Polymer Chemistry and the Problem with Plastics

As Director of the Grantham Centre for Sustainable Futures, I hear a great deal about how bad plastics are for the environment. But I’m also coming at the challenges of a sustainable food-water-energy nexus from my perspective as a University of Sheffield Professor of Polymer Chemistry – that is, a researcher in plastics!

Polymer production accounts for less than three per cent of crude-oil consumption and less than one per cent of the global energy budget. Overall, there is a beneficial (i.e. net negative) effect on global emissions due to polymers’ use in lightweight vehicles that have improved fuel consumption, thermal insulation that rescues the need for heating and air conditioning, and sensible food packaging that cuts down on waste, to give but three examples.

Polymers have an important role to play in energy capture (photo-voltaics and wind turbines) and storage (batteries and water splitting) too. We’re even using polyurethane foam as a synthetic soil in precision horticulture. So what we need to do is stop burning the fossil resource and maximise its beneficial use – in making plastics and other petrochemicals, and get our business leaders, policy makers and politicians to understand this.

The UN defines sustainability as “meeting the needs of the present without compromising the ability of future generations to meet their needs”. It’s a definition that has stood the test of time and comes from the 1987 Brundtland Report, Our Common Future, from the United Nations World Commission on Environment and Development. The United Nations Sustainable Development Goals provides another guide – in particular, goal nine, “Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation”, and goal 12, “Ensure sustainable consumption and production patterns”. My discipline offers it’s own definition: according to the International Union of Pure and Applied Chemistry, green chemistry is “the invention, design and application of chemical products and processes to reduce or eliminate the use and the production of harmful substances”. With words such as these, we can start to see through the greenwash.

These definitions can also help us perceive environmental impacts differently. The waste charity WRAP did a life cycle analysis to show that an ‘bag for life’ made from hessian has to be used 140 times to be less energy intensive per use than taking a new polythene carrier bag each time. And, if you reuse the polythene bag then the effect is compounded. Yet green consumers prefer hessian and paper to ‘nasty’ plastics, even when the evidence tells them otherwise.

Are there similar attitudes behind the current emphasis on ‘sustainable’ (that is, renewable) polymers? The feedstocks for sustainable polymers could come from renewable resources, but the production of those resources should use less water and energy than the petrochemicals they replace. Current commercial ‘sustainable polymers’ may be made from plant starch or oils, or from agricultural waste streams that do not compete with food production. But we don’t know whether using a renewable feedstock to make a plastic might, in fact, result in much greater greenhouse gas emissions because of all the processes involved.

A full life cycle analysis is needed to make the decisions about whether polymers are sustainable or not. Focusing on whether the feedstock is renewable isn’t enough. But who knows? Making polymers from CO2 and disposing of them into landfill, might turn out to be a great way to sequester carbon!


Picture courtesy of fdecomite

Trump’s America

I’m sat in the departure lounge at Dulles Airport in Washington after a thoroughly enjoyable but quite disturbing week in the USA. In Trumps 2nd week as President there is a constant stream of anti-Trump stories on CNN and the liberal (meaning centre-right) press are really on his case.

Despite the reports that he has the greatest disapproval rating of any incoming President, I’ve met plenty of people who think he is doing the right thing. The words I’ve heard most often are “he’s doing what he said he would do” and this is in the face of the evidence that, for example, that no refugee or immigrant from the 7 targeted countries has been responsible for any terrorist attacks or murders in the USA.

I met an Iraqi refugee, who is now a US citizen and a Houston taxi driver, who thought Trump was doing a great job and it was right to “pull up the drawbridge” even if I did put the words in his mouth. To be honest he seemed to like the phrase! My other Houston taxi driver was an Ethiopian refugee, and he too thought Trump was doing the right thing for US citizens, though by his own admission as a Christian persecuted in his own country he was pleased to see someone “sticking it to the Muslims”.

In contrast, the University of Sheffield Alumni I met in Houston were generally appalled by his election and what it might mean for the “liberal” city dwellers of the USA. They were even polite and engaging about my sustainability message, that fossil fuels were a historical anomaly, despite most of them working in the oil & gas industry.

Being polite, generally very hospitable and supremely nice is an overwhelming feature of my interactions with Americans, never more so than during the week I spent in Tennessee.

I was in Oak Ridge, at the National Laboratory , the place where the Manhattan Project made the plutonium in the Graphite Reactor– that is now a museum.

I was visiting the SNS (Spallation Neutron Source) where my old friend Wim Bras has just taken a job. I was joined by Chris Ober from Cornell and we were planning experiments that we will do to reduce the fuel consumption of ships. We hope to do this by using some clever polymers physics, preventing the growth of sea weed and barnacles by stopping their adhesion to the bio-film that is formed on the ships hull. This is currently done by poisoning. We will use neutron scattering to look at the surface structure of the films we make, and do it under a layer of bio-film(bacteria) that we have made transparent so we can see the (re)arrangement of the paint molecules underneath.

Running a laboratory that can do such things requires a lot of money and really talented people, so Oak Ridge has both. In the SNS the majority of the scientists are immigrants, in fact only one of the senior management team was born in the USA. Across the Oak Ridge National Lab there are people from every nation on the earth, Chinese and Russian, Iraqi, Iranian and Libyan. Some of them intellectual and economic migrants, some of them refugees, lots of them with security clearance. The economic engine of the USA relies on recruiting talent and labour from around the world. Which makes current events more astounding.

My friends Wim & Jose are understandably concerned about what their future holds as recent immigrants who have just bought a house in Knoxville Tennessee. But the people they will live amongst are genuinely lovely. In a restaurant parking lot a fella beckoned us over as we drove in to tell us “I’m just leaving, y’all, and I have a beautiful parking spot just waiting”. As Wim said “that could never happen in France”, the country he had just left.

When they wish you well here they mean it – really mean it – despite race, creed or colour. The problem is that this hospitality only really applies to individuals and not identified groups. Knoxville is the buckle in the bible-belt, so God help you if you are a gay couple, or on a team-building exercise from a family planning clinic!

So Wim and Jose will have a fine time, their neighbours will bring them food over when they move in and make them really welcome. But every time they turn on the radio and TV they will be assaulted by attitudes and values that are abhorrent to them (and me too) but those views will rarely trouble their personal interactions. And that is the most confusing aspect of being here.

Picture courtesy of Giuseppe Milo