cell-a7-en

In order to see through our project about cellular materials, we first chose to adopt an approach focused on their acoustic properties.

For this, we bought sound insulating materials used in construction industry (polyurethane foams) and for human ear (earplug) in order to characterise them and to understand how they work.

Then, we decided to make the connection with natural cellular materials used in the same cases. Therefore, we studied cork. 

Version Française 

First, we headed towards polyurethane foams in order to study their structure and their acoustic properties.

We bought two foam slabs of 2m x 1.4m to website of the company named “solution-élastomères”.

The first slab is foam called alveolar foam because it has undulations on its surface which enable a better acoustic insulation than plane foam.

The second slab has a plane surface with a waterproof coating for external insulation or for humid environment.

You can find below description of these foams given by the manufacturer in his catalogue.

These materials were delivered at the ENSIACET and financed by the CIRIMAT.

You can see them as we received them in April 2012 : 

Little pieces of theses slabs were cut in order to be observed under SEM or to be used in our mechanical and acoustic experiments and also for a chemical characterisation of polymers.

Version Française 

We chose to study cork because it is a natural soundproofing material.

Indeed in the old days, lawyers' and notaries  office doors were covered with a thick layer of cork to prevent people from hearing important and confidential information from outside. Therefore, nosy people were not able to eavesdrop!

We bought a pack of 100 cork stopper for 22€ in a supermarket to get this material, as shown on the picture just below.

Version Française 

At the same time of the polyurethane foams described in the previous article, we decided to study a cellular material which is used in everyday life.
We thought about a simple and cheap object like earplugs.

We got 8 pairs of earplugs for 7€ . The noise attenuation given by the manufacturer is about 35dB.

Version Française