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KW - Poly(ethylene glycol) poly(L-lactic acid)

KW - Poly(L-lactic acid)

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Synthesis of Poly-(L-Lactic Acid) - Rice University

The copolymer poly(D,L-lactide-co-glycolide) is one of the most interesting polymers for medical applications. This interest is justified by the fact that it is bioreabsorbable, biocompatible and non-toxic, while its degradation kinetics can be modified by the copolymerization ratio of the monomers. In this study, copolymers were synthesised at 175˚C by opening the rings of the cyclic dimers of the D,L-lactide and glycolide monomers in the presence of stannous octoate initiator and lauryl alcohol co-initiator. The application of vacuum to the reaction medium, coupled with adequate stirring, is essential for obtaining good results. The following analytical techniques were used to characterise the synthesised copolymers: Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Nuclear Magnetic Resonance Spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Both the input monomers and the reaction products were analysed. Important characteristics, such as melting temperature, glass transition temperature, thermal stability, chemical composition and the ratio of the monomers in the synthesised copolymer, were obtained from these analyses. These results helped to infer the absence of residual monomers in the synthesised copolymers.

T1 - Synthesis and properties of high MW Poly(D,L-lactic acid)s by direct thermal condensation

AB - Synthesis of poly(L-lactic acid) typically requires a long process time with the use of tin octoate as a catalyst. In this study microwave-assisted polymerization of lactic acid has been studied both with the aid and without the aid of tin octoate catalyst. While the presence of tin octoate assists in the polymerization process, it is not a pre-requisite to polymerization with microwaves. Molecular masses in excess of 25 kDa were possible over process times as little as 2.5 h without the need for a controlled environment. Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and gel-permeation chromatography were used to follow the polymerization process. Microwave-assisted polymerization of lactic acid to yield poly(L-lactic acid) has been shown to be a viable and quicker alternative to tradition approaches to the synthesis of poly(L-lactic acid).

Synthesis of Poly-(L-Lactic Acid) Part I - Chemical Synthesis

T1 - Synthesis of pluronic F88/poly(L-lactic acid) block copolymers and preparation of vesicles

AB - Thermoplastic hydrogels of alternating multiblock copolymers, consisting of poly(ethylene glycol) (PEG) and poly(L-lactic acid) (PLLA), were synthesized. Dicarboxylated oligomeric PLLAs were synthesized by the condensation reaction of L-lactic acid in the presence of succinic acid. Changing the feed ratio of L-lactic acid to succinic acid controlled PLLA molecular weights. Alternating multiblock copolymers with different block lengths of PEG and PLLA were obtained from the polycondensation reaction between PEG and dicarboxylated-PLLA in the presence of dicyclohexyl carbodiimide and N-dimethyl aminopyridine as catalysts. The chemical compositions of dicarboxylated PLLAs and multiblock copolymers were verified by 1H-NMR and FT-IR, and the molecular weight and distribution were measured by gel permeation chromatography. DSC thermograms showed that there existed a high degree of phase mixing, as well as microphase separation in the multiblock copolymer, demonstrated by a large T(g) peak from the amorphous phase-mixing domain and a small T(m) peak from crystalline microdomains of the PLLA component. The block copolymers with low molecular weights were water-soluble and clouded at a temperature which is associated with a lower critical solution temperature (LCST) phenomonon. However, the high molecular weight polymers could swell in water and their optical transparency was influenced by temperature. This observation can be attributed to an enhanced hydrophobic interaction between hydrophobic moieties in the polymer chains, caused by an increase in temperature. The weight swelling ratio (absorbed water/polymer) of the polymers was controlled by polymer composition and molecular weight. These block copolymers may offer potential for applications in drug delivery and various other biomedical projects.

N2 - This book describes the synthesis, properties, and processing methods of poly(lactic acid) (PLA), an important family of degradable plastics. As the need for environmentally-friendly packaging materials increases, consumers and companies are in search for new materials that are largely produced from renewable resources, and are recyclable. To that end, an overall theme of the book is the biodegradability, recycling, and sustainability benefits of PLA. The chapters, from a base of international expert contributors, describe specific processing methods, spectroscopy techniques for PLA analysis, and and applications in medical items, packaging, and environmental use.

Poly(lactic acid) Synthesis in Solution Polymerization

N2 - Thermoplastic hydrogels of alternating multiblock copolymers, consisting of poly(ethylene glycol) (PEG) and poly(L-lactic acid) (PLLA), were synthesized. Dicarboxylated oligomeric PLLAs were synthesized by the condensation reaction of L-lactic acid in the presence of succinic acid. Changing the feed ratio of L-lactic acid to succinic acid controlled PLLA molecular weights. Alternating multiblock copolymers with different block lengths of PEG and PLLA were obtained from the polycondensation reaction between PEG and dicarboxylated-PLLA in the presence of dicyclohexyl carbodiimide and N-dimethyl aminopyridine as catalysts. The chemical compositions of dicarboxylated PLLAs and multiblock copolymers were verified by 1H-NMR and FT-IR, and the molecular weight and distribution were measured by gel permeation chromatography. DSC thermograms showed that there existed a high degree of phase mixing, as well as microphase separation in the multiblock copolymer, demonstrated by a large T(g) peak from the amorphous phase-mixing domain and a small T(m) peak from crystalline microdomains of the PLLA component. The block copolymers with low molecular weights were water-soluble and clouded at a temperature which is associated with a lower critical solution temperature (LCST) phenomonon. However, the high molecular weight polymers could swell in water and their optical transparency was influenced by temperature. This observation can be attributed to an enhanced hydrophobic interaction between hydrophobic moieties in the polymer chains, caused by an increase in temperature. The weight swelling ratio (absorbed water/polymer) of the polymers was controlled by polymer composition and molecular weight. These block copolymers may offer potential for applications in drug delivery and various other biomedical projects.

Poly(lactic acid) (PLAs) is one of the most well-researched and common polymer for biodegradable medical device applications available. All of the research PLA supplied in our catalog is held to the same rigorous quality standards as PLA intended for medical devices.

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  • Synthesis of Poly (L-Lactic Acid) by ..

    T1 - Synthesis and characterization of poly(ethylene glycol)/poly(L-lactic acid) alternating multiblock copolymers

  • “Synthesis of copoly(D,L-lactic acid) ..

    T1 - Poly(Lactic Acid)

  • Synthesis and properties of high MW Poly(D,L-lactic acid…

    BT - Poly(Lactic Acid)

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Poly-L-Lactic Acid - [PDF Document]

6-dimethyl morpholine-2, 5-diode The thermal stability of poly (L-lactic acid-co-glycine-L-methyl lactic acid) is slightly greta text than that of poly(L-lactic acid-co-glycine-L-lactic acid) due to the methyl group.

Synthesis of Biodegradable Poly (L-Lactic Acid): …

The main objective of this study regards the synthesis of one of the most widely used biopolymers in the medical area, the copolymer poly(D,L-lactide-co-glycolide). New conditions suitable for its synthesis are explored. The obtained biopolymers were characterised by using a variety of analytical techniques in order to identify their chemical composition, as well as the final ratio between monomers within the polymeric structure. Analytical techniques have also been employed in order to investigate the biopolymers thermal behaviour as well as to verify the presence or absence of unreacted monomers in the final reaction mixture.

Synthesis and Characteristics of Poly(L-lactic acid …

AB - Ring-opening polymerization of L-lactide using tin(II) 2-ethylhexanoate as a catalyst in the presence of polyethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer (pluronic F88) was used to synthesize an amphiphilic block copolymer. The obtained block copolymer was applied to prepare vesicles for drug carrier applications.

Synthesis and properties of poly(lactic acid). | Docphin

Monomer ratios of 70/30 and 50/50 (D,L-lactide/glycolide) have been used in the syntheses. These proportions have been chosen by considering the degradation time of these copolymers [8]. These are the most commonly used ratios in controlled drug delivery systems.

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