Synthesis and Micellar Properties of Star-Shaped Poly(ε-Caprolactone)-Dextran Amphiphilic Block Copolymer

2011 ◽  
Vol 239-242 ◽  
pp. 2711-2716
Author(s):  
Xue Qing Liu ◽  
Ji Yan Liu
Keyword(s):  
Ring Opening ◽  
Ph Value ◽  
Star Polymer ◽  
Element Analysis ◽  
H Nmr ◽  
Micellar Properties ◽  
The Core ◽  
Micelle Size ◽  
Form Star ◽  
End Group

6-arm star-shaped Poly (ε-caprolactone)-dextran (sPCL-dextran) was synthesized and characterized. The core of the star polymer is dipentaerythritol, the inner block in the arm is hydrophobic poly (ε-caprolactone) (PCL), and the outer block in the arm is hydrophilic dextran. The synthesis involves three steps: (1) The ring-opening polymerization of ε-caprolactone (CL) initiated by dipentaerythritol produces 6-arm star-shaped PCL (sPCL-OH). (2) The sPCL-OH reacts with acryloyl chloride to get star-shaped PCL with acrylate end group (sPCL-CH=CH2). (3) The amino ended dextran (dextran-NH2) is then attached to sPCL-CH=CH2 terminus by Micheal addition to form star-shaped sPCL-dextran. The architecture of products was characterized with 1H NMR, GPC and element analysis. Micellization of sPCL-dextran in aqueous solutions was investigated by DLS. The results showed that the micelle size (Rh) and size distribution are related to the concentration of the sPCL-dextran. Salt, pH value and temperature have no obvious influence on the Rh.

Synthesis of Poly(2-methyl-2-oxazoline) Star Polymers with a β-Cyclodextrin Core

2012 ◽  
Vol 65 (8) ◽  
pp. 1145 ◽  
Author(s):  
Guillaume Pereira ◽  
Cécile Huin ◽  
Simona Morariu ◽  
Véronique Bennevault-Celton ◽  
Philippe Guégan
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Allyl Bromide ◽  
Star Polymers ◽  
Star Polymer ◽  
Kinetic Measurements ◽  
Hydrodynamic Volume ◽  
The Core ◽  
Initiation And Propagation ◽  
Propagation Kinetic

Synthesis of star polymers with a β-cyclodextrin (CD) core was undertaken using the arm-first, then the core-first strategy. Cationic ring opening polymerisation (CROP) of 2-methyl-2-oxazoline (MeOx) was first initiated by allyl bromide, and then quenched with heptakis(6-deoxy-6-amino)β-CD in order to get a 7-arm star polymer. Then heptakis(6-deoxy-6-iodo-2,3-di-O-acetyl)β-CD was synthesised in order to get an initiator for the CROP of MeOx. Initiation and propagation kinetic measurements were undertaken and the ratio kp/ki was found to be too high to provide a controlled polymerisation. Using iodine as co-initiator allowed a decrease of the kp/ki ratio that gave better control of the polymerisation. DOSY NMR and viscosity characterisations were undertaken, and both techniques lead to the demonstration of a lower hydrodynamic volume of the star polymers versus the linear counterparts, for compounds of the same molecular weight.

scholarly journals Ring opening metathesis polymerization of cyclopentene using a ruthenium catalyst confined by a branched polymer architecture

2016 ◽  
Vol 7 (17) ◽  
pp. 2923-2928 ◽  
Author(s):  
Clément Mugemana ◽  
Konstantin V. Bukhryakov ◽  
Olivier Bertrand ◽  
Khanh B. Vu ◽  
Jean-François Gohy ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ruthenium Catalyst ◽  
Star Polymer ◽  
Ring Opening Metathesis Polymerization ◽  
Polymer Architecture ◽  
Branched Polymer ◽  
Metathesis Polymerization ◽  
The Core ◽  
Metathesis Catalyst

A Grubbs-type Ru alkene metathesis catalyst has been covalently anchored in the core of a globular star polymer. The spatially-confined catalyst is capable of efficient ring-opening metathesis polymerization of cyclopentene, a low-strain monomer.

The Preparation and Characterization of ABC-Shaped Star Copolymer of MPEG-PCL-PBLG

2013 ◽  
Vol 750-752 ◽  
pp. 1358-1362
Author(s):  
Dian Guang Geng ◽  
Yong Ming Chuan ◽  
Li Li Li ◽  
Ming Long Yuan
Keyword(s):  
Ring Opening ◽  
Graft Polymerization ◽  
Ring Opening Polymerization ◽  
Poly Ethylene Glycol ◽  
H Nmr ◽  
The Core ◽  
Poly Ethylene ◽  
Copolymer Poly ◽  
Star Copolymer

A novel biodegradable ABC-shaped star copolymer, poly (ethylene glycol)(PEG)-b-poly (ε-caprolactone)(PCL)-poly-c-poly (ɤ-benzyl-L-glutamic acid)(PBLG)(MPEG-PCL-PBLG), was synthesized by the graft polymerization of MPEG-NH2with the core of Boc-LYSZ-COOH and the twice ring-opening polymerization (ROP) of ε-caprolactone (CL) and N-carboxyanhydride of ɤ-benzyl-L-glutamate (BLGNCA) with centrally amino-functionalized lysine as a initiator. The ABC-shaped star copolymer and its precursors were characterized by1H NMR, GPC, and DSC-TG measurements.

Six-Sided Heptaporphyrin Array: Towards a Nano-Sized Cube

2004 ◽  
Vol 69 (5) ◽  
pp. 996-1008 ◽  
Author(s):  
Steven J. Langford ◽  
Clint P. Woodward
Keyword(s):  
Single Step ◽  
One Pot ◽  
H Nmr ◽  
The Core ◽  
Nmr Techniques ◽  
Axial Vertex

A strategy in preparing a family of hexameric porphyrin cubes based on the interplay of Sn(IV)-O and Ru(II)-N interactions is described. In this first iteration, we have prepared the heptamer [SnIV(TPyP)·(4)2][Ru(CO)(TPP)]6 (4 = (E)-(3-(4-pyridyl)acrylate)) constituting a 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) core and 5,10,15,20-tetraphenylporphyrin (TPP) faces and compared its formation by stepwise and "one-pot" strategies where up to nine components are assembled in a single step in a regiospecific manner. In one example, the heptamer is formed around the template [SnIV(TPyP)·(4)2] bearing pyridine groups in which the nitrogens radiate octahedrally along each vertex. The ability to modulate the axial vertex through choice of pyridine is also demonstrated. 1H NMR measurements on [SnIV(TPyP)·(4)2][Ru(CO)(TPP)]6 indicate that the protons on the core template are extremely shielded as a result of the anisotropy of the peripheral porphyrin units. Various NMR techniques, including NOESY experiments, have been used to characterise the heptamer in solution.

scholarly journals Synthesis and characterization of different soybean oil-based polyols with fatty alcohol and aromatic alcohol

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 491-499
Author(s):  
Fukai Yang ◽  
Hao Yu ◽  
Yuyuan Deng ◽  
Xinyu Xu
Keyword(s):  
Molecular Weight ◽  
Soybean Oil ◽  
Retention Time ◽  
Ring Opening ◽  
Isoamyl Alcohol ◽  
Synthesis And Characterization ◽  
Intermolecular Force ◽  
H Nmr ◽  
Epoxy Groups

Abstract In this article, five kinds of soybean oil-based polyols (polyol-E, polyol-P, polyol-I, polyol-B, and polyol-M) were prepared by ring-opening the epoxy groups in epoxidized soybean oil (ESO) with ethyl alcohol, 1-pentanol, isoamyl alcohol, p-tert-butylphenol, and 4-methoxyphenol in the presence of tetrafluoroboric acid as the catalyst. The SOPs were characterized by FTIR, 1H NMR, GPC, viscosity, and hydroxyl numbers. Compared with ESO, the retention time of SOPs is shortened, indicating that the molecular weight of SOPs is increased. The structure of different monomers can significantly affect the hydroxyl numbers of SOPs. Due to the large steric hindrance of isoamyl alcohol, p-hydroxyanisole, and p-tert-butylphenol, SOPs prepared by these three monomers often undergo further dehydration to ether reactions, which consumes the hydroxyl of polyols, thus forming dimers and multimers; therefore, the hydroxyl numbers are much lower than polyol-E and polyol-P. The viscosity of polyol-E and polyol-P is much lower than that of polyol-I, polyol-B, and polyol-M. A longer distance between the molecules and the smaller intermolecular force makes the SOPs dehydrate to ether again. This generates dimer or polymers and makes the viscosity of these SOPs larger, and the molecular weight greatly increases.

scholarly journals Characteristic Analysis and Structural Design of Hollow-Core Photonic Crystal Fibers with Band Gap Cladding Structures

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 284
Author(s):  
Bowei Wan ◽  
Lianqing Zhu ◽  
Xin Ma ◽  
Tianshu Li ◽  
Jian Zhang
Keyword(s):  
Photonic Crystal ◽  
Band Gap ◽  
Photonic Crystal Fibers ◽  
Relative Sensitivity ◽  
Confinement Loss ◽  
Hollow Core ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
The Core ◽  
Crystal Fibers

Due to their flexible structure and excellent optical characteristics hollow-core photonic crystal fibers (HC-PCFs) are used in many fields, such as active optical devices, communications, and optical fiber sensing. In this paper, to analyze the characteristics of HC-PCFs, we carried out finite element analysis and analyzed the design for the band gap cladding structure of HC-PCFs. First, the characteristics of HC19-1550 and HC-1550-02 in the C-band were simulated. Subsequently, the structural optimization of the seven-cell HC-1550-02 and variations in characteristics of the optimized HC-1550-02 in the wavelength range 1250–1850 nm were investigated. The simulation results revealed that the optimal number of cladding layers is eight, the optimal core radius is 1.8 times the spacing of adjacent air holes, and the optimal-relative thickness of the core quartz-ring is 2.0. In addition, the low confinement loss bandwidth of the optimized structure is 225 nm. Under the transmission bandwidth of the optimized structure, the core optical power is above 98%, the confinement loss is below 9.0 × 10−3 dB/m, the variation range of the effective mode field area does not exceed 10 μm2, and the relative sensitivity is above 0.9570. The designed sensor exhibits an ultra-high relative sensitivity and almost zero confinement loss, making it highly suitable for high-sensitivity gas or liquid sensing.

Synthesis of binary-patterned brushes by combining atom transfer radical polymerization and ring-opening polymerization

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Aurore Olivier ◽  
Franck Meyer ◽  
Jean-Marie Raquez ◽  
Philippe Dubois
Keyword(s):  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Ring Opening ◽  
Microcontact Printing ◽  
Gold Surface ◽  
Ring Opening Polymerization ◽  
Careful Study ◽  
Atom Transfer ◽  
Final Thickness ◽  
End Group

Abstract This paper report the synthesis of binary-patterned brushes, combining two distinctive surface initiated-polymerizations (SIP) on the basis of different propagating species: the SI Ring Opening Polymerization (ROP) of L-Lactide (LLA) and SI atom transfer radical polymerization (ATRP) of N,N’-dimethylaminoethyl methacrylate (DMAEMA) on gold surface. First of all, a careful study of surfaceinitiated ROP of L-Lactide from hydroxyl end-group of thiol monolayer on gold surface as catalyzed by metal-free catalyst was carried out. The PLLA brushes synthesis was evaluated using two types of thiol monolayer and revealed the influence of ROP initiator chain length on the final thickness of the PLLA film. Combining the soft lithographic technique, microcontact printing, and the liquid phase deposition, the deposition onto specific micro-domains of both initiators was performed. The growth of PDMAEMA brushes and PLLA brushes was conducted by successive ATRP and ROP.

scholarly journals Synthesis and Characterization of Polyphosphazenes Modified with Hydroxyethyl Methacrylate and Lactic Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Evelyn Carolina Martínez Ceballos ◽  
Ricardo Vera Graziano ◽  
Gonzalo Martínez Barrera ◽  
Oscar Olea Mejía
Keyword(s):  
Lactic Acid ◽  
Ring Opening ◽  
Room Temperature ◽  
Block Structure ◽  
Ring Opening Polymerization ◽  
Synthesis And Characterization ◽  
Poly Lactic Acid ◽  
Hydroxyethyl Methacrylate ◽  
H Nmr

Poly(dichlorophosphazene) was prepared by melt ring-opening polymerization of the hexachlorocyclotriphosphazene. Poly[bis(2-hydroxyethyl-methacrylate)-phosphazene] and poly[(2-hydroxyethyl-methacrylate)-graft-poly(lactic-acid)-phosphazene] were obtained by nucleophilic condensation reactions at different concentrations of the substituents. The properties of the synthesized copolymers were assessed by FTIR,1H-NMR and31P-NMR, thermal analysis (DSC-TGA), and electron microscopy (SEM). The copolymers have a block structure and show twoTg's below room temperature. They are stable up to a temperature of 100°C. The type of the substituents attached to the PZ backbone determines the morphology of the polymers.

scholarly journals Kinetics of radical telomerization of acrylic acid in the presence of 1-octadecanethiol

2018 ◽  
Vol 90 (11) ◽  
pp. 1743-1754 ◽  
Author(s):  
Yaroslav O. Mezhuev ◽  
Oksana Y. Sizova ◽  
Yuri V. Korshak ◽  
Anna L. Luss ◽  
Ivan V. Plyushchii ◽  
...  
Keyword(s):  
Critical Micelle Concentration ◽  
Acrylic Acid ◽  
Monomer Concentration ◽  
Atom Economy ◽  
Exponential Factor ◽  
H Nmr ◽  
Radical Telomerization ◽  
Kinetics Of ◽  
End Group ◽  
C Nmr

AbstractThe oligomer of acrylic acid with a thiooctadecyl end-group was obtained by using octadecyl mercaptan as the chain-transfer agent. The resulting oligomer was characterized by 1H NMR and 13C NMR spectroscopy and critical micelle concentration was determined in aqueous solution. The order with respect to the initiator concentration was 0.5 and 1.6 with respect to the monomer concentration. The abnormal reaction order with respect to the monomer concentration was explained by participation in the chain propagation of unassociated and associated forms of acrylic acid, which were stabilized by formation of hydrogen bonds. The kinetic parameters of telomerization were determined. Telomerization with acrylic acid in the non-associated form had lower activation energy and lower pre-exponential factor than in the case of associated forms. The synthesis of the acrylic acid oligomer with a thiooctadecyl end-group having a low critical micelle concentration in water was carried out in one stage and corresponds to the concept of atom economy.

The Finite Element Analysis on the Local Compression of the Concrete Filled Steel Tubular Column-Beam Joint

2011 ◽  
Vol 368-373 ◽  
pp. 489-494 ◽  
Author(s):  
Xu Lin Tang ◽  
Jian Cai ◽  
Qing Jun Chen ◽  
An He ◽  
Chun Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compressive Stress ◽  
Element Analysis ◽  
Joint Zone ◽  
The Core ◽  
Principal Compressive Stress ◽  
The Finite Element Analysis ◽  
Side Face ◽  
Core Concrete

In order to study the mechanical behavior of the joint between concrete filled steel tubular column and beam with discontinuous column tube at the joint zone under axial pressure, the finite element analysis software ANSYS is adopted for parametric analysis and the analysis results are compared with experimental ones. The principal compressive stress is mainly transmitted by the inside area of the joint which is subjected to local compression if it is low, but extends to more outside areas of the joint if it is high. The radial compressive stress, which is the confined stress of the ring beam to the core concrete of the joint, keeps the same as that the width of the ring beam equal to the diameter of the core area of the joint. The vertical strain on the edge of the joint, which would lead to horizontal annular cracks in the side face of the ring beam, changes from tension in the whole height to tension only in the top part and compression in the lower part of the joint, which is consistent with the experimental phenomenon.

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