L-Lactic acid (L-LA) oligomers (up to the pentamer) were studied by three complementary approaches: vibrational (IR and Raman) and NMR ((1)H and (13)C) spectroscopies and DFT calculations. Vibrational and NMR spectra of L-LA oligomers and poly(L-lactic acid) (PLLA) homopolymer were recorded at room temperature and interpreted. Further insight into the structures (conformations) of the title systems was provided by theoretical B3LYP/6-311++G(d,p) studies. Calculated energies and computed vibrational and NMR spectra of the most stable conformers of L-LA oligomers, together with the experimental vibrational and NMR spectra, enabled the characterization of the preferred conformations adopted by PLLA chains.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jp205033c | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The ring-opening polymerization (ROP) of l-lactide (l-LA) is the main method for synthesizing poly(l-lactide) (PLLA), in which choosing the catalyst is one of the most important parameters. In this work, we focused on the systematic study of catalysts based on p-block elements from period 5, such as indium(iii), tin(ii), tin(iv) and antimony(iii) acetates, which displayed contrasting performances influenced by the oxidation state of the metal center. Analysis of the obtained oligomers by different techniques, including nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), polarized optical microscopy (POM) and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF), revealed the selectivity of each catalyst toward the ROP of l-LA.
View Article and Find Full Text PDFIdentifying carbohydrate-active enzymes of Cutaneotrichosporon oleaginosus using systems biology.
Microb Cell Fact
October 2021
Werner Siemens-Chair of Synthetic Biotechnology (WSSB), Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany.
Background: The oleaginous yeast Cutaneotrichosporon oleaginosus represents one of the most promising microbial platforms for resource-efficient and scalable lipid production, with the capacity to accept a wide range of carbohydrates encapsulated in complex biomass waste or lignocellulosic hydrolysates. Currently, data related to molecular aspects of the metabolic utilisation of oligomeric carbohydrates are sparse. In addition, comprehensive proteomic information for C.
View Article and Find Full Text PDFDevelopment of Inherently Flame-Retardant Phosphorylated PLA by Combination of Ring-Opening Polymerization and Reactive Extrusion.
Materials (Basel)
December 2019
Polymeric and Composite Materials Unit, Materia Nova Research Center, Nicolas Copernic 3, 7000 Mons, Belgium.
In this study, a highly efficient flame-retardant bioplastic poly(lactide) was developed by covalently incorporating flame-retardant DOPO, that is, 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide. To that end, a three-step strategy that combines the catalyzed ring-opening polymerization (ROP) of L,L-lactide (L,L-LA) in bulk from a pre-synthesized DOPO-diamine initiator, followed by bulk chain-coupling reaction by reactive extrusion of the so-obtained phosphorylated polylactide (PLA) oligomers (DOPO-PLA) with hexamethylene diisocyanate (HDI), is described. The flame retardancy of the phosphorylated PLA (DOPO-PLA-PU) was investigated by mass loss cone calorimetry and UL-94 tests.
View Article and Find Full Text PDFPoly(ester amide)s based on (L)-lactic acid oligomers and α-amino acids: influence of the α-amino acid side chain in the poly(ester amide)s properties.
J Biomater Sci Polym Ed
December 2013
Department of Chemical Engineering, University of Coimbra, Polo II, Rua Sílvio Lima, Coimbra 3030-790, Portugal.
Article Synopsis
- Researchers successfully created biodegradable and low cytotoxic poly(ester amide)s (PEAs) using α-amino acids and (L)-lactic acid via interfacial polymerization.
- The type of α-amino acid used significantly affects the properties of the PEAs, with L-phenylalanine increasing glass transition temperature and glycine improving crystallinity.
- The new PEAs showed fast hydrolytic degradation, especially those based on glycine, but had low cytotoxic effects on human fibroblast cells, indicating potential for safe biomedical applications.
Experimental (IR/Raman and 1H/13C NMR) and theoretical (DFT) studies of the preferential conformations adopted by L-lactic acid oligomers and poly(L-lactic acid) homopolymer.
J Phys Chem B
January 2012
Department of Chemistry, University of Coimbra, Coimbra, Portugal.
L-Lactic acid (L-LA) oligomers (up to the pentamer) were studied by three complementary approaches: vibrational (IR and Raman) and NMR ((1)H and (13)C) spectroscopies and DFT calculations. Vibrational and NMR spectra of L-LA oligomers and poly(L-lactic acid) (PLLA) homopolymer were recorded at room temperature and interpreted. Further insight into the structures (conformations) of the title systems was provided by theoretical B3LYP/6-311++G(d,p) studies.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!