Prozesstechnische Analyse eines Herstellungsverfahrens zur Erzeugung medizinischer Polyurethan Vliese mittels pneumatischer Zerstäubung

• Process analysis of a manufacturing method for the production of medical Polyurethane nonwovens by using pneumatic atomization

Nadzeyka, Ingo; Steinseifer, Ulrich (Thesis advisor); Schnöring, Heike (Thesis advisor)

Aachen (2021)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2021, Kumulative Dissertation

Abstract

The use of porous polymer materials for vascular prostheses demonstrates promising results. Fleece-like structures out of microfibers can be generated by pneumatic atomization of dissolved polycarbonate urethanes. This is done by atomizing a solution of a suitable solvent and polycarbonate urethane (PCU) via a high volume low pressure nozzle. The created small droplets allow for rapid evaporation of the solvent, so that these droplets are elongated to fine PCU fibers during their movement to the target surface. By using different rotating molds and positioning systems, tubular shapes or open surfaces can be manufactured from the generated microfibers. The developed manufacturing process for these PCU microfibers is described in detail. A comparison with the established technique of electrospinning is done as well. Inevitable problems of this new process are highlighted and possible solutions presented. The suitability of different hardness grades of PCU for the process is investigated. To gain a better understanding of the process, the influence of different basic process parameters onto the process result is researched via the use of a statistical design of experiments. Basic mechanical properties of the manufactured microfiber nonwovens are presented. Due to the planned use of the process for the manufacturing of cardiovascular implants, the time until full evaporation of the solvent plays a key role and is researched within the framework of this thesis. Permeability of the produced microfiber structures for water and blood is explored as well.