Enhancing the Hydrolytic Stability of Poly(lactic acid) Using Novel Stabilizer Combinations
Commercially available poly(lactic acid) exhibits poor hydrolytic stability, which makes it impossible for use in durable applications. Therefore, a novel hydrolysis inhibitor based on an aziridine derivative as well as a novel stabilizer composition, containing an aziridine derivative and an acid s...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-02-01
|
| Series: | Polymers |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4360/16/4/506 |
| _version_ | 1797297119874252800 |
|---|---|
| author | Jannik Hallstein Elke Metzsch-Zilligen Rudolf Pfaendner |
| author_facet | Jannik Hallstein Elke Metzsch-Zilligen Rudolf Pfaendner |
| author_sort | Jannik Hallstein |
| collection | DOAJ |
| description | Commercially available poly(lactic acid) exhibits poor hydrolytic stability, which makes it impossible for use in durable applications. Therefore, a novel hydrolysis inhibitor based on an aziridine derivative as well as a novel stabilizer composition, containing an aziridine derivative and an acid scavenger, were investigated to improve the hydrolytic stability. To evaluate the stabilizing effect, the melt volume rate (MVR) and molecular weight were monitored during an accelerated hydrolytic aging in water at elevated temperatures. Temperatures were selected according to the glass transition temperature (~60 °C) of PLA. It was shown that the novel hydrolysis inhibitor as well as the novel stabilizer composition exhibited excellent performance during hydrolytic aging, exceeding commercially available alternatives, e.g., polymeric carbodiimides. A molecular weight analysis resulted in a molecular weight decrease of only 10% during approximately 850 h and up to 20% after 1200 h of hydrolytic aging, whereas poly(lactic acid) stabilized with a commercial polycarbodiimide revealed comparable molecular weight reductions after only 300 h. Furthermore, the stabilization mechanism of the aziridine derivative alone, as well as in the synergistic combination with the acid scavenger (calcium hydrotalcite), was investigated using nuclear magnetic resonance (NMR) spectroscopy. In addition to an improved hydrolytic stability, the thermal properties were also enhanced compared to polymeric carbodiimides. |
| first_indexed | 2024-03-07T22:16:38Z |
| format | Article |
| id | doaj.art-1fa372bb882f46218cd2644a8c6c7544 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-07T22:16:38Z |
| publishDate | 2024-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-1fa372bb882f46218cd2644a8c6c75442024-02-23T15:32:17ZengMDPI AGPolymers2073-43602024-02-0116450610.3390/polym16040506Enhancing the Hydrolytic Stability of Poly(lactic acid) Using Novel Stabilizer CombinationsJannik Hallstein0Elke Metzsch-Zilligen1Rudolf Pfaendner2Fraunhofer Institute for Structural Durability and System Reliability LBF, Division Plastics, 64289 Darmstadt, GermanyFraunhofer Institute for Structural Durability and System Reliability LBF, Division Plastics, 64289 Darmstadt, GermanyFraunhofer Institute for Structural Durability and System Reliability LBF, Division Plastics, 64289 Darmstadt, GermanyCommercially available poly(lactic acid) exhibits poor hydrolytic stability, which makes it impossible for use in durable applications. Therefore, a novel hydrolysis inhibitor based on an aziridine derivative as well as a novel stabilizer composition, containing an aziridine derivative and an acid scavenger, were investigated to improve the hydrolytic stability. To evaluate the stabilizing effect, the melt volume rate (MVR) and molecular weight were monitored during an accelerated hydrolytic aging in water at elevated temperatures. Temperatures were selected according to the glass transition temperature (~60 °C) of PLA. It was shown that the novel hydrolysis inhibitor as well as the novel stabilizer composition exhibited excellent performance during hydrolytic aging, exceeding commercially available alternatives, e.g., polymeric carbodiimides. A molecular weight analysis resulted in a molecular weight decrease of only 10% during approximately 850 h and up to 20% after 1200 h of hydrolytic aging, whereas poly(lactic acid) stabilized with a commercial polycarbodiimide revealed comparable molecular weight reductions after only 300 h. Furthermore, the stabilization mechanism of the aziridine derivative alone, as well as in the synergistic combination with the acid scavenger (calcium hydrotalcite), was investigated using nuclear magnetic resonance (NMR) spectroscopy. In addition to an improved hydrolytic stability, the thermal properties were also enhanced compared to polymeric carbodiimides.https://www.mdpi.com/2073-4360/16/4/506poly(lactic acid)hydrolytic degradationaziridineshydrolysis inhibitorsacid regulators |
| spellingShingle | Jannik Hallstein Elke Metzsch-Zilligen Rudolf Pfaendner Enhancing the Hydrolytic Stability of Poly(lactic acid) Using Novel Stabilizer Combinations Polymers poly(lactic acid) hydrolytic degradation aziridines hydrolysis inhibitors acid regulators |
| title | Enhancing the Hydrolytic Stability of Poly(lactic acid) Using Novel Stabilizer Combinations |
| title_full | Enhancing the Hydrolytic Stability of Poly(lactic acid) Using Novel Stabilizer Combinations |
| title_fullStr | Enhancing the Hydrolytic Stability of Poly(lactic acid) Using Novel Stabilizer Combinations |
| title_full_unstemmed | Enhancing the Hydrolytic Stability of Poly(lactic acid) Using Novel Stabilizer Combinations |
| title_short | Enhancing the Hydrolytic Stability of Poly(lactic acid) Using Novel Stabilizer Combinations |
| title_sort | enhancing the hydrolytic stability of poly lactic acid using novel stabilizer combinations |
| topic | poly(lactic acid) hydrolytic degradation aziridines hydrolysis inhibitors acid regulators |
| url | https://www.mdpi.com/2073-4360/16/4/506 |
| work_keys_str_mv | AT jannikhallstein enhancingthehydrolyticstabilityofpolylacticacidusingnovelstabilizercombinations AT elkemetzschzilligen enhancingthehydrolyticstabilityofpolylacticacidusingnovelstabilizercombinations AT rudolfpfaendner enhancingthehydrolyticstabilityofpolylacticacidusingnovelstabilizercombinations |