Plastics have good sense
A nose for plastics
Using polymers to seduce our other senses (hearing, smell and taste) is a less obvious and often indirect endeavour. Nevertheless, their role in these areas is not neutral and not unimportant, particularly in relation to our sense of smell. We know that every human being has their own DNA and their own unique fingerprints. We also know that police forces around the world can take those fingerprints and add them to computer databases. However, on the whole, fewer people are aware of the fact that we also have a unique olfactory imprint. Every individual has their own body odour that only certain animals such as dogs are able to recognise. The French gendarmerie is currently investigating the issue and ultimately hopes to create a substantial database. This is a major challenge, because although cross-matching fingerprints and DNA can deliver results with close to 100% accuracy, a significant amount of uncertainty is nevertheless involved. Adding data from olfactory imprints would make the margin of error almost non-existent. Some may consider this an additional means of being kept on record, while others may consider another means of proving innocence. Countless people have been cleared years after the fact as a result of advances in DNA testing.
We all have an olfactory imprint, and it can be collected on a plastic stick. |
The gendarmerie is still experimenting with their new process. Thus, it only asked for volunteers to take part in the project. Odour receptors had to be developed to collect the unique individual odours. This is where polymers come into play, as they are used in the plastic sticks used to collect the odours (although their composition is a closely-guarded secret). The volunteers were asked to rub their hands together for twenty minutes, which is the time required for the sticks to soak up the smell.
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Once collected, the volatile and semi-volatile organic compounds present on the skin are extracted by thermodesorption, analysed and then subjected to statistical processing in order to define each individual’s olfactory imprint. To be continued.
Polymers create the new car smell
Polymers are particularly adept at transmitting odours. Currently, incorporating odorous molecules into plastic objects is easily achieved. The advantage of this technique is its ability to diffuse odours over the long term. A splash of odorant spray would do the trick, but the smell dissipates in a few minutes, and at best in a few hours. This technique is used by some car manufacturers who integrate microcapsules containing the new car smell into the plastics of their dashboards. It was found that drivers like the smell and that it gives them a certain amount of pleasure when sitting behind the wheel.
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Buying a new car is a special moment for our senses, and for our sense of smell in particular. Some manufacturers even incorporate microcapsules containing the “new car smell” into the plastics used in the dashboard |
Although this smell occurs naturally in new vehicles, it usually disappears in just a few days. By chemically reproducing the smell and incorporating it into plastic parts, it can be made to last several months, although it is no longer naturally-occurring at that point.
Purity of sound through plastics
Wood and metal have long been considered the only noble materials able to transmit a pure sound, whether in musical instruments or loudspeakers. However, this belief no longer holds true as a result of advances in plastics over the past decades. Of course, everyone remembers those plastic recorders that delighted many a teenager, but whose sound qualities could not rival those of their wooden counterparts. At the time, plastics provided access to beginners’ instruments at very low prices. In fact, that was their sole advantage at the time.
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For some time now, polymers and composites have proven their ability to produce sound. Few manufacturers still use ebony, for instance. In the 1950s, they began replacing it with ebonite, particularly for practice instruments. These cheaper instruments were affordable, and learning to play an instrument became accessible to all. It helped matters that the sound they produced was of a satisfactory quality.
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Other polymers were subsequently used, and the very famous Buffet Crampon began selling professional quality clarinets whose bodies were 95% made of recycled passion fruit vine fibre, carbon fibre and epoxy resin. In this case, the aim was not to produce a low-cost instrument, but rather to attain perfection in terms of sound.
This philosophy is also espoused by Kawai, a prestigious Japanese piano maker, a part of whose mechanism is made from ABS (acrylonitrile butadiene styrene). Other, just as high-end brands have managed to replace the traditionally maple soundboard using a new composite made up of carbon fibres, wood fibres and epoxy resin. String instrument makers have also jumped on the bandwagon. As a result, many violins, and the electric models in particular, use resins to reduce their weight and make them more ergonomic. Finally, we would be remiss in not mentioning loudspeakers, and in particular the currently popular portable models whose ABS bodies can perfectly reproduce Hi-Fi sound.
Guaranteed integrity for polymers
It must be admitted that plastics have absolutely no talent in the area of enhancing taste. However, it would be a pity not to evoke food packaging which, although it does not enhance the intrinsic taste of the products it contains, at least has the merit of doing everything possible to avoid altering that taste. This is one of the reasons for which food and cosmetics producers generally opt for polymers when creating their packaging. However, there are other reasons for doing so, as polymers are also the best at blocking bacteria and oxygen which contribute to the rapid deterioration of food and cosmetic products. Using polymers also helps them to prevent waste.
Plastic packaging contributes to combating waste. To date, no better material has been found to act as a barrier against bacteria and oxygen. |