End-Group Evaluation of HEMA Initiated Poly(ε-caprolactone) Macromonomers via Enzymatic Ring-Opening Polymerization

Poly(ε-caprolactone) (PCL) macromonomers comprising acrylate end-functionality were synthesized via enzymatic ring-opening polymerization (eROP) by utilizing commercially availableCandida antarcticaLipase B (CALB), Novozyme-435. 2-Hydroxyethyl methacrylate (HEMA) was purposed to be the nucleophilic initiator in eROP. The side reactions generated due to the cleavage of ester bonds in HEMA and the growing polymer chains were investigated through altering polymerization period, initiator concentration, temperature, and enzyme concentration.1H NMR evaluations showed that minimum quantities of side reactions were in lower temperatures, initiator concentration, enzyme concentration, and lower monomer conversions. Gel permeation chromatography (GPC) results revealed that lower polydispersity along with number-average molecular weight of end-functionalized PCL macromonomers was obtained depending on higher initiator/monomer ratios, lower temperature (60°C), enzyme concentration (100 mg), and/or polymerization time (2 h). Furthermore, 0.1 HEMA/ε-caprolactone (CL) ratio had higher molecular weight than 0.5 HEMA/CL ratio, while keeping a close value of methacrylate transfer, total methacrylate end-groups, and lower polyester transfer.

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A New Green Process for Synthesising High Quality PLLA Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.1377 ◽

2013 ◽

Vol 750-752 ◽

pp. 1377-1380 ◽

Cited By ~ 1

Author(s):

Hui Li Shao ◽

Xian Jue Zhou ◽

Xue Chao Hu

Keyword(s):

Molecular Weight ◽

Ring Opening ◽

Average Molecular Weight ◽

Gel Permeation Chromatography ◽

Ring Opening Polymerization ◽

Green Process ◽

Weight Average Molecular Weight ◽

H Nmr ◽

Ft Ir ◽

C Nmr

Synthesis of Poly(L-lactide) (PLLA) by the ring-opening polymerization (ROP) of L-lactides in supercritical carbon dioxide (SC-CO2) with co-solvent were studied. Effects of kinds of co-solvent on the molecular weight (MW) and the molecular weight distribution (MWD) of the resultant polymers were investigated by the gel permeation chromatography (GPC). The resultant polymers were also characterized with1H NMR,13C NMR and FT-IR. It was found that PLLA with high purity and almost without racemization could be obtained by this technology and the acetone is the best co-solvent for this kind of polymerization. By using stannous octoate as initiator and acetone as co-solvent, PLLA having a weight-average molecular weight (Mw) near to 9×104and polydispersity index (PDI) of 1.7 was successfully synthesized.

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Selected Physicochemical and Pharmaceutical Properties of Poly-ε-caprolactone and Poly(d,l-lactide-co-ε-caprolactone) Conjugates of Lamivudine Synthesized via Ring-Opening Polymerization

Polymers ◽

10.3390/polym11122124 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2124

Author(s):

Tomasz Urbaniak ◽

Witold Musiał

Keyword(s):

Molecular Weight ◽

Drug Release ◽

Physicochemical Properties ◽

Ring Opening ◽

Ring Opening Polymerization ◽

Submicron Particles ◽

Degree Of Crystallinity ◽

Side Reactions ◽

Burst Release ◽

Reaction Products

The modification of drug fate after administration may be achieved by the covalent coupling of active pharmaceutical ingredients with macromolecules. To prolong or delay the release, slowly degrading polymers such as polyesters may be applied for conjugation. The detachment of a covalently conjugated drug from the polymeric matrix relies mostly on the material degradation profile and barely on the weak interaction between the drug and macromolecules. In the present study, lamivudine was conjugated via ring-opening polymerization with poly-ε-caprolactone and poly(d,l-lactide-co-ε-caprolactone). The influence of the reaction parameters on the course of the polymerization and physicochemical properties of obtained conjugates were investigated. Subsequently, selected reaction products were formulated into submicron particles, and drug release profiles in physiological-like conditions were investigated. The course of the reaction was monitored via gel permeation chromatography. The structure and physicochemical properties of products were evaluated via spectroscopic, calorimetric, and diffractometric methods. The profile of the drug release from particles prepared by the slow evaporation of conjugate solution from o/w emulsion was monitored with high-performance liquid chromatography. Both an elevated reaction temperature and higher catalyst concentration increased the polymerization rate and simultaneously promoted the side reactions, resulting in a broad molecular weight distribution of products in the range from 1.30 to 2.15. The physicochemical properties of conjugates obtained in different conditions varied and had a direct influence on the drug release. The release curve of lamivudine from particles based on low molecular weight conjugates achieved a plateau between 18.9 and 22.2 μg per mg of conjugate within a month. Drug detachment from particles composed of high molecular weight conjugates exhibited a distinct delay period preceded by a drug burst release at a maximal level of 13.3 μg per mg of conjugate. Conjugate chemical composition and the degree of crystallinity were also found to influence the release.

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Synthesis and Characterization of a Novel Biodegradable Polymer with Fluorescence Property

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.21 ◽

2011 ◽

Vol 197-198 ◽

pp. 21-26

Author(s):

Ji Hang Li ◽

Dong Jian Shi ◽

Na Hu ◽

Wei Fu Dong ◽

Jun Feng Li ◽

...

Keyword(s):

Molecular Weight ◽

Ring Opening ◽

Gel Permeation Chromatography ◽

Ring Opening Polymerization ◽

Fluorescence Property ◽

H Nmr ◽

Gel Permeation ◽

Fluorescent Polymer ◽

Poor Solvent

In this paper, a novel biodegradable and fluorescent polymer: fluorescein-polylactide (FL-PLA) was synthesized by FL and lactide in the method of ring-opening polymerization with the catalysis of Sn(Oct)2under 130°C . The structure and molecular weight of FL-PLA were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H-NMR) spectroscopy, and gel permeation chromatography (GPC). The molecular weight of FL-PLA increased from 9.03×103to 21.24×103with decreasing the amount of FL and kept a narrow distribution. The result of differential scanning calorimeter (DSC) showed that Tgincreased from 52 to 72°C with increasing the molecular weight of polymer. Moreover, the average number content of FL in each molecular chain decreased from 0.96 to 0.81 with decrement of the amount of FL. Furthermore, FL-PLA showed the fluorescence property, and the fluorescence intensity could be controlled by the amount of FL. The FL-PLA nanoparticles were prepared by mixing the good and poor solvent, and the diameter was about 3 μm with regular spherical morphology.

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Effects of Frequency and Sonication Time on Ultrasonic Degradation of Natural Rubber Latex

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.747.721 ◽

2013 ◽

Vol 747 ◽

pp. 721-724 ◽

Cited By ~ 4

Author(s):

S. Utara ◽

U. Moonart

Keyword(s):

Molecular Weight ◽

Natural Rubber ◽

Average Molecular Weight ◽

Natural Rubber Latex ◽

Gel Permeation Chromatography ◽

Chain Scission ◽

Polymer Chains ◽

Rubber Latex ◽

Ultrasonic Degradation ◽

The Fourier Transform

Ultrasonic degradation of fresh latex was investigated at frequencies of 20 and 25 kHz, at a constant temperature of 25o C (±1o C) to avoid temperature-related effects. The time-dependent evolution of the molecular weight of the natural rubber latex was determined using gel permeation chromatography, and its structure by means of the fourier transform infrared (FTIR) technique. A 10 minute period of sonication resulted in reduction in the molecular weight of both the 20 and 25 kHz treated samples, the lowest average molecular weight () being obtained in the case of the 25 kHz sample. The of the 25 kHz sample also decreased with increasing latex concentration. However, after 30 minutes, fluctuations had occurred in both samples with respect to the and and also the molecular weight distributions, an effect possibly explained by the competing processes of chain scission and radically-induced cross-linking of the polymer chains. The FTIR results also suggest that the structure of polyisoprene is unaltered by ultrasonic wave treatment at these frequencies.

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A tetranuclear Sn(IV) 4-thiazolecarboxylate complex: synthesis, structure and catalytic behavior in the bulk ring-opening polymerization of glycolide

Zeitschrift für Naturforschung B ◽

10.1515/znb-2015-0211 ◽

2016 ◽

Vol 71 (8) ◽

pp. 843-848 ◽

Cited By ~ 1

Author(s):

Jian Gao ◽

Yu Yuan ◽

Ai-Jun Cui ◽

Feng Tian ◽

Ming-Yang He ◽

...

Keyword(s):

Molecular Weight ◽

Single Crystal ◽

Ring Opening ◽

Glycolic Acid ◽

Average Molecular Weight ◽

Ring Opening Polymerization ◽

Number Average Molecular Weight ◽

X Ray Diffraction ◽

Catalytic Behavior ◽

X Ray

AbstractThe reaction of 4-thiazolecarboxylic acid (Htzc) and dimethyltin(IV) dichloride with NaOH in mixed MeOH-H2O solvent led to the formation of a new Sn(IV) complex (Me2Sn)4(μ3-O)2(tzc)4 (1). Its structure has been characterized by elemental analysis, IR spectroscopy and single crystal and powder X-ray diffraction. Single-crystal X-ray diffraction revealed that complex 1 crystallizes in the monoclinic P21/c space group with Z = 2 and has a tetranuclear structure with crystallographically imposed centrosymmetry. The as-synthesized complex 1 was found to be active toward the bulk solvent-free polymerization of glycolide, producing poly(glycolic acid) with a number-average molecular weight up to 55.5 kDa.

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Lactide synthesis optimization: investigation of the temperature, catalyst and pressure effects

e-Polymers ◽

10.1515/epoly-2014-0055 ◽

2014 ◽

Vol 14 (5) ◽

pp. 353-361 ◽

Cited By ~ 6

Author(s):

Morteza Ehsani ◽

Khosrow Khodabakhshi ◽

Mohammad Asgari

Keyword(s):

Molecular Weight ◽

Ring Opening ◽

Batch Reactor ◽

Analytical Techniques ◽

Gel Permeation Chromatography ◽

Ring Opening Polymerization ◽

Pressure Effects ◽

Synthesis Rate ◽

Antimony Trioxide ◽

Scanning Calorimetry

AbstractThe most applicable method to produce polylactic acid (PLA) is via ring opening polymerization of lactide, which involves three steps: polycondensation of low-molecular-weight PLA (LMW PLA), depolymerization or dimerization of a prepolymer into a cyclic dimer of lactic acid (lactide) and ring opening polymerization of lactide to achieve high-molecular-weight PLA. This work aimed to optimize the reaction conditions of lactide synthesis. Reactions at different temperatures and pressures were carried out in the presence of tin (II) oxide, tin (II) chloride, tin (II) octate, antimony trioxide, sulfuric acid and no catalyst in a semi-batch reactor. Different analytical techniques such as gas chromatography, gel permeation chromatography, differential scanning calorimetry, nuclear magnetic resonance and Fourier transform infrared spectroscopy have been used to evaluate the LMW PLA properties, rate of lactide synthesis and racemization. Results showed that the highest rate of conversion occurred in the presence of tin (II) chloride and octate. Synthesis rate increased with the increase in reaction temperature and the decrease in pressure. Increasing temperature also resulted in higher amounts of optical and chemical impurities in the crude lactide.

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Ring opening polymerization of glycidyl methacrylate by Maghnite-H+ a solid catalyst

Biointerface Research in Applied Chemistry ◽

10.33263/briac15.196202 ◽

2011 ◽

Vol 1 (5) ◽

pp. 196-202 ◽

Cited By ~ 1

Keyword(s):

Molecular Weight ◽

Reaction Time ◽

Ring Opening ◽

Glycidyl Methacrylate ◽

Average Molecular Weight ◽

Weight Ratio ◽

Ring Opening Polymerization ◽

Montmorillonite Clay ◽

Solid Catalyst

In the present work the ring-opening polymerization of glycidyl methacrylate (GMA) using Maghnite-H+, a proton exchanged montmorillonite clay as initiator is reported. The influences of solvent, weight ratio of initiator/monomer and reaction time on the conversion of monomer and on the molecular weight are investigated. Increasing Maghnite-H+ proportion increases (GMA) conversion and decreases the average molecular weight of resulted polymer. A cationic mechanism for the reaction was proposed.

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