POS9-0182
Comparative Analysis of Bulk and Surface Erosion Behaviors in Semi-Crystalline PLLA and Amorphous PDLLA under Accelerated Enzymatic Conditions
Topic
S9. Polymer Technology for Sustainability
When and Where
Sep 30, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Heesuk KIM
Jinhye BAE
Presenter(s)
Jaeyoung Park (BK21 FOUR Department of Materials Science and Engineering, Korea University, Seoul, 02841, Republic of Korea)
Co-Author(s)
Abstract
While polylactic acid (PLA) is extensively used in biomedical applications, stereochemical differences in degradation mechanisms between its optical isomers remain critical for clinical safety and material stability. This study presents a comparative analysis of bulk and surface erosion mechanisms by simultaneously evaluating physicochemical property changes in 2D PLA films and morphological degradation of 3D PLA microparticles under accelerated in vitro enzymatic conditions using Proteinase K and Lipase. Mechanical, thermal, and molecular monitoring of films revealed that semi-crystalline Poly-L-lactic acid (PLLA) undergoes water penetration into amorphous regions, triggering internal chain cleavage and bulk erosion. This disproportionate degradation progressively increased crystallinity (up to 60.3%), ultimately causing sudden catastrophic brittle fracture. In contrast, the random enantiomeric distribution in amorphous Poly-D,L-lactic acid (PDLLA) suppresses crystallization, promoting steady linear reduction in mechanical properties without sudden structural failure—indicative of controlled surface erosion. Morphological analyses via SEM and 3D MicroCT on polymeric microparticles further demonstrated that highly crystalline PLLA particles rapidly shattered into sharp, irregular fragments upon internal structural collapse. Conversely, amorphous PDLLA microparticles featuring a densely packed nanoporous sponge network effectively buffered mechanical stress and enzymatic attack, eroding uniformly layer-by-layer from the exterior while preserving spherical integrity and low aspect ratio throughout degradation. These concurrent evaluations definitively confirm that the amorphous structure of PDLLA, combined with nanoporous architecture, prevents generation of sharp rigid fragments associated with PLLA bulk erosion. Consequently, PDLLA offers superior morphological retention and a stable, biocompatible degradation profile.
