A simplified process for the production/isolation of polymers from various feedstocks (e.g. fossil fuel or biomass). The English language is constantly evolving, which presents interpretation challenges due to issues related to a user’s choices or understanding of vocabulary, grammar and expression. One word that exemplifies this is ‘plastic’. Take a look in the dictionary and you will see ‘plastic’ can be either a noun or an adjective: • Plastic (countable noun), any one of a group of materials that when soft can be shaped into different forms, and has many different uses. • Plastic (singular noun), money (i.e. a credit card) to pay for something. • Plastic (adjective), soft enough to be changed into a new shape. When you have different possible definitions, complications are bound to arise, both for experts and the general public. These variations mean ‘plastic’ can be used to describe any material based on polymers (of which there are many examples). Just as importantly, a variety of materials display plasticity – including but not limited to clays and metals at high temperature – while not being what many of us would have previously thought of as plastic. The International Union of Pure and Applied Chemistry (IUPAC) is the world authority on chemical terminology. It develops and maintains recommendations that create a common language for the global chemistry community. Their definition of plastic is “a generic term used in the case of polymeric material that may contain other substances to improve performance and/or reduce costs”. For non-chemists among you, we hope that’s clear. If not, then it might comfort you to know that the IUPAC note that using the term ‘plastic’ instead of ‘polymer’ is a source of confusion even to their expert audience, and thus they do not recommend its usage. So then, let us instead consider ‘polymer’. IUPAC – them again – define a polymer as “A substance composed of macromolecules.” This is hardly the type of language we need to communicate with the general public when it comes to plastic usage and recycling, especially when they go on to define a macromolecule as “Amolecule of high relative molar mass, the structure of which essentially comprises the multiple repetitions of units derived, actually or conceptually, frommolecules of low relative molar mass.” If you were not confused before, the chances are, you are now. A simplified process for the production/isolation of polymers from various feedstocks (e.g. fossil fuel or biomass) is depicted in Figure 1, and rigorous life cycle assessments (LCAs) are necessary to understand the environmental impacts of each individual plastic product. There are multiple initiatives to facilitate us to reduce the amount of waste we create, encouraging and facilitating us to reuse, recycle or compost products. However, just as the term ‘plastic’ comes with many complications, so too the terminology related to recycling and recyclability, (bio)degradation and compostability can be complicated and difficult to 12 | Extraction of crude feedstocks of small molecules from oil/biomass 1 Purification of feedstocks of small molecule building blocks (e.g. monomers) Manufacturing items by polymer processing (e.g. melting, addition of fillers/plasticisers, etc.) Polymerisation of monomers (small molecules) to yield polymers (large/macromolecules) Different polymer architectures Macrocycle Cross-linked Comb Block Copolymer Linear Extraction of biopolymers from biomass (e.g. cellulose, lignins, polyhydroxyalkan oates, silk, starch).
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