Upgrading of the joining area of vibration welded nanocomposites by modifying material, process and part geometry

• Applicant: Professor Dr.-Ing. Alois K. Schlarb
• Subject Area: Plastics Engineering
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 328798306

Thermoplastic polymers are being used in many applications such as packaging and light weight construction due to their low density and good processability. In order to improve various properties, such as optical, conductive or mechanical properties, reinforcement materials are being added. Previous investigations showed how joining processes, vibration welding included, weaken the mechanical properties (of (nano-)composites (especially the toughness by 50%) whereas in comparison they do not for non-reinforced thermoplastics. The main reason is the flow-induced change of orientation of filler and thermoplastic molecules perpendicular to the joining direction as well as a different morphology after cooling compared to injection molded parts. Therefore the joining area is the weakness of welded parts and the potential of nonocomposites can not be exploid at a uniform wall thickness.The project is amied to solve this issue. Therefore three different approaches will be investigated: load path allined reinforcement with carbon nanotubes based on previous investigations showing a beneficial orientation because of their stiffness, the change of morphology by an additional heat treatment after the joining process, and a change of flow direction and therefore orientation in the joining area by changing the joining part geometry.

• DFG Programme: Research Grants