A Comparative Study on the In Vitro Degradation of PLA Processed by FFF and Film Extrusion

Abstract:

Processing methods strongly influence the degradation behaviour of semi-crystalline polylactic acid (PLA) by affecting its molecular orientation, crystallinity, and micro-and macrostructural features. In our previous study, we presented the changes in the properties of the electrospun PLA fibers during in vitro degradation. Building on these findings, this study compares the degradation of PLA specimens prepared using two bulk processing methods: (i) fused filament fabrication (FFF) 3D printing and (ii) film extrusion. Specimens were incubated in phosphate-buffered saline (pH 7.4) at 37 °C for 1, 3, 7, 28, and 56 days. At each time point, degradation was assessed by tensile testing, differential scanning calorimetry, and weight retention analysis. PLA films exhibited an initial decrease in Young’s modulus, followed by a temporary increase and subsequent decline, whereas FFF specimens maintained mechanical stability for several days before a gradual deterioration. Both specimens showed reduced crystallinity over time, with FFF samples becoming fully amorphous by day 56. Minimal weight change (<1%) indicated that degradation proceeded primarily through structural and morphological changes rather than bulk erosion. Overall, 3D-printed PLA exhibited more stable mechanical properties than extruded PLA films. These findings highlight the significant impact of the processing route on PLA degradation, guiding the optimization of PLA performance in biomedical, packaging, and sustainable material applications.

• Periodical: Materials Science Forum (Volume 1199)
• Pages: 147-153
• DOI: https://doi.org/10.4028/p-RK4zD8
• Online since: August 2026
• Authors: Kardo Khalid Abdullah*, Kolos Molnár
• Keywords: 3D Printing, Degradation, Film Extrusion, PLA

References

[1] Wu, Luo, Liu, Li, Zha, Fabricating multifunctional PLA textiles with advanced respiratory detection and environmental safety, Express Polymer Letters 18 (2024) 1265-1276.

DOI: 10.3144/expresspolymlett.2024.94

[2] D.N. Trivedi, F. Munezero, N. Rachchh, Mechanical characterization of hybrid bagasse/eggshell/e-glass fiber-based polyester composite, Periodica Polytechnica Mechanical Engineering 68(2) (2024) 130-140.

DOI: 10.3311/PPme.22963

[3] Wu, Wang, Wu, Gu, Modified poly(ε-caprolactone) with larvae protein environmentally friendly nanofiber: Assessment of interface properties and characterization, Express Polymer Letters 18 (2024) 835-850.

DOI: 10.3144/expresspolymlett.2024.62

[4] K.K. Abdullah, K. Molnár, Current trends and future prospects of integrating electrospinning with 3D printing techniques for mimicking bone extracellular matrix scaffolds, Journal of Polymer Science 63(6) (2025) 1481-1504.

DOI: 10.1002/pol.20241010

[5] K.K. Abdullah, K. Molnár, A novel air-flow electrospinning setup for controlling fiber distribution and morphology, Solid State Phenomena 371 (2025) 37-44.

DOI: 10.4028/p-piso85

[6] N.K. Kalita, M.K. Nagar, C. Mudenur, A. Kalamdhad, V. Katiyar, Biodegradation of modified Poly (lactic acid) based biocomposite films under thermophilic composting conditions, Polymer Testing 76 (2019) 522-536.

DOI: 10.1016/j.polymertesting.2019.02.021

[7] K.K. Abdullah, K. Molnár, Enhancing crystallinity of electrospun polylactic acid fibers: insights into formation mechanisms and property modulation–a review, Macromolecular Materials and Engineering (2025) e00368.

DOI: 10.1002/mame.202500368

[8] W. Limsukon, M. Rubino, M. Rabnawaz, L.-T. Lim, R. Auras, Hydrolytic degradation of poly(lactic acid): Unraveling correlations between temperature and the three phase structures, Polymer Degradation and Stability 217 (2023) 110537.

DOI: 10.1016/j.polymdegradstab.2023.110537

[9] W. Limsukon, R. Auras, T. Smith, Effects of the three-phase crystallization behavior on the hydrolysis of amorphous and semicrystalline poly(lactic acid)s, ACS Applied Polymer Materials 3(11) (2021) 5920-5931.

DOI: 10.1021/acsapm.1c01080

[10] B. Klimczuk, A. Rudnicka, O. Owczarek, A.K. Puszkarz, G. Szparaga, M. Puchalski, Investigation of the hydrolytic degradation kinetics of 3D-printed PLA structures under a thermally accelerated regime, Materials 17(5) (2024) 1043.

DOI: 10.3390/ma17051043

[11] I. Velghe, B. Buffel, V. Vandeginste, W. Thielemans, F. Desplentere, Review on the degradation of poly(lactic acid) during melt processing, Polymers, 2023.

DOI: 10.3390/polym15092047

[12] R. Sattler, R. Zhang, G. Gupta, M. Du, P.-M. Runge, H. Altenbach, R. Androsch, M. Beiner, Influence of crystallization kinetics and flow behavior on structural inhomogeneities in 3D-printed parts made from semi-crystalline polymers, Macromolecules 57(7) (2024) 3066-3080.

DOI: 10.1021/acs.macromol.3c01940

[13] A. Leonés, L. Peponi, M. Lieblich, R. Benavente, S. Fiori, In vitro degradation of plasticized PLA electrospun fiber mats: morphological, thermal and crystalline evolution, Polymers 12(12) (2020) 2975.

DOI: 10.3390/polym12122975

[14] O. Lužanin, V. Gudurić, A. Bernhardt, D. Movrin, L. Damjanović-Vasilić, P. Terek, G. Ostojić, S. Stankovski, Impact of in-process crystallinity of biodegradable scaffolds fabricated by material extrusion on the micro- and nanosurface topography, viability, proliferation, and differentiation of human mesenchymal stromal cells, Polymers 15(6) (2023) 1468.

DOI: 10.3390/polym15061468

[15] Y. Kobayashi, T. Ueda, A. Ishigami, H. Ito, Changes in crystal structure and accelerated hydrolytic degradation of polylactic acid in high humidity, Polymers 13(24) (2021) 4324.

DOI: 10.3390/polym13244324

[16] K.K. Abdullah, K. Molnár, The influence of in vitro degradation on the properties of polylactic acid electrospun fiber mats, Fibers 13(1) (2025) 1-20.

DOI: 10.3390/fib13010001

[17] E. Fischer, H.J. Sterzel, G. Wegner, Investigation of the structure of solution grown crystals of lactide copolymers by means of chemical reactions, Kolloid-Zeitschrift und Zeitschrift für Polymere 251 (1973) 980-990.

DOI: 10.1007/BF01498927