Laser-processing of colloidal nanoparticles and their adsorption on polymer microparticles for laser additive manufacturing


Tim Hupfeld, Technische Chemie I, Universität Duisburg-Essen, Essen, Germany
Stan Gann, Technische Chemie I, Universität Duisburg-Essen, Essen, Germany
Johannes Heberle, Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
Thomas Stichel, Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
Michael Schmidt, Institute of Photonic Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
Bilal Gökce, Technische Chemie I, Universität Duisburg-Essen, Essen, Germany
Stephan Barcikowski, Technische Chemie I, Universität Duisburg-Essen, Essen, Germany

The limited availability of process-specified powder materials poses a major drawback for powder bed fusion of polymers by laser sintering (LS). Flowability, thermal and optical properties as well as melting and resolidification behaviour are crucial factors for the sintering process. Hence, there is a need to develop new metal and polymer powder materials from the laser processability point of view. Additives like nano- and microparticles or fibers can be introduced into the polymer matrix to modify the powder properties. Moreover, they influence the properties of the final part, e.g. crystal structure or the micro- and macrostructure, which directly influences the mechanical properties of the part.

Conventional additivation methods such as ball milling typically come with the disadvantage of agglomeration of the nanomaterial, which makes high filling rates necessary to achieve a sufficient surface dose. Therefore, we introduce a novel colloidal-based additivation process [1] using clean and surfactant-free nanoparticles generated by laser synthesis and processing of colloids [2]. In this route, laser-generated nanoparticles are adsorbed on polymer microparticles directly in a liquid by adjusting the electrostatic interaction between the nanoparticle and polymer surface through pH-variation. Examples for this novel additivation process which leads to a high dispersion of the filler will be given for polyamide (PA12) decorated with a variety of different nanoparticles (e.g. silver, carbon). At the end of the process chain, the powders are also processed via LS.

References
[1] T. Hupfeld, T. Laumer, T. Stichel, T. Schuffenhauer, J. Heberle, M. Schmidt, S. Barcikowski, B. Gökce, Procedia CIRP 2018, 74, 244–248.
[2] D. Zhang, B. Gökce, S. Barcikowski, Chem. Rev. 2017, 117, 3990–4103.

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