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2006
Conference Paper
Titel
Improvement of polyurethane and epoxide based adhesives by organically modified nanoparticles
Alternative
Verbesserung von Klebstoffen auf Polyurethan- und Epoxidbasis durch organisch modifizierte Nanopartikel
Abstract
The adhesion and interaction between particle surfaces and the polymer matrix of an adhesive is nothing else than the adhesion of an adhesive on a macroscopic part. The influence of nanoparticles with spherical and sheet like structure on the properties of epoxide and polyurethane based adhesives is presented. The organic surface modification of the particles as well as processing during particle modification and composite preparation are demonstrated to be most important and are discussed with respect to the observed properties. A differentiation is mainly made between surface functionalisation of the particles with reactive and non-reactive groups with respect to the resin. Mechanical properties are strongly influenced by the surface chemistry of the particles. It is demonstrated under which circumstances the lap-shear- strength as well as the peel strength are improved. Nanofillers allow a variety of properties of adhesives and the resulting bonded joints to be improved. In some cases, combinations of properties can be realised which are not possible using conventional raw materials. For example, the use of nanofillers allows the toughness to be considerably increased at constant or even increased rigidity. However, nanofillers are not easy raw materials to use in practice. For any new formulation there is always the issue about whether the desired properties can actually be achieved with nanofillers and, if so what surface modification and processing technology must be adopted. The effects and mechanisms of nanofillers are being ever better understood. However negative experiences still abound due to the fact that nanofillers which have been successfully used for certain applications are simply being tested for other purposes without there being a good fundamental understanding of the specific effects of the nanofillers.