More sustainable cosmetics for a clean environment

Part two of our series of articles about sustainability takes a look at the use of microparticles in cosmetics and personal products. The particles used frequently involve plastics, which, however, represent a problem for the environment – as we are in the meantime aware. Scientists have started to search for an adequate replacement and have evidently succeeded in finding one.

There is plenty of evidence to prove it: the microplastic particles used in cosmetics and personal products are a problem [1-6]. Microplastics enter the environment primarily via waste water, reaching inland waterways and, finally, the world’s oceans, without even rudimentary attempts being made to filter them out or eliminate them completely in sewage plants.

Microplastics a problem
Organisms that live in water confuse microplastics with food or ingest them when they eat. It is problematic that microplastics contain additives that are harmful to health and can incorporate pesticide residue or other pollutants from the environment. Inflamed tissue has been found in shellfish that have ingested microplastics. The health of human beings is threatened by microplastics too, when they are eaten with food, e.g. in the form of contaminated seafood.

Searching for an alternative
Research scientists at the Fraunhofer Institute for Mechanics of Materials (IWM) in Halle, Germany, have set themselves the goal of making major contributions to the development of measures that stop this. In the context of their work, they are looking for solutions to replace polymer-based microparticles of the kind used in cosmetics and personal products.

Microplastic particles are used in toothpaste or exfoliation products as stabilisers or abrasives: their purpose is to remove unsightly plaque in toothpaste and dead skin in exfoliation treatment. Depending on the application, microplastics account for up to 90 per cent of the product.

Discussion and enforcement of a ban on microplastics
Due to their harmful effects on the environment, some US states have already prohibited the use of microplastics in cosmetics and personal products, while consideration is being given to a ban in the European Union (EU). This is the context in which IWM is carrying out its mission, which has focussed on research into potentially viable substitutes that have comparable product properties but have no adverse effects on the environment and are, ideally, degraded under natural conditions without leaving any traces or residue.

Cellulose is a possible substitute
This is where the “KosLigCel” project begins, which is being co-ordinated by the Fraunhofer Institute for Mechanics of Materials (IWM) in Halle. “Polyethylene is generally used for microplastic particles in cosmetic products at the present time. We, on the other hand, want to use particles from a natural product, i.e. cellulose that is made from beech wood scraps and is biologically degradable”, explains Project Manager Dr Vanessa Sternitzke from Fraunhofer IVM.

If the project proves to be successful, it would be a valuable contribution to reduction of environmental pollution by microplastics. Project Manager Vanessa Sternitzke draws attention in this context to a study carried out by the United Nations (UN), according to which 4,300 tonnes of microplastic particles were used in personal products in 2012 in the EU alone, all of which are in the final analysis inevitably released and enter the environment in the course of their use. These 4,300 tonnes of plastic can be used in future for processes and products that make greater long-term sense.

There needs to be a starting point for everything
The current “KosLigCel” project, that is scheduled to take two years and is part of the cutting-edge “BioEconomy” cluster initiated by the German Ministry of Education and Research, includes the planned development of an exfoliation product and a toothpaste. CFF GmbH, a pulp processor from Gehren (Thuringia, Germany), which is providing cellulose and lignin particles for the project, and Skinomics GmbH from Halle, which is responsible mainly for dermatological testing of the new products, are partners in the project.

The IWM reports that the particular challenge is to find or develop a substitute material that has the required property profile, i.e. corresponds in size, shape, hardness and surface structure to the microplastic particles that are to be substituted and at the same time has no adverse effect on skin. What is comparatively easy with synthetic polymer materials that can be customised to meet individual specifications and objectives proves to be a challenge when natural ingredients are being used.

Focus on new approaches
In their attempts to reach the goal they have set themselves, the IWM research scientists are working on modification of the beech wood cellulose and analysis of it down to the microstructure level. The use of cellulose from other sources, such as material left over from oat, wheat and corn production, is being investigated too. For the first time, the research scientists also want to test the use of modified sulphur-free organosolv lignin particles in cosmetic products.

Isolated attempts have been made to replace microplastic particles in cosmetic products by such other materials as wax, salt or olive seeds. Substitutes of this kind have never been evaluated at the material science level up to now, however. The aim is to change this in the course of the KosLigCel project: “Tremendous scientific challenges still need to be overcome in order to find a substitute for polyethylene that works just as well but is biologically degradable in water – in contrast to polyethylene – and can be manufactured as inexpensively as possible”, says Dr Vanessa Sternitzke. The plan is to find out as precisely as possible what the decisive criteria for the required properties are. The Project Manager is convinced: “When we know this, we can evaluate reliably which materials are particularly suitable for replacing microplastic particles.”

Better use of polymers, creation of added value
Ideally, the use of cellulose could in addition open up further application areas. Because cellulose absorbs water and oil too, in contrast to polyethylene. This capability could, incidentally, help to improve the long-term effect of moisturising creams. The cellulose particles are a potential filling agent in aluminium-free deodorants too. The 4,300 tonnes of polymer material that have been channelled into the production of microplastics for cosmetics and personal products up to now will be used for more sustainable applications in the foreseeable future.