Not all nanoparticles have to be meticulously crafted from the top downwards research finds
Most people wouldn’t naturally associate mining with nano- or green technology, would they? But at Imerys, the world’s leading producer of industrial minerals, that’s exactly what they do, and they’ve dedicated a significant proportion of their R&D effort to both of them.
Nanotechnology is a term that embraces such an enormous range of subjects that it can be hard to understand what it actually means. In material science, however, it’s more specific; it’s about the use of nanometre-sized particles of often quite ordinary substances to obtain new and useful properties that don’t exist at other scales. The earliest examples are becoming well known – suncreams, self-cleaning glass, scratch-resistant coatings and carbon nanotube reinforced composites are typical. All of these use synthetic nanoparticles made by cooking up various chemicals, often in the gas phase, at very low throughput and using large quantities of energy. So, not surprisingly, they come with a hefty price tag.
Natural industrial minerals, by contrast, are found everywhere – in ceramics, beer and wine production, cosmetics, paints, paper, plastics and rubbers – where they reinforce, filter, toughen, stiffen and above all whiten the materials of our daily lives. The need for whiteness specifically requires particles of micrometre rather than nanometre sizes, but nevertheless many mineral products have always contained a significant proportion of nano and near-nano dimensioned particles. Over the last few years, Imerys has been busy extracting and processing these for a range of new properties and applications. Examples include a toughening agent for clear coatings, where nano size is needed to achieve the clarity and transparency required for the most demanding applications, and microcapsules made from a polymer/mineral nanocomposite which protect their precious cargo of active ingredients from their surroundings and release them exactly when and where they are needed. And the great thing about using particles extracted this way is that we know they’ve been a safe, tried and tested part of everyday materials for centuries, so there’s no need to fear any unseen health risks from their use.
So how, you might ask, can an industry that extracts minerals by the millions of tonnes be called green? Take a look around you, and consider the fact that the things you see are made up from raw materials, and if these can’t be grown they have to be dug out of the ground. So it’s not whether we mine materials, but what they are, how we do it and how we use them that counts. An example: the conventional role of minerals in petroleum-based plastics is to reinforce and stiffen them, reducing the amount of polymer needed for a given task, and achieving the goals of lower cost and sometimes even lower weight. Do the sums, and you find that, more often than not, this reduces the carbon footprint of the product as well.
It doesn’t stop there; Imerys is currently working with UK partners on minerals that will raise the performance of the new generation of bioplastics to the point where they can take over from the conventional ones made from oil. Add in the fact that the minerals simplify and markedly speed up the moulding and processing steps, and the potential is clear.
Finally, at the end of a product lifecycle the mineral components are relatively easy to recover, as they will survive combustion and other high temperature processes needed to purify mixed wastes. Imerys has already developed specialist materials made from sources as diverse as broken glass bottles and the mountains of sludge created by paper recycling. So take a new look at natural minerals, and realise the potential that Imerys has already begun to unlock.
Further information: www.imerys.com