One need only look out their window to see first-hand evidence of the plastics pollution we currently face. It was reported in 2017 (Geyer, Sci. Adv.) that since 1950 around 6300 million metric tonnes of plastic waste have been created. Of this enormous amount of waste, a mere 9% has been recycled and 12% incinerated, with the remaining 79% ending up in landfills or oceans. Despite numerous advantages, many related to energy and resource efficiency, the detrimental effects of “single use” plastics are indisputable, and clearly things need to change with regards to consumer demand and use of these disposable materials.

Chemically speaking and as defined by IUPAC, a plastic is a “polymeric material that may contain other substances to improve performance or reduce costs”. We therefore question the broad classification of single use plastics being ‘bad’ and instead suggest that the issue we face is the bad use of plastics. Even those plastics deemed ‘bad’, like polypropylene and polyethylene, are ideal for the purposes, like disposable bottles, supermarket bags, and plastic packaging, with which they are now associated – it is their impact post use that causes controversy. These plastics, and many others, also have uses inherent to our daily lives with lifetimes of twenty or more years that we cannot discount. Polypropylene is used in thermal undergarments, as well as in reusable plastic containers. Polyethylene makes up many industrial machine components and artificial joints. These subsets of applications offer significant positive impact that more than offsets their current ‘bad’ reputation.

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Overcoming the ‘bad use’ of plastics

The necessary shift in our approach to overcoming our bad use of plastics is the responsibility of all those in the plastics chain – the industry, the users, and the government. Luckily this change in mindset is already underway. Users are becoming more conscientious in their use of multiple-use alternatives to common plastic products and the ways in which they recycle waste. Increasing numbers of multinational companies, including Ikea, Coca Cola and McDonalds, have committed to ensuring that their plastics are both recyclable or compostable, and incorporate increasing proportions of recycled plastic. Several government bodies are introducing levies or bans on some of the most problematic plastic items, like bags, straws and microbeads, as well as funding of research towards recyclable alternatives. There is also significant work in many areas of the plastics industry itself to make plastics in more environmentally conscientious ways – whether in the precursors used, many of which are typically petrochemical in origin, in the efficiency of manufacture, or in their ability to be more easily recycled.

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Polyurethane – A case study

Polyurethane (PU) is present in our daily lives in more ways than one might expect. This plastic, the third most widely used behind polyolefins and PVC, accounts for approximately 10% of all plastics produced, and is forecast to generate close to $80 billion worldwide by 2021, or 20 million tonnes annually (Ceskaa, 2017). Rigid foams make up the insulation in our walls, which facilitate a decrease in heat loss of ~60% when compared to other insulative materials (Kingspan, 2018). Flexible foams add comfort to our lives in the form of memory foam mattresses. Coatings protect our clothing, wooden floors and vehicles to extend their useful life. Adhesives stop our shoes from falling apart. Elastomers make up the wheels that allow us to open drawers and ride rollercoasters. Simply put, the stability and durability of PU in any one of its forms is essential in protecting us and our essential items from wear and tear and the elements.

 

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Alternatives to PU

The production of PU is an energy and petrochemically intensive process – replacing this material with alternative biodegradable/natural/energetically less demanding materials is a natural initial response. Certainly, one could envisage replacing PU insulation (160 kg CO₂ emitted / kgCO₂e), with a less carbon intensive material like cork (-155 kgCO₂e), glass fibre (8 kgCO₂e), or mineral wool (38 kgCO₂e) (superhomes.org.uk). In these examples, however, more than twice the material is required to prevent the same amount of heat loss as PU, so the performance of these long lifetime materials with regards to their stability, flexibility, lifetime, handling and fitness for purpose must also be evaluated. When considering natural alternatives to PU, we also mustn’t forget to factor in the environmental and societal effects of these materials, like import costs, land and water intensive agricultural demand that competes with food crops, the need for fertilisers and pesticides, or the waste profile associated with such materials. When considering each of these points, the greening of PU production becomes a superior approach to offsetting its overall carbon and environmental footprint.

The historical production of PU and its precursors was heavily dependent on volatile organic compounds and petrochemical-based feedstocks, both of which are being addressed by new and existing companies worldwide. One of the biggest contributors to the use of petrochemical-based feedstocks in PU manufacture is the polyols inherent to its chemical structure. These polymers are most commonly polyether in nature and are prepared from the catalysed polymerisation of ethylene or propylene oxide. These epoxides are industrially synthesised from the carbon intensive oxidation or hydrochlorination of the corresponding alkene, which is collected as a by-product of oil refinement and which has an enormous carbon footprint. The potential replacement of some or all of this epoxide feedstock is clearly an effective approach to greening polyol production.

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Plant-based polyols

Increasing numbers of natural polyols based on plant oils or compounds are being developed industrially. Oil-based polyols can be prepared from a range of natural oils, such as castor, cashew, peanut or soy, with castor oil being one of the few natural products that does not require chemical modification. Alternatively, bio-based succinic acid polyols can be prepared from the fermentation of sugar. These polyols, in particular bio-based polyols, do offer advantages to downstream PU products over their wholly petrochemical-based counterparts in terms of increased abrasion resistance, tensile strength, thermal properties and hardness. As in the case of natural alternatives to PU however, these polyols also run into agricultural shortcomings, especially in competing with food crops for land use, as well as dependence on variable and uncontrollable factors like weather and seasons. As such, when processing and purifying the polyols, it can be difficult to produce constant quantities for downstream use. Furthermore, natural oil-based polyols require additional processing to remove odour, and typically must be blended with traditional petrochemical-based polyols to achieve comparable properties.

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Using CO₂ as a feedstock

An abundance of atmospheric CO₂ presents another environmental issue that we currently face. It would therefore offer a win-win situation if petrochemical-based polyol feedstocks could utilise an otherwise waste material – for every tonne of epoxide replaced by CO₂, three tonnes of CO₂ would be avoided or utilised (Bardow, Green Chem.). Assuming 50% market adoption of such technologies, these numbers correspond to savings of ten million tonnes of CO₂ a year, the equivalent to taking six million cars off the road or planting twelve million trees, that is, significant savings. Such polyols, known as polyethercarbonates, are the focus of a small, but increasing, number of companies. These new technologies differ in the amounts of CO₂ that can be incorporated into polyols, but with a theoretical maximum of 50 mol%, significant environmental advantages are clearly possible. We at Econic 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 needs. What’s more is that the incorporation of CO₂ also offers significant product advantages – the resultant rigid foams have improved flame retardance, whilst coatings, adhesives, sealants and elastomers show increases in their chemical, temperature and hydrolytic resistances. Economically, waste CO₂ is expected to be at least an order of magnitude cheaper than its petrochemical-based counterparts. Irrefutable advantages are achievable in all aspects of the production of these green polyols, benefits which are in turn passed through to the PU industry and their consumers.

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Moving towards responsible plastics

Frankly speaking, we cannot, and should not, remove plastics from our lives. The positive energy and application impacts that they impart simply cannot be reproduced by natural alternatives. Manufacturers and users alike can have a huge influence on reducing the ‘bad’ impact of plastics and shifting the balance towards ‘good’. We must urgently address how efficiently we use each plastic and move away from a ‘use and dispose’ mentality. Furthermore, plastics should be manufactured so as to not further perturb the state of our environment, but also to utilise the abundance of harmful waste products we have already created. As in the case of increasingly green PU, green and recyclable alternatives to many of the other plastics we rely on are being developed worldwide. The issue we now face is the wait for these new technologies to be adopted on a large scale by the industry, so that the plastics products so essential to our lives move towards being responsible materials.

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To learn more about the endless potential that Econic’s catalyst technology can bring to greener plastics and waste CO₂, please contact:
Richard French, Business Development Director on +44 1625 238 645

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This blog was first posted by Plastic News Europe on 17/09/2018.

Author, Anthea Blackburn

As the Northern Hemisphere’s temperatures continue to soar, along with the spirits of those who follow World Cup football, the shortage of CO₂ in the UK is becoming more and more apparent. Besides the obvious (and vitally important) use of CO₂ in adding the fizz to beer and soft drinks, it is also invaluable in a variety of other food-related fields, including, but not limited to, increasing the shelf life of pre-packaged meat and produce and cooling foodstuff in transit, as well as in a variety of medical devices and in crude oil extraction.

One might ask how we could be experiencing a CO₂ shortage considering the issues with the abundance of atmospheric CO₂ we are currently working to overcome. Unfortunately, both the inherent chemical stability and relatively low atmospheric concentration (~0.04% by volume of the atmosphere) of CO₂ make its isolation for use in other applications somewhat of a currently cost-prohibitive issue. While the primary production of atmospheric CO₂ stems from the ever-increasing burning of fossil fuels and deforestation, there are also significant amounts generated through a variety of industries, such as those involved in chemical manufacturing, cement production, or petroleum refining. Fortunately from a process perspective, it is possible for a large number of these industries to collect and store the CO₂ that they create as part of their everyday business. They only require then the means with which to safely dispose of or utilise this waste product. And so enters the field of Carbon Capture, Storage and Utilisation (CCSU).

The CCSU industry is made up of three sections – firstly, the sequestering and purification from other gases of CO₂ from the atmosphere or as industrial waste; secondly, its storage; or thirdly, its use as a chemical feedstock in the production of value-added products. Carbon capture is undoubtedly a necessary component of CCSU as we continue to produce more and more CO₂, and a number of companies exist that aim to take the captured gas and store it indefinitely and out of harm’s way. One such example can be seen in Norway, who have been capturing and storing CO₂ from industrial processes for close to 20 years. More recently, with the backing of the Norwegian government and assistance from oil companies Equinor, Shell, and Total, the country are moving towards the introduction of a technology that will transport the captured CO₂ to the North Sea, where it will be buried underground. Once in place, this approach will also be available to other countries in the area, and offers a viable alternative to simply releasing the gas into the atmosphere.

A similar approach to CCS has also been developed in Iceland by an international team known as CarbFix, who capture CO₂ from industrial processes and store it in the basaltic mountains where it turns into rock within only a few months. This success is, in part, possible due to the filter technology developed by Swiss company ClimeWorks, which selectively chemically removes CO₂ from the steam generated by a geothermal plant, and concentrates it in water as carbonate ions, which is injected into the ground. This approach is also a possibility in other basaltic regions like Siberia, Western India, Saudi Arabia and the Pacific Northwest, though further advances are required to reduce the water intensive requirements of the technology.

ClimeWorks have also taken their CCS technologies a step further in enabling the purified CO₂ to be used, rather than stored indefinitely. This captured CO₂ can also be isolated for use as a renewable onsite source of CO₂ by the food and agricultural industries, as well as those that use CO₂ as a fuel or chemical feedstock. A similar type of extraction technology has also been developed by Carbon Engineering, a Canadian company, who, in conjunction with their hydrogen generation technologies, use the CO₂ to create clean diesel and jet fuels.

In order for CO₂ to be utilised via its conversion to another more valuable form of carbon, its inherent chemical stability must be overcome: CCU technologies are required. Many such technologies are available (the following is by no means an exhaustive list!), which are useful in so many different industries. One such industry is that of concrete, which is used in its various forms more than any other artificial material in the world. Unfortunately, in its standard form, the manufacture of concrete is extremely energy and resource intensive and generates higher CO₂ emissions than almost any other industry. A number of companies exist to rectify these downsides of such an invaluable material, two of which are focused on CCU approaches. CarbonCure technologies allow the CO₂ emitted during cement preparation to be transformed into nanosized mineral carbonates that are embedded within the concrete formed. This process can be retrofitted to existing manufacturing assets and also enhances the properties of the resulting material. A somewhat similar approach has been developed by UK-based Carbon8 Aggregate, which uses CO₂ to not only transform thermal waste into artificial limestone, but also to solidify the resulting aggregate. This process is remarkable, in that the resulting aggregate has captured more CO₂ than is used in the energy required in its manufacture, resulting in the world’s first carbon negative aggregate. Alternatively, Carbon Upcycling uses waste CO₂ to solidify a pre-formed and almost carbon neutral building block that resembles concrete and can be used in construction applications where concrete would typically be utilised. What’s more is that the additive nature of this material’s preparation offers the potential for its generation using, for example, 3D printing, which would accelerate construction timelines and decrease the labour intensity required in its manufacture.

The use of CO₂ as a chemical feedstock is another vital aspect of CCU developments – like that of Econic’s innovative catalyst technologies that transform waste CO₂ into polyols for use in the plastics industry. Exploiting a similar chemical transformation, Newlight uses a naturally-occurring microorganism-based biocatalyst to transform concentrated CO₂ or methane gas into a high performance PHA-based biopolymer that can be used as an alternative to fossil fuel-derived polypropylene, polystyrene, and TPU in a range of applications. CO₂ can also be introduced into the electronics and automotive industries as a carbon composite through the preparation of carbon nanotubes using methodologies developed by C2CNT. The carbon nanotubes are prepared using electrolysis, which is a much more cost-effective alternative to the methods of chemical vapor deposition or polymer pulling used currently.

It is clearly evident from this small subset of examples that a huge amount of work is going into the development of technologies that can not only remove harmful CO₂, and its effects, from the atmosphere, but also to transform this gas into a chemical that adds economic, product and environmental value to the often fossil fuel-based feedstocks or cost-prohibitive processes that we currently employ. While these solutions unfortunately do not overcome the UK’s impending beer shortage and decreased shelf life of fresh produce, it is surely reassuring to know that the abundance of CO₂ in our atmosphere is being removed for our gain in other ways.

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To learn more about the endless potential that Econic’s innovative catalyst technology can bring to waste CO₂, check out how Econic can make this possible, or contact:

Richard French, Business Development Director Econic Technologies | +44 1625 238 645

Author, Anthea Blackburn