Volume 8 - Dissertation Maria Sonnenberg

Maria Sonnenberg


Interaction of polycarbonate melt with mold surfaces as a cause of deposit formation in plastics processing machines.

Publication typeDissertation
Pages144 pages
Format21 x 14,8 cm
Price45,80 € / 57,30 SFr
Publication date2019
Published byShaker Publishing Ltd.


In this dissertation, the mechanisms of coating and speck formation were fundamentally investigated using polycarbonate as an example. In addition to the topographical influences (cavities and roughness), the interactions between the metallic surface and the polymer were analyzed using surface-sensitive measurement methods. In addition to the analytical investigations, laboratory tests (syntheses) as well as extrusion tests were carried out on a laboratory scale. Diffusion of metal ions (iron and chromium ions) into the polymer melt was demonstrated. A subsequent interaction between polymer and metal ions was also investigated. The possible degradation of polycarbonate in plastics processing machines was specifically analyzed using a miniextruder and degradation experiments. It was shown that temperature has the greatest influence on degradation compared to residence time and speed. Finally, a possible mechanism as well as a list of requirements for avoiding or reducing the formation of deposits was formulated.