Surface Modification Changes the Degradation Process and Degradation Product Pattern of Polylactide

Abstract

The effect of surface modification on the degradation process and degradation product patterns of degradable polymers is still a basically unexplored area even though a significant effect can be expected. Polylactide (PLA) and PLA grafted with acrylic acid (PLA-AA) were, thus, subjected to hydrolytic degradation, and water-soluble degradation products were determined by electrospray ionization-mass spectrometry (ESI-MS) after different time periods. Low molar mass compounds migrated from surface-grafted PLA already during the first 7 days at 37 degrees C, while it took 133 days in the case of nongrafted PLA before any low molar mass compounds were detected in the aging water. In addition, the degradation product pattern of surface-grafted PLA showed significant variation as a function of hydrolysis time with the evolution of short and long AA-grafted lactic acid oligomers as well as plain lactic acid oligomers after different time periods. The degradation product pattern of plain PLA consisted of lactic acid and its oligomers with up to 13 lactic acid units. Surface grafting, thus, changed the degradation product patterns and accelerated the formation of water-soluble degradation products.

Crystallization Study and Comparative in Vitro–in Vivo Hydrolysis of PLA Reinforcement Ligament

“…This can also explain the low weight loss that is recorded at the initial 15–20 days of hydrolysis. The high molecular weight of used PLA for the preparation of reinforcement ligament or its surface hydrophobicity could be responsible for such behavior [43]. Fukuzaki and coworkers found that the molecular weight reduction of high molecular weight L-lactide/glycolide copolymers becomes higher only after a certain time of hydrolysis [39].…”

Assessing the Degradation Profile of Functional Aliphatic Polyesters with Precise Control of the Degradation Products

“…These peaks correspond to previously reported degradation products of PLA consisting of LA oligomers with up to five repeating units terminated by hydroxyl and carboxyl end groups. [26] The most prominent peak was however, still that due to PBM acid . The higher relative intensities of degradation products originating from PBM also supports the hypothesis that the PLLA-PBM-PLLA triblock copolymer degrades by an initial hydrolysis in the PBM middle block with subsequent preferred degradation of the exposed PBM blocks in the PBM-PLLA diblock copolymers thus formed.…”

“…[3,25] We have also demonstrated that electrospray ionization mass spectrometry (ESI-MS) is a powerful tool to identify the oligomers released during degradation which are also a potential source of cytotoxicity. [26] The aim of this present work was to develop a desired degradation profile of modified aliphatic polyesters with precise control of the amount of acidic degradation products released. The homopolymer of PBM and derivatives thereof were thus subjected to hydrolytic degradation and, in particular, the release of monomeric degradation products and changes in pH were assessed.…”

Poly(lactide)-g-poly(butylene succinate-co-adipate) with High Crystallization Capacity and Migration Resistance

“…However, when more acrylated PEG was grafted, the crystallinity decreased. In addition to crystallization control, branching modification provides an efficient approach to increase polymer melt strength [13], improve the interfacial adhesion between PLA and additives [14], and tune degradability and degradation products [15]. Therefore, a good combination of plasticization and nucleation could significantly improve the nucleation and crystal growth of PLA [16,17], mitigate the brittleness and adjust the degradation products pattern of PLA [18].…”