Wrapped in polymers

Food packs, containers, toothpaste tubes, wheels, glue, paints … they are all made of polymers. The world of polymers is infinite and, so, there is a great variety. The majority have been designed for a specific application; given that at times the application might be for a food container and, at others, for the superstructure of a vehicle. The specifications needed in either case are quite different.

Polymers are gigantic molecules, but they are synthesised from small compounds: monomers. In fact, the name of the polymer normally indicates from which monomer it has been synthesised. For example, polystyrene (PS) is obtained from styrene, polyvinyl chloride (PVC) from vinyl chloride, etc.

But not polystyrenes are the same. Depending on the length of the monomer chain or on the mode of synthesis or processing, the final result can vary. Thus, before analysing any polymer, it is necessary to characterise it thoroughly.

Transport properties

At the Chemistry Faculty of the Donostia campus of the University of the Basque Country, the transport properties of polymers, amongst other properties, are being researched. That is, how small molecules (water vapour, oxygen, CO2 and so on) are transported in a polymer.

For example, transparent film to protect foodstuffs is made of polymers. It is essential to know the following: what substances are absorbed by this film, at what rate they are absorbed, at what point does the film become saturated, what is the manner in which these substances are transported through the polymer and, once penetrated the film, how many get to the other side. Apart from these characteristics the permeability of the polymer is also analysed.

In this way, case by case, the transport properties of each polymer is analysed.

Biodegradable polymers

All these theoretical and experimental analyses have one aim: to understand the transport properties of polymers and get to know them better in order to enhance these polymer characteristics. That is, industry will always look for the ideal polymer for its needs, needless to say taking into account price and ease of industrial handling of the polymer.

But from here on in, this search will have to include a feature which, up to now, has not been taken into account: the capacity for degradation. This is due to the fact that polymers degrade very slowly and, on many occasions during this process, compounds are produced which are a danger to nature. This is why, in the coming years legislation will be introduced to ensure that polymers are biodegradable, at least to a certain percentage. One of the objectives of the researchers at the Donostia campus is to start investigating polymers with these characteristics.