scholarly journals Lastingly Colored Polylactide Synthesized by Dye-Initiated Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1980
Author(s):  
Dawid Jędrzkiewicz ◽  
Sebastian Kowalczyk ◽  
Andrzej Plichta ◽  
Jolanta Ejfler
Keyword(s):  
Molar Mass ◽  
Gel Permeation Chromatography ◽  
Polymer Fibers ◽  
Mass Distributions ◽  
Synthesis Strategy ◽  
Structure Of Metal ◽  
Distribution Index ◽  
Array Detection ◽  
Zinc Coordination ◽  
Very High

An efficient synthesis strategy of a well-defined polylactide–dye conjugate in a controlled fashion is presented. The introduction of coloring species as end groups of polylactide (PLA) has been performed by using new homoleptic aminophenolate magnesium or zinc coordination compounds. The molecular structure of metal complexes has been determined in solution by NMR spectroscopy, and in the solid state by X-ray analysis. Lastingly colored polymers were obtained with 2-[4-(Nitrophenylazo)-N-ethylphenylamino]ethanol (Disperse Red 1) and 2-[4-(2-Chloro-4-nitrophenylazo)-N-ethylphenylamino]ethanol (Disperse Red 13) at very high lactide conversions, based on MALDI-ToF measurement, and the macromolecules were nearly fully chain end dye-functionalized. Based on 1H NMR, the DPn of conjugates was in the range of 10–300, which was consistent with the reaction setup. Various methods of gel-permeation chromatography (GPC) analysis were applied, and they demonstrated that the number-average molar mass (Mn) values (polystyrene (PS) standards) were a bit higher than calculated, the molar mass distribution index (ƉM) values were moderate to high, the TDA (triple detection array) system was inappropriate for analysis, measurements with PDA (photo diode array) detection at 470 nm gave nearly the same molar mass distributions such as the refractometer, and the relative absorbance of conjugates at 470 nm increased linearly versus (DPn)−1. The presented approach connects the gap between the current strategy of obtaining colored polymer fibers and the design of tailor-made initiators with eco polyesters designed for the targeted applications.

scholarly journals Effect of PEEK degradation on commingled fabrics consolidation

2021 ◽  
Author(s):  
Lisa Feuillerat ◽  
Olivier De Almeida ◽  
Jean-Charles Fontanier ◽  
Fabrice Schmidt
Keyword(s):  
Melt Spinning ◽  
Molar Mass ◽  
Degradation Kinetics ◽  
Gel Permeation Chromatography ◽  
Raw Material ◽  
High Porosity ◽  
Absorption Bands ◽  
Mass Distributions ◽  
Key Factor ◽  
Lower Molar

The effects of PEEK degradation on consolidation of commingled semi-finished products have been investigated. Two commingled semi-finished products provided by two different suppliers have been studied and compared to a powdered fabric based on the same PEEK grade. Both were manufactured from aligned AS4 carbon and PEEK yarns but the first product referred as the NCF1 has a lower commingling level than the second one identified as the NCF2. Contrary to what could be expected, under the same processing conditions, consolidation of the NCF1 and the NCF2 systematically results in a high porosity content, above 10%. Fourier Transform Infrared spectrophotometry (FTIR) in ATR mode and Gel Permeation Chromatography (GPC) have shown small molecular structure modifications of PEEK yarns compared to the raw material, such as a shift of molar mass distributions towards lower molar mass and the appearance of C-H absorption bands attributed to non-aromatic alkanes. These modifications have been attributed to sizing of PEEK filament. Calorimetric (DSC) and rheological analyses have demonstrated that the presence of sizing in the semi-finished products have huge consequences on the degradation kinetics. The crystallization temperature decreases and the viscosity increases significantly. This acceleration of the degradation kinetics is the reason of the poor consolidation behavior during composite manufacturing. The conditions of melt spinning extrusion under which the neat PEEK is transformed into filament are therefore a key factor of PEEK degradation.

QELSS diffusion data for moderately broad molar mass distribution polymer samples compared with data from classical gradient techniques

1989 ◽  
Vol 54 (7) ◽  
pp. 1821-1829
Author(s):  
Bedřich Porsch ◽  
Simon King ◽  
Lars-Olof Sundelöf
Keyword(s):  
Diffusion Coefficient ◽  
Mass Distribution ◽  
Molar Mass ◽  
Molar Mass Distribution ◽  
Diffusion Data ◽  
Mass Distributions ◽  
Classical Diffusion ◽  
Polydisperse Polymer

The differences between the QELSS and classical diffusion coefficient of a polydisperse polymer resulting from distinct definitions of experimentally accessible average values are calculated for two assumed specific forms of molar mass distributions. Predicted deviations are compared with the experiment using NBS 706 standard polystyrene. QELSS Dz of this sample relates within 2-4% to the classical diffusion coefficient, if the Schulz-Zimm molar mass distribution is assumed to be valid. In general, differences between the height-area and QELSS diffusion coefficient of about 20% may be found for Mw/Mn ~ 2, and this value may increase above 35%, if strongly tailing molar mass distribution pertains to the sample.

scholarly journals Molar mass determination of lignins and characterization of their polymeric structures by multi-detector gel permeation chromatography

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Evamaria C. Gaugler ◽  
Wolfgang Radke ◽  
Andrew P. Vogt ◽  
Dawn A. Smith
Keyword(s):  
Molar Mass ◽  
Lithium Bromide ◽  
Gel Permeation Chromatography ◽  
Mass Determination ◽  
Organosolv Lignin ◽  
Gel Permeation ◽  
Softwood Kraft Lignin ◽  
Polymeric Structures

AbstractMolar masses, Mark-Houwink-Sakurada (MHS) exponents, and refractive index increments (dn/dc) for three lignins were determined without derivatization by multi-detector gel permeation chromatography (GPC) in dimethylformamide (DMF) with 0.05 M lithium bromide (LiBr). The lack of effectiveness of fluorescence filters on molar mass determination by GPC-multi-angle laser light scattering (MALS) was confirmed for softwood kraft lignin (Indulin AT) and revealed for mixed hardwood organosolv lignin (Alcell) as well as soda straw/grass lignin (Protobind 1000). GPC with viscometry detection confirmed that these lignins were present as compact molecules. The MHS exponent α for Indulin AT and Alcell was in the order of 0.1. Additionally, the intrinsic viscosity of Protobind 1000 for a given molar mass was much lower than that of either Alcell or Indulin AT. This is the first report of dn/dc values for these three lignins in DMF with 0.05 M LiBr.

scholarly journals Synthesis and Characterization of a Multifunctional Conjugated Polymer

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Emerson C. G. Campos ◽  
Cristiano Zanlorenzi ◽  
Bruno F. Nowacki ◽  
Gabriela M. Miranda ◽  
Denis A. Turchetti ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Molar Mass ◽  
Photophysical Properties ◽  
Gel Permeation Chromatography ◽  
Thermal Characterization ◽  
Polymer Structure ◽  
Synthesis And Characterization ◽  
Metallic Ions ◽  
Scanning Calorimetry

This work reports the synthesis and characterization of a conjugated polymer based on fluorene and terpyridine, namely, poly[(9,9-bis(3-((S)-2-methylbutylpropanoate))fluorene-alt-6,6′-(2,2′:6′,2′′-terpyridin-6-yl)] (LaPPS71). The structure was characterized by 1H and 13C nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopy. The molar mass was measured by gel permeation chromatography (GPC). As thermal characterization, the glass transition temperature (Tg) was measured by differential scanning calorimetry (DSC). The polymer structure contains two sites capable of complexation with metallic ions, affording the possibility of obtainment of independent or electronically coupled properties, depending on the complexation site. The photophysical properties were fully explored in solution and solid state, presenting ideal results for the preparation of various metallopolymers, in addition to potential application as a metamaterial, due to the presence of the chiral center in the side chains of the polymer.

scholarly journals Degradable Polymer Stars Based on Tannic Acid Cores by ATRP

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 752 ◽  
Author(s):  
Julia Cuthbert ◽  
Saigopalakrishna S. Yerneni ◽  
Mingkang Sun ◽  
Travis Fu ◽  
Krzysztof Matyjaszewski
Keyword(s):  
Tannic Acid ◽  
Molar Mass ◽  
Gel Permeation Chromatography ◽  
Degradable Polymers ◽  
Degradable Polymer ◽  
Cytotoxicity Assays ◽  
Before And After ◽  
Phenolic Esters ◽  
Ft Ir ◽  
Waste Accumulation

Degradable polymers are crucial in order to reduce plastic environmental pollution and waste accumulation. In this paper, a natural product, tannic acid was modified to be used as a polymer star core. The tannic acid was modified with atom transfer radical polymerization (ATRP) initiators and characterized by 1H NMR, FT-IR, and XPS. Twenty-five arm polymer stars were prepared by photoinduced ATRP of poly(methyl methacrylate) (PMMA) or poly(oligo(ethylene oxide) methacrylate) (molar mass Mw = 300 g/mol) (P(OEO300MA)). The polymer stars were degraded by cleaving the polymer star arms attached to the core by phenolic esters under mild basic conditions. The stars were analyzed before and after degradation by gel permeation chromatography (GPC). Cytotoxicity assays were performed on the P(OEO300MA) stars and corresponding degraded polymers, and were found to be nontoxic at the concentrations tested.

Dinuclear Nickel(II) and Palladium(II) Complexes in Combination with Different Co-Catalysts as Highly Active Catalysts for the Vinyl/Addition Polymerization of Norbornene

2003 ◽  
Vol 58 (12) ◽  
pp. 1152-1164 ◽  
Author(s):  
Vasile Lozana ◽  
Paul-Gerhard Lassahn ◽  
Cungen Zhang ◽  
Biao Wu ◽  
Christoph Janiak ◽  
...  
Keyword(s):  
Molar Mass ◽  
Active Species ◽  
Schiff Base Ligands ◽  
Coordination Polymerization ◽  
Polymer Characterization ◽  
Mass Distributions ◽  
Molar Ratios ◽  
Co Catalysts ◽  
Highly Active ◽  
Addition Polymerization

Dinuclear nickel(II) and palladium(II) complexes with Schiff-base ligands (derived form salicylaldehyde condensed with 2-amino-1-alcohols or from 2-hydroxy-5-methylisophthaldialdehyde and pyridine-2-carboxaldehyde condensed with semicarbazide, thiosemicarbazide, carbonodihydrazide, or thiocarbonodihydrazide) can be activated with the co-catalysts methylalumoxane (MAO) or tris(pentafluorophenyl)borane/triethylaluminium, B(C6F5)3/AlEt3 for the vinyl/addition polymerization of norbornene to reach activities of up to 2.4 · 107 gpolymer/mol(metal)·h (molar ratios metal:AlMAO = 1:100, metal:borane:AlEt3 = 1:9:10). Polymer characterization by GPC gave molar mass distributions of Mw/Mn ≈ 2, thereby indicating a coordination polymerization with a single-site character of the active species.

Fractionation of chain walking polyethylene and elucidation of branching, conformation and molar mass distributions

2020 ◽  
Vol 26 (1) ◽  
pp. 47-59
Author(s):  
Laura Plüschke ◽  
Anthony Ndiripo ◽  
Robert Mundil ◽  
Jan Merna ◽  
Harald Pasch ◽  
...  
Keyword(s):  
Molar Mass ◽  
Mass Distributions ◽  
Chain Walking
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