Herstellung von Elastomernanokompositen unter Nutzung von in-situ Synthesestrategien

A variety of different fillers are used to reinforce diene polymers. In some applications silica-based fillers have almost completely replaced carbon blacks. In this manner even more individualized property profiles can be set. However this type of filler or surface modification can be associated with challenges. One of the key challenges is the energy balance. Due to the elevated temperatures required for the silanisation step, the cross-linking system can only be introduced in a further mixing stage. In addition, potentially hazardous quantities of methanol or ethanol may be released during the silanisation step. Furthermore the performance of the silica/silane technology is largely dependent on the polymer matrix and the alkoxy silane. For this reason research was carried out into a new type of composite that attempts to combine these two aspects. A polymer-based surface modification is intended to ensure functionalization and bonding of the filler to the polymer matrix. At the same time the surface modification can be individually adapted to the polymer matrix surrounding the filler. By using in-situ synthesis strategies the particle properties of the filler composite can be adjusted to suit the application. In this way, highly reinforcing fillers can be produced that achieve comparable properties without an additional processing step. The in-situ synthesized filler particles are coated with a low-molecular counterpart of the surrounding polymer matrix. This functionalization effectively prevents intramolecular interactions between the filler particles and ensures improved compatibility. Furthermore, a homogeneous dispersion of the filler can be achieved. In this way, silica-filled natural rubber compounds could become increasingly relevant from a technological point of view. The effectiveness of this filler surface modification no longer depends on the reactivity between the polymer matrix and the sulphur-containing alkoxy silanes. Especially tread compounds for car tyres can be developed on a natural rubber basis using this filler-type. The use of natural rubber enables high mileage while the high silica content ensures a low rolling resistance.