Study of bioresorbable polymers thermal stability for fiber production

M.N. FERRACE; F. MONTINI BALLARIN

Mar del Plata

Congreso; XII Latin-American Congress of Artificial Organs and Biomaterials; 2023

INTEMA - LABOATEM

Melt Electrospinning Writing (MEW) is an additive manufacturing technique that involve the deposition of polymer fibers to create 3D- structures. It uses a heated nozzle to extrude anddeposit the molten polymer by applying an high voltage electric field. Previous studies on traditionalelectrospinning of poly(ε-caprolactone) (PCL) without heating showed polymer degradation. Understanding the thermal stability of the polymer during its processing is of great importance. The aim of this work is to analyze changes in relative molecular weight distribution and polydispersities of PCL in different heating cycles using gel permeation chromatography (GPC). Melt PCL samples were processed or not by melt-electrospinning at 140°C with an electric field of 12 kV for 1-3 cycles. Samples from the different heating cycles were analysed by GPC in triplicates. Although, differences in apparent molecular weights and polydispersities were observed at 0, 1, 2, 3, 4, 8 and 16 hours of heating at 90°C (M0-M6), it is believe these correspond to the variability of the characterization technique. No significant difference (p>0.05) were observed when number averagemolecular weight (Mn) were analyzed for those heating cycles compared with unheated sample. However, a significant difference (p>0.05) at Mn, Mw and Mz was seen for the simple heated during 4 hours above at 90°C. Moreover, a decrease in molecular weights (Mw, Mz) of samplesprocessed by MEW at 140°C was observed compared to those only treated by heating at 90°C and the unheated sample (p>0.05). These results indicate some degree of degradation in PCL chains during successive processing cycles. This behavior was also observed for solution electrospinning processing-. Differences in the appearance and surface of the fibers obtained from single and multiple processing cycles are noticeable. A synergistic effect due to melt processing and the high voltage electrical field applied to the polymer could be the cause of the observed degradation. Thermal degradation is an important aspect to consider when multiple heating cycles are implemented. Understanding the behavior of the polymer under an applied electric field is crucial.This becomes particularly relevant in the production of fibers using the MEW technique, as there is a dual contribution to degradation. Due to the difference in processing temperature with respect to heating temperature, the contributions cannot be separated.