomers show increases in their chemical, temperature and hydrolytic resistance. Economically, waste CO2 is cheaper than its petrochemical-based alternatives. Irrefutable advantages are achievable in all aspects of the production of these green polyols, benefits that are, in turn, passed along to the PU industry and its consumers.

The problem lies not in plastic itself, but in our use of the material. The solution lies in making the product greener, not in pursuit of a total ban. And perhaps fittingly for a material so widely decried, the savior is quite possibly the only compound that is more maligned—carbon dioxide. Plastic and carbon dioxide have positive potential, we mustn’t forget this.

About the author

Anthea Blackburn, EconicAnthea Blackburn, PhD, is a Scientist, Catalyst Development, at Econic Technologies, based in the Alderley Park science hub near Manchester, UK. The company is dedicated to applying catalyst chemistry to turn waste CO2 into positive economic and environmental potential. Its catalyst technology, initially developed by Professor Charlotte Williams, then at Imperial College London, and now Professor of Inorganic Chemistry in the Department of Chemistry at the University of Oxford, has been patented and validated in pilot operations.

Comments (0)

Please log in or to post comments.
  • Oldest First
  • Newest First
Loading Comments...