Kinetic Investigations on Microwave-Assisted Statistical Terpolymerizations of 2-Oxazoline Monomers

2007 ◽  
Vol 60 (9) ◽  
pp. 656 ◽  
Author(s):  
Richard Hoogenboom ◽  
Frank Wiesbrock ◽  
Mark A. M. Leenen ◽  
Michel van der Loop ◽  
Sjoerd F. G. M. van Nispen ◽  
...  
Keyword(s):  
Polymer Chains ◽  
Size Exclusion ◽  
Order Kinetic ◽  
Microwave Assisted ◽  
Polymer Properties ◽  
Exclusion Chromatography ◽  
Kinetic Plots ◽  
Kinetic Investigations ◽  
Monomer Distribution ◽  
Cationic Ring Opening Polymerization

The microwave-assisted statistical terpolymerization of 2-oxazolines via a living cationic ring-opening polymerization mechanism is discussed. Kinetic investigations on the terpolymerizations of combinations of 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-nonyl-2-oxazoline, and 2-phenyl-2-oxazoline were performed by heating separate polymerization mixtures for different predefined times. The resulting polymer solutions were analyzed by gas chromatography and size exclusion chromatography, demonstrating the living character of the statistical terpolymerizations. In addition, the monomer distribution throughout the polymer chains is discussed based on the linear first order kinetic plots of the separate monomers in the terpolymerizations. The observed differences in monomer distribution are expected to influence the polymer properties, which will be the focus of future investigations.

scholarly journals Homogeneous Distribution of Polymerizable Coumarin Dyes for Active Few Mode POF

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1975
Author(s):  
Florian Jakobs ◽  
Kristoffer Harms ◽  
Jana Kielhorn ◽  
Daniel Zaremba ◽  
Pen Yiao Ang ◽  
...  
Keyword(s):  
Methyl Methacrylate ◽  
Optical Fibers ◽  
High Performance ◽  
Polymer Chains ◽  
Size Exclusion ◽  
Polymerization Process ◽  
Homogeneous Distribution ◽  
Exclusion Chromatography ◽  
Polymer Optical Fibers ◽  
Coumarin Dyes

For most kinds of active polymer optical fibers, a homogeneous distribution of dye molecules over the entire fiber length and cross section is required. In this study, chemical bonding of dyes to poly(methyl methacrylate) (PMMA) by copolymerization is achieved within the polymerization process instead of dissolving the dyes in the monomers. In combination with an improved fabrication mechanism, this leads to homogeneous dye distribution within the preforms. A method for proving the integration of the dyes into the polymer chains has been developed using high-performance liquid chromatography (HPLC) and size exclusion chromatography (SEC). Prestructured core-cladding preforms with dye-doped poly(cylohexyl methacrylate-co-methyl methacrylate)-core have been prepared with the Teflon string technique and were heat-drawn to few mode fibers.

scholarly journals Characterization, Preparation, and Purification of Marine Bioactive Peptides

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Xueqin Wang ◽  
Huahua Yu ◽  
Ronge Xing ◽  
Pengcheng Li
Keyword(s):  
High Performance ◽  
Bioactive Peptides ◽  
Reversed Phase ◽  
Size Exclusion ◽  
Antihypertensive Activity ◽  
Microwave Assisted ◽  
Chemical Hydrolysis ◽  
Assisted Extraction ◽  
Exclusion Chromatography ◽  
Manufacturing Techniques

Marine bioactive peptides, as a source of unique bioactive compounds, are the focus of current research. They exert various biological roles, some of the most crucial of which are antioxidant activity, antimicrobial activity, anticancer activity, antihypertensive activity, anti-inflammatory activity, and so forth, and specific characteristics of the bioactivities are described. This review also describes various manufacturing techniques for marine bioactive peptides using organic synthesis, microwave assisted extraction, chemical hydrolysis, and enzymes hydrolysis. Finally, purification of marine bioactive peptides is described, including gel or size exclusion chromatography, ion-exchange column chromatography, and reversed-phase high-performance liquid chromatography, which are aimed at finding a fast, simple, and effective method to obtain the target peptides.

scholarly journals Synthesis and characterization of amphiphilic graft copolymers of poly(1,3 dioxolane) macromonomers with styrene and methyl methacrylate

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Hayet Bendaikha ◽  
Gérald Clisson ◽  
Abdelouahad Khoukh ◽  
Jeanne François ◽  
Seghier Ould Kada
Keyword(s):  
Methyl Methacrylate ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Molecular Weights ◽  
Molar Ratios ◽  
H Nmr ◽  
Amphiphilic Graft Copolymers ◽  
Exclusion Chromatography ◽  
Cationic Ring Opening Polymerization

AbstractMethacrylate-terminated Poly(1,3 dioxolane) (PDXL) macromonomers were synthesized by cationic ring-opening polymerization in the presence of 2- hydroxypropyl methacrylate (2-HPMA) as transfer agent. Molecular weights, polydispersity index and functionality of the PDXL macromonomers were evaluated by size exclusion chromatography (SEC) and 1H nuclear magnetic resonance spectroscopy (1H-NMR). Copolymerizations of PDXL macromonomers, of different molecular weights, with styrene (St) and methyl methacrylate (MMA) were carried out using various feed molar ratios. The resulting polymers confirmed the grafting of PDXL with PS and PMMA by SEC and 1H-NMR Monomer reactivity ratios between the macromonomers and the comonomers were estimated from the copolymerization results. Macromonomer reactivity depends on the comonomer considered. Glass transition temperatures of the copolymers were found to decrease with an increase in the amount of PDXL in the copolymers. The values of Tg depend on the composition and the size of the PDXL grafts.

Copolymers Obtained by ε-Caprolactam and Methyl Methacrylate Polymerization in the Presence of Polyimides

2009 ◽  
Vol 21 (5) ◽  
pp. 579-595 ◽  
Author(s):  
Yakov S. Vygodskii ◽  
Tat'yana V. Volkova ◽  
Tat'yana L. Batalova ◽  
Olesya N. Zabegaeva ◽  
Elena M. Belavtseva ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Methyl Methacrylate ◽  
Compression Modulus ◽  
Size Exclusion ◽  
Mechanical And Tribological Properties ◽  
Copolymer Films ◽  
Polymer Properties ◽  
Methyl Methacrylate Polymerization ◽  
Exclusion Chromatography ◽  
Kinetics Of

New copolymers have been synthesized by anionic or radical photopolymerization of ε-caprolactam or methyl methacrylate (MMA) in the presence of dissolved polyimides bearing hexafluoroisopropylidene, fluorene or other groups. Using diimides as models it was shown that the kinetics of anionic polymerization of ε-caprolactam depends on the nature of spacer between the imide cycles. The mechanical and tribological properties of copolymers, their water absorbance and the microstructure of copolymer films were studied. It was found that upon the selection of polyimide activator it was possible to gain the desirable control over the polymer properties, namely, the gel fraction content, phase composition, compression modulus, notched Izod impact strength, friction coefficient and temperature of frictional contact. The kinetics of radical polymerization of MMA in the presence of polyimide and model diimide has been studied by differential scanning photocalorimetry and infrared spectroscopy. From the results of the reaction kinetics and the study of polymer structures by Fourier transform infrared spectroscopy, nuclear magnetic resonance, size-exclusion chromatography and thermogravimetric analysis it has been established that radical photopolymerization of MMA in the presence of polyimide leads to the formation of copolymers owing to chain transfer reactions and/or chain termination by the relevant condensation polymer. It has been established that the imide cycles play a significant role in the formation of both copolymers with ε-caprolactam and MMA, respectively.

scholarly journals A Novel Strategy for the Synthesis of Amphiphilic and Thermoresponsive Poly(N-isopropylacrylamide)-b-Polystyrene Block Copolymers via ATRP

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1484 ◽  
Author(s):  
Magdalena Fedorczyk ◽  
Anna Krzywicka ◽  
Piotr Cieciórski ◽  
Jan Romański ◽  
Elżbieta Megiel
Keyword(s):  
Block Copolymers ◽  
Polymer Chains ◽  
Size Exclusion ◽  
Synthetic Approach ◽  
Scanning Calorimetry ◽  
Styrene Polymerization ◽  
Exclusion Chromatography ◽  
Arget Atrp ◽  
Novel Strategy ◽  
Two Stages

A new synthetic approach is presented for the preparation of Poly(N-isopropylacrylamide-block-styrene) PNIPAM-b-PS via an Atom Transfer Radical Polymerization (ATRP) technique. The proposed method is based on application of 2-chloro-N-(2-hydroxyethyl)propanamide (NCPAE) as a bifunctional initiator, which enables ATRP of two monomers, differing in activity and polarity, into two stages. The synthesized copolymer molecules contain two well-defined polymer chains connected by a linker, which is a derivative of the proposed initiator. Using NCPAE led to PNIPAMs with well-planned molecular weight, low polydispersities (PDI=1.1÷1.3) and hydroxyl functionality. Activation of such blocks for initiation of styrene polymerization was performed using α-bromoisobutyryl bromide. After such a modification, the synthesized homopolymers acted as macroinitiators in ARGET ATRP and a well-defined polystyrene block, as the next one in the polymer chain was successfully formed. Both of the synthesized macromolecules, PNIPAM and PNIPAM-b-PS, exhibit a thermoresponsive behavior with explicit lower critical solution temperatures (LCST) in their aqueous solutions. The synthesized homopolymers and subsequently derived block copolymers were characterized using Size-Exclusion Chromatography, Differential Scanning Calorimetry, Dynamic Light Scattering, and NMR spectroscopy.

Mapping the Compaction of Discrete Polymer Chains by Size Exclusion Chromatography Coupled to High-Resolution Mass Spectrometry

2019 ◽  
Vol 52 (6) ◽  
pp. 2597-2606 ◽  
Author(s):  
Tobias Nitsche ◽  
Jan Steinkoenig ◽  
Kevin De Bruycker ◽  
Fabian R. Bloesser ◽  
Stephen J. Blanksby ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Size Exclusion Chromatography ◽  
High Resolution Mass Spectrometry ◽  
Polymer Chains ◽  
Size Exclusion ◽  
High Resolution Mass ◽  
Exclusion Chromatography ◽  
Resolution Mass

scholarly journals Efficient Synthesis of Single-Chain Polymer NanoparticlesviaAmide Formation

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ana Sanchez-Sanchez ◽  
José A. Pomposo
Keyword(s):  
Polymer Chains ◽  
Size Exclusion ◽  
Proton Nuclear Magnetic Resonance ◽  
Efficient Synthesis ◽  
Single Chain ◽  
Chain Polymer ◽  
H Nmr ◽  
Exclusion Chromatography ◽  
Methylene Groups

Single-chain technology (SCT) allows the transformation of individual polymer chains to folded/collapsed unimolecular soft nanoparticles. In this work we contribute to the enlargement of the SCT toolbox by demonstrating the efficient synthesis of single-chain polymer nanoparticles (SCNPs)viaintrachain amide formation. In particular, we exploit cross-linking between active methylene groups and isocyanate moieties as powerful “click” chemistry driving force for SCNP construction. By employing poly(methyl methacrylate)- (PMMA-) based copolymers bearingβ-ketoester units distributed randomly along the copolymer chains and bifunctional isocyanate cross-linkers, SCNPs were successfully synthesized at r.t. under appropriate reaction conditions. Characterization of the resulting SCNPs was carried out by means of a combination of techniques including size exclusion chromatography (SEC), infrared (IR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, dynamic light scattering (DLS), and elemental analysis (EA).

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