Nanocomposites

The incorporation of nanoscale filling materials into polymers is an intensive work in progress. The aim is an improvement and optimization of the properties of mass-produced and high-tech-plastics. A commercial example is a Durethan?-film consisting of PA and clay offered by Bayer, that has a higher gas barrier than usual PA. Depending on the application, Clay, double-layered hydroxid or spherical particles (aerosiles) are interesting filler materials.
For achieving a nanoscale dispersion, the particles must have a optimal compatibility with the polymer matrix. Therefore, a specific organic modification of the fillers surface or a bonding agent is often required. It is possible to produce high transparent nano-composites by using filler materials, which have a nanoscale lateral extension in all 3 dimensions.

As already mentioned, good results are achieved by producing PA-clay-nano-composites, but there are still problems to incorporate nano-particles in polyester. One problem is the obtained water that inhibits the chain growth.

In-situ polymerisation/polycondensation in the presence of nanofillers

We are working on solutions for efficient incorporation of nano-particles into polyester-materials in order to improve important parameters like gas-barrier and uv-absorption. Using these materials for films and bottles could be very interesting for the packaging industry.
An approach is the in-situ polymerisation/polycondensation. The adequate filler-material is dispersed in the monomer and dosed to the reaction at a determined conversion. In this way, the stoichiometric relations are easier to adjust, so that it is possible to obtain high average molecular weights.
The search after an appropriated (reactive) modifier and the development of effective synthesis processes is the focus of our studies.

In addition to the in-situ reaction, we are able to produce nano-composites by melt compounding in a twin-screw extruder.
Furthermore, we have experiences with the production of nanoscale-cured melamine resin in suspension.

More expected effects:

• Improvement of the mechanical properties (tensile strength, e-modulus)
• Increasing of the thermal stability
• Improved gas barrier
• Faster nucleation
• Improved fire resistance

Offer

• Chemical modification of the surface of nano-particles
• Development of nano-composites by in-situ-reaction:
  
  Batch-process for:
  • polyester
  • polyamide 6.6
  
  Reactive extrusion for:
  • polyamide 6
  • PLA
  
  
• Development of nano-composites by melt-compounding in a twin-screw extruder
• Characerisation of the products by:
  
  
  • REM /TEM
  • Viscometry
  • GPC
  • DSC/TGA
  • Colorimetry according to CIE-LAB-system
  • Rheometric measuring
  • Zeta-potential