Raman spectra of glycolic acid, l-lactic acid and d,l-lactic acid oligomers

Cassanas, G.; Kister, G; Fabregue, E.; Morssli, M.; Bardet, L.

doi:10.1016/0584-8539(93)80181-9

Cited by 41 publications

(46 citation statements)

References 9 publications

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“…IR and Raman spectra of the compound in aqueous solution, where the compound was in its anionic form (carboxylate), were also reported previously and vibrational assignments for these spectra proposed by Cassanas et al 18,19 The microwave spectrum of lactic acid in the gaseous phase has been studied with aid of double resonance techniques. 20 Selective deuteration in the two hydroxyl groups led to the conclusion that the conformation displaying a hydrogen bond from the a-hydroxyl group to the carbonyl oxygen atom, analogous to the conformational ground state of both glycolic and a-hydroxy isobutyric acids, is the most stable form of lactic acid in the gaseous phase.…”

Section: Introductionmentioning

confidence: 67%

Rotational isomers of lactic acid: first experimental observation of higher energy forms

Borba

Gómez‐Zavaglia

Lapiński

et al. 2004

Phys. Chem. Chem. Phys.

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Lactic acid {2-hydroxypropionic acid [CH(CH 3)OHCOOH]} monomer was studied by matrix isolation FT-IR spectroscopy and molecular orbital calculations undertaken at both DFT(B3LYP)/6-311þþG(d,p) and MP2/ 6-31G(d,p) levels of approximation. The theoretical calculations predicted the conformer (SsC) with the carboxylic group and both the CCOH (alcohol) and O=CCO moieties in a cis configuration as the most stable form. In this conformer, the a-hydroxy hydrogen atom is involved in an intramolecular hydrogen bond with the carbonyl oxygen atom. The second most stable conformer (GskC) also shows a cis carboxylic group and differs from SsC in the CCOH (alcohol) and O=CCO dihedral angles, which are equal to 43.3 and 156.8 respectively. These angles are equal to À51.5 and À149.9 in the third most stable conformer (G 0 sk 0 C). These forms are characterized by showing a relatively weak intramolecular H (alcohol) Á Á ÁO (acid) hydrogen bond. In the AaT conformer, the carboxylic group is trans and the CCOH (alcohol) and O=CCO dihedral angles are 162.2 and 174.1 , respectively. This conformer shows a relatively strong H (acid) Á Á ÁO (alcohol) hydrogen bond. In consonance with the theoretical results, the matrix isolation experiments confirmed the predominance of conformer SsC in argon and xenon matrices, and provide the first experimental evidence of conformers GskC and AaT. Since the barrier for interconversion G 0 sk 0 C $ GskC is only $2 kJ mol À1 , these two conformers are in equilibrium in the matrices and, at low temperature, the population of the less stable G 0 sk 0 C form is too small to enable its observation. Full assignment of the observed spectra was undertaken on the basis of comparison with the theoretical data and temperature variation studies. Water doping of matrices enabled the identification of spectral features due to weakly bound complexes of lactic acid with water.

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Section: Introductionmentioning

confidence: 67%

Rotational isomers of lactic acid: first experimental observation of higher energy forms

Borba

Gómez‐Zavaglia

Lapiński

et al. 2004

Phys. Chem. Chem. Phys.

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“…Vibrational studies on the ring-opening polymerization of L-lactide and D,L-lactide, 10 on L-lactic and D,L-lactic acid oligomers 11 and on the morphology, conformation and configuration of various PLAs 12,13 have been reported. Since lactic acid is a chiral compound, different stereocopolymers can be obtained; high or low molecular weight, semi-crystalline or amorphous, isotactic, syndiotactic or atactic polymers can be synthesized depending on the polymerization method (conditions and starting materials).…”

Section: Pla Homopolymers Vibrational Characterizationmentioning

confidence: 99%

“…15 -18 This progressive increase in nail crystallinity during in vivo implantation was explained considering that the fast-degrading amorphous parts of the polymer leave its crystalline domains with a consequent increase in crystallinity. Moreover, the absence of the bands attributable to low molecular weight degradation products 11,25 in the Raman spectra of the implanted nail [ Fig. 2(A)(b)-(e)] and the in vivo degraded Guidor  membrane [ Fig .1(b)] suggested that the degradation products were easily absorbed by the surrounding tissues.…”

Section: Pla Homopolymers Vibrational Characterizationmentioning

confidence: 99%

Vibrational spectroscopy of polymeric biomaterials

Taddei

Tinti

Fini

2001

J Raman Spectroscopy

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This review highlights the potential of vibrational spectroscopy for investigating the molecular structure of some polymeric materials used in biomedical applications in relation to their biocompatibility. Many types of polymers are used for biomedical purposes; depending on the application, bioresorbable or non-bioresorbable (semi-crystalline or amorphous) polymers are used. Among bioresorbable polymers, we focused on homopolymers and copolymers based on poly(lactic acid), poly(glycolic acid) and poly(ecaprolactone). Being a nondestructive technique, Raman spectroscopy proved particularly suitable for evaluating the molecular structure and crystallinity of bioresorbable polymers and their degradation products. For various biomedical applications, non-degradable semi-crystalline polymers have been widely employed; in this class of polymers, we concentrated on ultra-high molecular weight polyethylene (UHMWPE) used in orthopaedic implants (total hip and knee joints). Vibrational spectroscopy appeared particularly suitable in studying the oxidation and crystallinity of UHMWPE.

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“…As regards the membranes, Figure 11 shows the Raman spectrum of the electrospun TPU mat in comparison with the sonicated MWCNTs suspension one. According to its complex molecular structure, tentative band assignments were made with reference to earlier Raman studies of polyurethanes [28][29][30][31] and are reported in Figure 11. Raman scattering intensity at 862 cm −1 , related to the C-O-C and C-C-C bending, was used as a reference for normalization of all the spectra.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Electrically Conductive Membranes Obtained by Simultaneous Electrospinning and Electrospraying Processes

Roso

Lorenzetti

Boaretti

et al. 2016

Journal of Nanomaterials

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Electrically conductive polyurethane nanostructured membranes have been prepared combining the electrospinning of polymer nanofibers (NFs) with the electrospraying of pristine multiwall carbon nanotubes (MWCNTs) in simultaneous processes. In order to have a better understanding of the distribution of MWCNTs on the surface of the membranes, the optimization of the electrospraying process has been carried out and the distribution of MWCNTs has been evaluated using image texture analysis techniques. Large membranes with a volume resistivity typical of electrostatic discharge materials with a MWCNTs concentration less than 0.3% wt (0.01 mg/cm2) have been obtained and characterized with morphological (SEM and TEM) and spectroscopic (UV-Vis, Raman) techniques.

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Raman spectra of glycolic acid, l-lactic acid and d,l-lactic acid oligomers

Cited by 41 publications

References 9 publications

Rotational isomers of lactic acid: first experimental observation of higher energy forms

Rotational isomers of lactic acid: first experimental observation of higher energy forms

Vibrational spectroscopy of polymeric biomaterials

Electrically Conductive Membranes Obtained by Simultaneous Electrospinning and Electrospraying Processes

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