Effects of Steam Heat and Dry Heat Sterilization Processes on 3D Printed Commercial Polymers Printed by Fused Deposition Modeling

Abstract

Fused deposition modeling (FDM), the most widely used additive manufacturing (AM) technology, is gaining considerable interest in the surgical sector for the production of single-use surgical devices that can be tailor-made according to specific requirements (e.g., type of patient surgery, specific shapes, etc.) due to its low cost, ease of access to materials (3D-printing filament), and the relatively low complexity. However, surgical 3D-printing parts should resist sterilization treatments without losing structural, mechanical, and dimensional accuracy. Thus, in this work, 3D-filaments based on poly(lactic acid) (PLA), poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG), and a modified PETG material (CPE) were used to produce 3D-printed parts and further subjected to moist heat (MH) and dry heat (DH) sterilization processes as affordable and widely used sterilization processes in the medical field. The effect of MH and DH was evaluated by performing a complete mechanical, structural, thermal, and morphological characterization before and after both treatments. In general, the moist heat treatment produced a higher degradation of the polymeric matrix of PETG and CPE due to hydrolytic and thermal degradation, particularly affecting the tensile test and flexural properties. For instance, the linear coefficient of thermal expansion (LCTE) before glass transition temperature (Tg) increased 47% and 31% in PETG samples due to the MH and DH, respectively, while it increased 31% in CPE due to MH and was mainly maintained after the DH process. Nevertheless, in PLA, the MH produced an increase of 20% in LCTE value and the DH showed an increase of 33%. Dry heat treatment resulted in being more suitable for medical applications in which dimensional accuracy is not a key factor and there are no great mechanical demands (e.g., surgical guides).

Can Steam Sterilization Affect the Accuracy of Point-of-Care 3D Printed Polyetheretherketone (PEEK) Customized Cranial Implants? An Investigative Analysis

“…However, it should be noted that the tested materials in their study were thermoplastics with low melting point temperatures, such as polylactic acid (PLA), polycarbonates (PC), and acrylonitrile butadiene styrene (ABS). The glass transition temperature (Tg) of polymers predicts how heat-induced sterilization causes chemical and structural changes in polymer properties [ 39 ]. A material with Tg close to steam-sterilization temperature can affect the polymeric chain mobility and its dimensional and mechanical characteristics [ 40 ].…”

Sterilization of Polymeric Implants: Challenges and Opportunities

“…However, the high temperatures may disrupt physical cross-links, melt crystalline domains, and cause undesired physical cross-linking upon cooling, thus presenting unique challenges for temperature-sensitive thermoplastic polymers including thermal responsive shape memory polymers. , The impact of heat sterilization could be catastrophic if critical transition temperatures ( T g , T m ) of the thermosensitive polymers fall within the autoclave temperature range. In addition, steam sterilization may also induce undesired hydrolysis of degradable polymers ,,− or porosity changes of porous hydrogels (e.g., hyaluronic acid hydrogels) due to hydration and swelling . Hydrogel-based coatings or surface-grafted polymers prone to excessive swelling upon hydration will also have to be carefully evaluated for their compatibility with steam autoclave sterilization.…”

Foaming of 3D-Printed PLA/CaCO3 Composites by Supercritical CO2 Process for Sustainable Food Contact Materials

“…Additive manufacturing (AM), commonly referred to as 3D printing, has garnered significant attention in the realm of new product development. This is primarily due to its cost-effectiveness and accessibility, making it a technology that can effortlessly produce affordable and customized products featuring geometrical complex structures [ 1 , 2 ]. Additionally, it includes online co-creation environments in which several documents of already designed products are shared by the “makers” movement [ 3 , 4 ].…”