TY - JOUR AB - While fused deposition modeling (FDM) and other relatively inexpensive 3D printing methods are nowadays used in many applications, the possible areas of using FDM-printed objects are still limited due to mechanical and thermal constraints. Applications for space, e.g., for microsatellites, are restricted by the usually insufficient heat resistance of the typical FDM printing materials. Printing high-temperature polymers, on the other hand, necessitates special FDM printers, which are not always available. Here, we show investigations of common polymers, processible on low-cost FDM printers, under elevated temperatures of up to 160 °C for single treatments. The polymers with the highest dimensional stability and mechanical properties after different temperature treatments were periodically heat-treated between -40 °C and +80 °C in cycles of 90 min, similar to the temperature cycles a microsatellite in the low Earth orbit (LEO) experiences. While none of the materials under investigation fully maintains its dimensions and mechanical properties, filled poly(lactic acid) (PLA) filaments were found most suitable for applications under these thermal conditions. AU - Storck, Jan Lukas AU - Ehrmann, Guido AU - Güth, Uwe AU - Uthoff, Jana AU - Homburg, Sarah Vanessa AU - Blachowicz, Tomasz AU - Ehrmann, Andrea ID - 2015 IS - 14 JF - Polymers KW - additive manufacturing KW - polymers KW - space KW - microsatellites KW - thermal stability KW - dimensions KW - mechanical properties TI - Investigation of Low-Cost FDM-Printed Polymers for Elevated-Temperature Applications VL - 14 ER - TY - JOUR AB - Electrospinning can be used to produce nanofiber mats. One of the often used polymers for electrospinning is polyacrylonitrile (PAN), especially for the production of carbon nanofibers, but also for a diverse number of other applications. For some of these applications—e.g., creation of nano-filters—the dimensional stability of the nanofiber mats is crucial. While relaxation processes—especially dry, wet and washing relaxation—are well-known and often investigated for knitted fabrics, the dimensional stability of nanofiber mats has not yet been investigated. Here we report on the wet relaxation of PAN nanofiber mats, which are dependent on spinning and solution parameters such as: voltage, electrode distance, nanofiber mat thickness, and solid content in the solution. Our results show that wet relaxation has a significant effect on the samples, resulting in a dimensional change that has to be taken into account for nanofiber mats in wet applications. While the first and second soaking in pure water resulted in an increase of the nanofiber mat area up to approximately 5%, the dried sample, after the second soaking, conversely showed an area reduced by a maximum of 5%. For soaking in soap water, small areal decreases between approximately 1–4% were measured. AU - Grothe, Timo AU - Sabantina, Lilia AU - Klöcker, Michaela AU - Juhász Junger, Irén AU - Döpke, Christoph AU - Ehrmann, Andrea ID - 522 IS - 1 JF - Technologies KW - electrospinning KW - filter KW - wet relaxation KW - dimensions KW - polyacrylonitrile (PAN) TI - Wet relaxation of electrospun nanofiber mats VL - 7 ER -