Infrared Spectroscopic Determination of Lactide Concentration in Polylactide:  An Improved Methodology

Braun, Birgit; Dorgan, John R.; Dec, Steven F.

doi:10.1021/ma061922a

Cited by 68 publications

(62 citation statements)

References 31 publications

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“…( Figure 1B) 25 , ensuring the absence of unreacted monomer in the materials. Six polymers were prepared: two each for linear, 4-armed star and 6-armed star architecture (Table 1).…”

Section: Synthesis Of Linear and Star Pdlla And Film Preparationmentioning

confidence: 99%

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

et al. 2017

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This study focuses on the comparative evaluation of star (branched) and linear poly(L,D-lactic acid) (PDLLA) as degradable materials employed in controlled release.The polymers were prepared via ring-opening polymerization initiated by decanol (linear), pentaerythritol (4-armed star) and dipentaerythritol (6-armed star), and processed both in the form of films and nanoparticles. Independently on the length or number of their arms, star polymers degrade slower than linear polymers, possibly through a surface (vs. bulk) mechanism Further, the release of a model drug (atorvastatin) followed a zero-order-like kinetics for the branched polymers, and a first order kinetics for linear PDLLA. Using NHOst osteoblastic cells, both linear and star polymers were devoid of any significant toxicity and released atorvastatin in a bioavailable form; cell adhesion was considerably lower on star polymer films, and the slower release from their nanoparticles appeared to be beneficial to avoid atorvastatin overdosing.

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“…( Figure 1B) 25 , ensuring the absence of unreacted monomer in the materials. Six polymers were prepared: two each for linear, 4-armed star and 6-armed star architecture (Table 1).…”

Section: Synthesis Of Linear and Star Pdlla And Film Preparationmentioning

confidence: 99%

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

et al. 2017

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“…2). There was not any peak at 935 cm −1 , which is characteristic for unreacted monomer of lactide [25]. Characteristic peaks were observed for the same wavenumbers for 2b and 4b PLAs.…”

Section: Polymers Synthesis and Characterisationmentioning

confidence: 81%

Influence of macromolecular structure of novel 2- and 4-armed polylactides on their physicochemical properties and in vitro degradation process

Choińska

Muroya²,

Święszkowski

et al. 2016

J Polym Res

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The objective of this study was to analyse how macromolecular structure of polylactides influences their properties and degradation rate. To achieve this, novel 2-and 4-armed PDLLA and PLLA (noted as 2b and 4b) were synthesized by ring-opening method. 1,4-butanediol and pentaerythritol were used as initiators and stannous octoate was used as catalyst. The obtained polymers were investigated in terms of molecular weight by size exclusion chromatography, thermal properties by differential scanning calorimetry and thermogravimetry, and hydrophilicity by the contact angle measurements. The in vitro degradation test was carried out in PBS solution at 37°C by means of the mass loss, water uptake, molecular weight and thermal properties changes. The branched polylactides including 2bPDLLA, 4bPDLLA, 2bPLLA and 4bPLLA were successfully synthesized and the average molecular weights were around 40-45 kDa. The numbers of arms in each polymer just slightly influenced the thermal properties and the contact angle. The crystallinity of 4bPLLA was 23 %, whereas for 2bPLLA it was 41 %. The degradation rates of both 2b and 4bPLLA were similar and the degradation process was similar only during first 7 weeks. After this period, the degradation rate of 4bPDLLA increased. Consequently, thermal properties and degradation profiles of the branched polymers would depend on plural factors, such as chain length and crystallinity in branched structure.

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“…For the quantization of the lactide monomer amount in the product of the polymerization reaction and its ratio to PLA as a main and required product, Beer's law can be implemented with the aid of infrared spectroscopy. According to Beer's law, [23] the absorbance of the infrared light at a specific wavelength a(λ) is proportional to the product of the concentration (c) of the vibrating bond in the sample (mol L −1 ), and the sample thickness l (cm) through a material constant that represents the molar absorptivity e(λ) (L cm…”

Section: Fourier Transform Infrared Spectroscopy (Ftir)mentioning

confidence: 99%

“…[23] It is important to eliminate the dependence of absolute concentration on infrared absorption, which is possible in binary mixtures if the intensity of a characteristic wavelength ( 1 ) for one component can be normalized by the signal at a wave number ( 2 ) shared by both compounds.…”

Section: Fourier Transform Infrared Spectroscopy (Ftir)mentioning

confidence: 99%

Solution-based synthesis of a four-arm star-shaped poly(L-lactide)

Eldessouki

Buschle‐Diller

Gowayed

2016

Designed Monomers and Polymers

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The mechanical properties of biocompatible poly(L-lactide) (PLA) could be dramatically enhanced by cross-linking and interesting network structures might be achieved via the formation of branched and star-shaped structures prior to such cross-linking. However, the synthesis of a four-armed starshaped PLA is limited to bulk melt polymerization at relatively high temperatures that may degrade the monomer and render the reaction kinetics difficult to control. In this work, a solution-based polymerization approach is introduced with dimethylformamide as the solvent for the initiator and all other reactants. Varying the reactant concentrations and reaction temperature, four-arm PLA star structures were produced in solution and their properties were analyzed. The progress of the polymerization reaction was studied using the 1 H NMR and Fourier transform infrared spectroscopy. The quantitative evaluation of the monomer conversion was discussed on theoretical basis. The thermal properties and the crystallinity of the product polymers were evaluated using differential scanning calorimetry. Results indicate polymerization and cross-linking of the four-armed PLA were successful. The introduced solution-based method could open venues for better controlled and more economic reactions of star-shaped and cross-linked PLA.

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Infrared Spectroscopic Determination of Lactide Concentration in Polylactide: An Improved Methodology

Cited by 68 publications

References 31 publications

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

The Effect of Branching (Star Architecture) on Poly(d,l-lactide) (PDLLA) Degradation and Drug Delivery

Influence of macromolecular structure of novel 2- and 4-armed polylactides on their physicochemical properties and in vitro degradation process

Solution-based synthesis of a four-arm star-shaped poly(L-lactide)

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