Lleida Asensio, Rubén
This final master's project is motivated by the need to find a chemical post-process method for ULTEM™ 9085 parts manufactured by Fused Deposition Modeling (FDM) technology.
ULTEM™ 9085 is the trade name of a thermoplastic polymer in the polyetherimide family. It is a material with promising properties for different industries, especially for the transport industry. Its resistance-to-weight ratio, its FST certification (flame, smoke and toxicity) and the possibility of being printed by FDM, make it a material of both academic and industrial interest.
The post-process to which the ULTEM™ 9085 is subjected is usually the removal of the support necessary for printing, which in this case is a polysulfone. However, this material is removed manually such a task and, depending on the geometries, can be difficult or even practically impossible. For other materials printed by FDM such as polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS), the solution to this problem is using soluble supports in certain solvents, without or minimally altering their properties. However, this solution does not exist for the ULTEM ™ 9085.
Therefore, the main objective of this study is to find a solvent compatible with ULTEM™ 9085 that eliminates the support material from the pieces. To achieve this, solvents that have been previously studied by this research group have been evaluated and, in parallel, have been experimented with new formulations. Throughout the study, different techniques have been used to characterize the solvent and its interaction with the material of interest, to observe and to quantify the effect that this post-process has on the ULTEM™ 9085 parts and on the polysulfone.
After initial solubility tests, it has been found that the best candidate to dissolve the support material is a mixture of aniline with toluene. The proportion and exposure times of both components have been optimized and it has been shown that the most effective solvent contains an aniline percentage between 5% to 20% and is capable of dissolving the support material by slightly altering (<10%) the properties of ULTEM™ 9085 in times less than 60 minutes. Likewise, a method has been found to recover the solvent without altering its composition by a precipitation process of the dissolved support material followed by a distillation.