Self-repairing Materials For Futuristic Buildings

Tag : Repairing Adhesives

This reaction of nature to damage suffered was the starting pointfor the development of self-repairing polymer materials with thecapacity of recovering a good part of the properties lost and withno or with minimal external help. In the case of ceramics ormetallic materials, progress is much slower, being limited toinitial steps.
There are currently two notable self-repairing technologies inpolymer materials: adhesives and thermal encapsulation.
As the name suggests, the first of these involves a series of"stores" of adhesive found distributed in the mosthomogenous manner possible throughout the material, so that whenthe crack reaches one of these nodes the adhesive is secreted,together with a catalyst, and the crack is closed and the materialpolymerised.
There are two variants within this line of technology, depending onwhether adhesive-containing microcapsules or tubes filled withadhesive are employed.
INASMET-Tecnalia has worked on this line in a project undertakenfor the AIRBUS, having managed to produce a series of microcapsulesand distribute them in a polymeric resin. This was a fundamentalstep to finding out the difficulties that might arise in theencapsulation process.
The second method, developed by Bristol University, is a projectfor the ESA, is very similar. The difference lies in the use oftubes rather than microcapsules filled with adhesive.
The thermal method uses a different repair methodology. Thematerial, developed by the University of Sheffield, is a polymericmatrix compound, reinforced with carbon fibres. The polymer matriz,in turn, is made of a solid solution of a thermoplastic polymer andanother thermostable polymer.
The only restriction of the thermostable material is that it has tobe suitable for incorporating these reinforcment fibres into it.The thermoplastic material has greater limitations, limiting itchances of being chosen for use, being highly dependant on thethermostable material used. In this case, when damage is detected,repair is carried out by heating the material with some deviceincorporated into it.
This heating is capable of raising the temperature above that ofthe fusion of the thermoplastic material which, as a result, meltsand flows into the damaged areas so that the cracks are sealed andthe component restored to its former condition. INASMET-Tecnaliahas also worked in this field within the framework of theaforementioned project.
It should be underlined that the development of self-repairingmaterials is still at initial stages and there is a long way to goyet before reaching the desired goal. Nevertheless, the resultsobtained are encouraging.
Apart from participation in this project, INASMET-Tecnalia isworking on a number of research lines related to the growing demandthat is anticipated for self-repairing materials.