Towards a new plastics economy

The first steps in the history of plastics were plant-based. A big innovation in 1862 was to treat the cellulose fibres of cotton with nitric acid, which yielded cellulose nitrate. This material was used in the manufacture of furniture, for example. The early 20th century saw the start of the manufacturing of plastic out of casein, which is one of the proteins in milk. Casein plastic was used in a variety of goods, including buttons, needles and knife blades.

Plastic can be made of raw materials other than oil

Oil-based plastics displaced their bio-based predecessors in the 1960s. Nowadays about 4-6 per cent of crude oil is used for the manufacture of plastic.

In recent years, natural raw materials, such as starch, cellulose, different sugars and vegetable oils, have been increasingly used. For instance, polylactide, which is used in rubbish bags for biowaste, is made out of lactic acid that can be manufactured, for example, from starch.

Digitisation needs plastic too

One reason why plastics are so popular is their diversity in terms of composition and properties. The properties of plastics can be tailored to suit their application, which makes them popular among material developers. In public discussion on plastics the focus is on the common plastics such as polyethene and polypropene, which are extensively used in packaging. Less attention is paid to special plastics that have been developed for use in extreme conditions, such as in the overalls worn by racing drivers, in the protective suits for firefighters, in space rockets and satellites.

Plastics are most frequently used in packaging. In Europe packaging accounts for about 40 per cent of the total use of plastics. Other major uses are in construction (20%), cars (9%) and electronics (6%). Nearly a third of the volume of electric and electronic waste is plastic. It is good to keep in mind that not even digitisation, including the development of artificial intelligence, is possible without the plastic components in electronics.

Plastics for treating hip and knee injuries

Plastics play a key role in health technology. Those of us who are middle-aged had the pleasure of getting amalgam tooth fillings containing mercury in our mouths as children, but thanks to plastics, these are no longer often used in the dental care of our children. Many of our grandparents are likely to have suffered from various hip and knee ailments, but our own parents have been lucky to get spare parts – made of plastics – to replace their worn-out joints, if needed.

What is the difference between plastics and polymers?

Plastics are made of long chain-like building blocks, called polymers, and various additives. Plastics are named according to the polymer they contain, although they also contain other substances. The properties of plastics are modified by mixing in various substances, including softeners, fireproofing and antimicrobial additives, and colour pigments. Fillers, such as calcite, talc and kaolin, reduce the shrinkage of plastics, thus improving the quality of plastic products. It is typical for plastics that at least at some stage of their production they can be shaped with the help of heat and pressure.

In addition to actual plastic material, polymers are also used in the manufacture of other goods including textile fibres, cosmetics, glues and paints. The so-called microplastic waste covers all “microparticle waste” that comes from polymers, which means that it comes from many different sources.

Biodegradability may depend on surrounding conditions

The term “bio-based plastic” is used if the carbon atoms of the polymer chains (mainly) originate from renewable sources. However, not all bio-based plastics are biodegradable. Biodegradability means that the material decays within a certain period of time through the action of ordinary microbes. A further challenge is that even though a material might be biodegradable in certain conditions, it might be non-biodegradable in some other conditions. For instance, the aforementioned polylactide is considered biodegradable, but some of the latest research results suggest that in the salty water of the oceans, polylactide breaks down very slowly.

The new plastics age

The circular economy brings new possibilities for plastics. Alongside the performance of a material, more attention needs to be paid to its recyclability and reuse. Material developers play a key role in the new plastics economy that is based on the circular economy. Different kinds of new technologies are needed for the “dismantling” of the structure of products and materials so that the raw materials they contain can be recycled in a sustainable and safe manner. Technological development is also central to the minimisation of emissions and to the cleansing of nature of the plastic waste that has already leaked.

Naturally, material developers cannot save the world on their own. Systematic action is required, to which the entire chain, consumers included, are committed. A good start is to reduce one’s personal consumption of disposable goods and to increase the sorting of personal waste flows. Society’s framework has been established by the EU plastics strategy and by the revision of the waste directives. This year will also see the publication of the Finnish national plastics road map, developed by the Ministry of Economic Affairs and Employment and the Ministry of the Environment.

In 1961 President Kennedy launched the Apollo space programme and declared in his famous speech a year later: “We choose to go to the moon … The challenge of space is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win.” In 1969 Neil Armstrong walked on the surface of the moon. I believe that with a strong vision, sufficient resourcing and co-operation, the challenges of the new plastics economy can be solved.