scholarly journals A Novel Synthesis of Poly(Ester-Alt-Selenide)s by Ring-Opening Copolymerization of γ-Selenobutyrolactone and Epoxy Monomer

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1203 ◽  
Author(s):  
Ya’nan Wang ◽  
Xiaofang Lin ◽  
Zhengbiao Zhang ◽  
Jian Zhu ◽  
Xiangqiang Pan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Effective Means ◽  
Linear Structure ◽  
Size Exclusion ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Epoxy Monomer ◽  
Polymerization System ◽  
Exclusion Chromatography

Ring-opening copolymerization (ROCOP) is an effective means to prepare functionalized polyester. In this work, a type of selenide-containing polyesters with controllable structure, molecular weight, and molecular weight distribution was successfully prepared by ROCOP of γ-selenobutyrolactone and epoxy compounds. The influence of the catalyst, solvent, and reaction temperature on the reaction efficiency was examined. Then, kinetic study was investigated under an optimized condition. The structure of the copolymers was carefully characterized by nuclear magnetic resonance (NMR), 1H NMR, 13C NMR, and 77Se NMR, Matrix-assisted laser-desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and size exclusion chromatography (SEC). The resulting polymers showed a linear structure with a sequence regulated backbone repeating unit of ester-selenide. On this basis, some typical epoxides were investigated to verify the scope of the polymerization system. Due to the “living”/controlled characteristics of this ROCOP, multiblock, amphiphilic, and stereotactic copolymers could be prepared with a pre-designed structure. As expected, the selenide-containing amphiphilic copolymer could self-assemble to micelles and showed an oxidative response.

Consecutive determination of softwood kraft lignin structure and molar mass from NMR measurements

Holzforschung ◽  
2017 ◽  
Vol 71 (7-8) ◽  
pp. 563-570 ◽  
Author(s):  
Jerk Rönnols ◽  
Anna Jacobs ◽  
Fredrik Aldaeus
Keyword(s):  
Molar Mass ◽  
Industrial Applications ◽  
Size Exclusion ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Exclusion Chromatography ◽  
Pfg Nmr ◽  
Softwood Kraft Lignin ◽  
Good Agreement

Abstract The general molecular properties and in particular, the molar mass of lignin are of central importance for industrial applications, as these data govern important thermal and mechanical characteristics. The focus of the present paper is pulsed field gradient-nuclear magnetic resonance (PFG-NMR), which is suitable for determination of lignins’ weight-average molar mass, based on diffusion constants. The method is calibrated by lignin fractions characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). It could be demonstrated on a set of softwood kraft lignins that the PFG-NMR approach gives results in very good agreement with those obtained using conventional size exclusion chromatography (SEC).

Analysis of carbohydrates in Fusarium verticillioides using size-exclusion HPLC – DRI and direct analysis in real time ionization – time-of-flight – mass spectrometry (DART-MS)

2016 ◽  
Vol 8 (3) ◽  
pp. 673-681 ◽  
Author(s):  
Ethan S. Roberts ◽  
Beth A. Boudreau ◽  
Daren W. Brown ◽  
Kristi L. McQuade ◽  
Edward E. Remsen
Keyword(s):  
Mass Spectrometry ◽  
Real Time ◽  
Fusarium Verticillioides ◽  
Time Of Flight ◽  
Direct Analysis ◽  
Size Exclusion ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Exclusion Chromatography ◽  
Size Exclusion Hplc

Direct analysis in real time – time of flight – mass spectrometry (DART-TOF-MS) and size-exclusion chromatography (SEC) are used to analyze carbohydrates inF. verticillioides, such as trehalose.

Star-shaped poly(2-ethyl-2-oxazoline) featuring a porphyrin core: synthesis and metal complexation

e-Polymers ◽  
2015 ◽  
Vol 15 (4) ◽  
pp. 227-235 ◽  
Author(s):  
Tobias Rudolph ◽  
Sarah Crotty ◽  
Ulrich S. Schubert ◽  
Felix H. Schacher
Keyword(s):  
Metal Ion ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Visible Spectroscopy ◽  
Central Cavity ◽  
One Pot ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Exclusion Chromatography ◽  
Porphyrin Core

AbstractWe demonstrate the synthesis of star-shaped poly(2-ethyl-2-oxazoline) featuring a porphyrin core starting from alkyne-functionalized porphyrin ([TPP-TB]4) and azide-functionalized poly(2-ethyl-2-oxazoline) (PEtOx-N3) via copper-catalyzed azide-alkyne cycloaddition (CuAAC). The porphyrin core was further utilized for the complexation of either copper or iron within the central cavity. The obtained materials were investigated using a combination of nuclear magnetic resonance spectroscopy, fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, size-exclusion chromatography, and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. In the case of copper, the inclusion of the metal ion was achieved in a one-pot reaction during the CuAAC reaction for attaching the PEtOx-N3 arms.

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