The Effects of Washing and Formaldehyde Sterilization on the Mechanical Performance of Poly(methyl Methacrylate) (PMMA) Parts Produced by Material Extrusion‐Based Additive Manufacturing or Material Jetting

Abstract

Nowadays, personalized medical implants are frequently produced through additive manufacturing. As all medical devices have to undergo specific washing and sterilization before application, the effects of a predefined cleaning routine that is available to the clinical institutes, washing with chemical agent and formaldehyde fumigation, on the mechanical behavior of printed parts are examined. Mechanical properties of parts manufactured by fused filament fabrication (FFF) and ARBURG plastic freeforming (APF) using two poly(methyl methacrylate) (PMMA)‐based materials, 3Diakon and CYROLITE MD H12, respectively, are analyzed using flexural and impact tests. An influence of cleaning treatments on the mechanical properties of APF samples is not detected. FFF samples, however, show lower impact strength after washing, but not after sterilization. The fracture surfaces, porosity values, or chemical structure assessed by Fourier‐transform infrared (FTIR) spectroscopy could not explain this decrease. Influence of the cleaning treatments on the material itself is assessed using thin compression‐molded specimens. The influence on the stress–strain curves is negligible, apart from a slight but significant reduction in the yield stress. FTIR spectroscopy and scanning electron microscopy analyses of the fracture surfaces do not show detectable differences among differentially treated samples.

Multiscale characterization of additively manufactured PMMA: the influence of sterilization

“…However, Espalin et al (2010) focused on samples with 50% porosity, to which the difference with the results reported herein (40–115 MPa) is attributed. Finally, Petersmann et al (2022) studied the three-point flexural behavior of 3D printed samples with ±45° raster orientation, reporting a flexural strength of ∼40 MPa. The results of Petersmann et al (2022) are in excellent agreement with the values summarized in the property map in Figure 7.…”

“…Finally, Petersmann et al (2022) studied the three-point flexural behavior of 3D printed samples with ±45° raster orientation, reporting a flexural strength of ∼40 MPa. The results of Petersmann et al (2022) are in excellent agreement with the values summarized in the property map in Figure 7. In all, 3D printing of PMMA with the MEX process has proven a viable pathway to attain a higher degree of customization while achieving the desired mechanical properties.…”

“…However, handling remains a serious issue since it is highly flammable, a carcinogen and may induce structural changes in the polymer (Tipnis and Burgess, 2018; Zhao et al , 2019). Petersmann et al (2022) studied the effects of washing and formaldehyde sterilization on additively manufactured PMMA and found that for FFF printed samples, the effect was more accentuated in the washed batch. Nevertheless, those results were negligible given the small difference with the untreated samples.…”