Hydrolytic Degradation of Polylactic Acid Fibers as a Function of pH and Exposure Time

Abstract

Polylactic acid (PLA) is a widely used bioresorbable polymer in medical devices owing to its biocompatibility, bioresorbability, and biodegradability. It is also considered a sustainable solution for a wide variety of other applications, including packaging. Because of its widespread use, there have been many studies evaluating this polymer. However, gaps still exist in our understanding of the hydrolytic degradation in extreme pH environments and its impact on physical and mechanical properties, especially in fibrous materials. The goal of this work is to explore the hydrolytic degradation of PLA fibers as a function of a wide range of pH values and exposure times. To complement the experimental measurements, molecular-level details were obtained using both molecular dynamics (MD) simulations with ReaxFF and density functional theory (DFT) calculations. The hydrolytic degradation of PLA fibers from both experiments and simulations was observed to have a faster rate of degradation in alkaline conditions, with 40% of strength loss of the fibers in just 25 days together with an increase in the percent crystallinity of the degraded samples. Additionally, surface erosion was observed in these PLA fibers, especially in extreme alkaline environments, in contrast to bulk erosion observed in molded PLA grafts and other materials, which is attributed to the increased crystallinity induced during the fiber spinning process. These results indicate that spun PLA fibers function in a predictable manner as a bioresorbable medical device when totally degraded at end-of-life in more alkaline conditions.

E-glass/kenaf fibre reinforced thermoset composites fiiled with MCC and immersion in a different fluid

“…Meanwhile, the speed of the reaction depends on the chemistry, solubility, acidity, and oxidation–reduction of each compound 3 . In terms of pH as a degradation medium, neutral pHs have the highest breaking strength of polymer bonds while low and high pHs cause rapid degradation to occur 54 . The matrix degradation observed on the surfaces seen in Figs.…”

Fiber Glass/Kenaf Reinforced Thermoset Composite with Microcrystalline Cellulose as Filler in a Different Fluid Immersion

“…[3]. The effect of pH as a degradation medium was found to have the highest breaking strength of polymer bonds at neutral pH, and rapid degradation occurred at low and high pH [55]. The degradation of the matrix found on the surface of the samples in Fig.…”

3D printing polylactic acid polymer-bioactive glass loaded with bone cement for bone defect in weight-bearing area

“…This phenomenon may result from the interaction of degradation products of PLA and BG. After the degradation of pure PLA, the local internal environment became acidic, which resulted in the decrease in the degradation rate ( Vaid et al, 2021 ). The degradation products of BG are alkaline ( Daskalakis et al, 2022 ), which has an acid-base neutralization effect on the local internal environment, maintains the steady-state of the internal environment, and is conducive to the continuous occurrence of degradation.…”