scholarly journals Star-Shaped Polydimethylsiloxanes with Organocyclotetrasilsesquioxane Branching-Out Centers: Synthesis and Properties

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 285
Author(s):  
Yulia S. Dyuzhikova ◽  
Anton A. Anisimov ◽  
Alexander S. Peregudov ◽  
Mikhail I. Buzin ◽  
Galina G. Nikiforova ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Gel Permeation Chromatography ◽  
Physicochemical Analysis ◽  
Langmuir Trough ◽  
Scanning Calorimetry ◽  
Gel Permeation ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

New non-crystallizable low-dispersity star-shaped polydimethylsiloxanes (PDMS) containing stereoregular cis-tetra(organo)(dimethylsiloxy)cyclotetrasiloxanes containing methyl-, tolyl- and phenyl-substituents at silicon atoms and the mixture of four stereoisomers of tetra[phenyl(dimethylsiloxy)]cyclotetrasiloxane as the cores were synthesized. Their thermal and viscous properties were studied. All synthesized compounds were characterized by a complex of physicochemical analysis methods: nuclear magnetic resonance (NMR), FT-IR spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), viscometry in solution, rheometry, and Langmuir trough study.

scholarly journals Structural and Thermal Characterization of Novel Organosolv Lignins from Wood and Herbaceous Sources

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 860 ◽  
Author(s):  
Anna Trubetskaya ◽  
Heiko Lange ◽  
Bernd Wittgens ◽  
Anders Brunsvik ◽  
Claudia Crestini ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Gel Permeation Chromatography ◽  
Thermal Characterization ◽  
Structural Features ◽  
Isolation Method ◽  
Structural Variations ◽  
Gel Permeation ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

This study demonstrates the effects of structural variations of lignins isolated via an organosolv process from different woody and herbaceous feedstocks on their thermal stability profiles. The organosolv lignins were first analysed for impurities, and structural features were determined using the default set of gel permeation chromatography, FT-IR spectroscopy, quantitative 31 P NMR spectroscopy and semi-quantitative 1 H- 13 C HSQC analysis. Pyrolysis-, O 2 - and CO 2 -reactivity of the organosolv lignins were investigated by thermogravimetric analysis (TGA), and volatile formation in various heating cycles was mapped by head-space GC-MS analysis. Revealed reactivities were correlated to the presence of identified impurities and structural features typical for the organosolv lignins. Data suggest that thermogravimetric analysis can eventually be used to delineate a lignin character when basic information regarding its isolation method is available.

GROWTH AND STUDIES OF PROPERTIES OF COPPER SUCCINATE DIHYDRATE SINGLE CRYSTALS

2013 ◽  
Vol 27 (11) ◽  
pp. 1350073
Author(s):  
M. P. BINITHA ◽  
P. P. PRADYUMNAN
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dielectric Constant ◽  
Single Crystals ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Different Temperatures ◽  
Triclinic Structure ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Single crystals of copper succinate dihydrate (CSD) with triclinic structure were grown in silica gel medium. The functional groups in the crystal were analyzed by FT-IR Spectroscopy. Atomic Force Microscopy (AFM) revealed the striations on the surface of grown crystals, which were incorporated during its time of growth. Thermal degradation studies have been carried out by Differential Scanning Calorimetry (DSC). Dielectric constant and AC conductivity have been estimated as a function of frequency at different temperatures.

scholarly journals A New Strategy for the Synthesis of Hydroxyl Terminated Polystyrene-b-Polybutadiene-b-Polystyrene Triblock Copolymer with High Cis-1, 4 Content

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 598 ◽  
Author(s):  
Xin Min ◽  
Xiaodong Fan
Keyword(s):  
Triblock Copolymer ◽  
Gel Permeation Chromatography ◽  
Hydroxyl Group ◽  
The Novel ◽  
Scanning Calorimetry ◽  
Gel Permeation ◽  
New Strategy ◽  
Ft Ir ◽  
Novel Catalyst ◽  
Lower Glass Transition Temperature

This work reports the preparation of a hydroxyl terminated polystyrene-b-polybutadiene-b-polystyrene triblock copolymer (SBS) with high cis-1, 4 content via a novel nickel catalyst, [η3-Ni(CH2CHCHCH2OOCH3)][BPhF4]. FT-IR, 1H-NMR, and 13C NMR indicated that the polybutadiene segment of the copolymer contains greater than 90% cis-1, 4 structure, indicating achievement of the objective. Toward the functionalization goal, a hydroxyl group was successfully introduced at the end of the triblock copolymer (HO–SBS–OH). The results of gel permeation chromatography (GPC) revealed that the polymer is indeed a triblock copolymer, with no traces of homopolymer. Differential scanning calorimetry (DSC) showed that HO–SBS–OH synthesized using the novel catalyst had a lower glass transition temperature (Tg) than HO–SBS–OH synthesized with an alkyl lithium catalyst. Therefore, the polymer synthesized via the novel catalyst contains high cis-1,4 content and displays excellent low-temperature mechanical properties.

scholarly journals A New Method for Synthesis of Poly(2,6-dimethyl-1,4-phenylene oxide) and Poly(2,6-diphenyl-1,4-phenyl oxide)

2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Naser M. Al Andis
Keyword(s):  
Differential Scanning Calorimetry ◽  
Nmr Spectroscopy ◽  
Microwave Heating ◽  
Molar Mass ◽  
Gel Permeation Chromatography ◽  
High Yield ◽  
Scanning Calorimetry ◽  
Phenylene Oxide ◽  
Gel Permeation ◽  
Amine Complex

The polymerization of two monomers 2,6-dimethylphenol and 2,6-diphenylphenol was carried out by an oxidative route in the presence of Cu(I) as a catalyst and amine complex as a solvent assisted by microwave heating. The synthesized polymers were characterized by NMR spectroscopy, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). It was observed that this process of polymerization gives high yield (98 wt%) of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and poly(2,6-diphenyl-1,4-phenylene oxide) (PPPO) with a molar mass of 1180 (M¯n), 1400 (M¯w) and 28000 (M¯n), 46500 (M¯w) gm/mol, respectively. A negligible amount of diphenoquinone was also observed and its dispersity was rather moderate, 1.17 and 1.68, respectively.

Changes of Corn Flour by Different Treatments

2012 ◽  
Vol 554-556 ◽  
pp. 1017-1020
Author(s):  
De Jing Wang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Gel Permeation Chromatography ◽  
Bimodal Distribution ◽  
Wet Milling ◽  
Corn Flour ◽  
Scanning Calorimetry ◽  
Gel Permeation ◽  
Chain Lengths

The properties of corn flour prepared by fermenting, wet-milling and extruding were investigated. The results showed that RVA parameters of the corn flours by fermenting compared with wet-milling decreased but enthalpies slightly increased. Extruded samples had no peak (RVA) and no differential scanning calorimetry (DSC) endotherm. In fermenting and wet milling starches a bimodal distribution of chain lengths( fractionⅠand Ⅱ) were found by gel permeation chromatography but extruded starches only one fraction.

scholarly journals 1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions

2013 ◽  
Vol 9 ◽  
pp. 647-654 ◽  
Author(s):  
Astrid Hoppe ◽  
Faten Sadaka ◽  
Claire-Hélène Brachais ◽  
Gilles Boni ◽  
Jean-Pierre Couvercelle ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Solvent Free ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Solvent Free Conditions ◽  
Gel Permeation

The ring-opening polymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA) under solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as precatalyst is described. Linear and star-branched polyesters were synthesized by successive use of benzyl alcohol, ethylene glycol, glycerol and pentaerythritol as initiator alcohols, and the products were fully characterized by 1H and 13C{1H} NMR spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). BMIM-2-CO2 acts as an N-heterocyclic carbene precursor, resulting from in situ decarboxylation, either by heating under vacuo (method A) or by addition of NaBPh4 (method B). Possible catalytic and deactivation mechanisms are proposed.

Synthesis and Characterization of Triethanolamine Borate

2013 ◽  
Vol 709 ◽  
pp. 28-31
Author(s):  
Cheng Xue Wang ◽  
Tian Tian Liang ◽  
Chun Qiao Wei
Keyword(s):  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Synthesis And Characterization ◽  
Spectroscopy Analysis ◽  
Scanning Calorimetry ◽  
Reaction Conditions ◽  
Different Types ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Starting with boric acid and triethanolamine , the effect of the different types of the water-carrying agent on the yield was invested, and influences of dosage of water-carrying agent ,the mole ratio of reactants, reaction time on yield were discussed, the optimized reaction conditions were confirmed. The structure of the product was described by Fourier transform-infrared (FT-IR) spectroscopy, NMR Spectroscopy analysis, mass spectrometry (MS) and thermodynamic properties was analyzed by differential scanning calorimetry (DSC) and thermogravimetry (TG).

Lipase-catalyzed synthesis and post-polymerization modification of new fully bio-based poly(hexamethylene γ-ketopimelate) and poly(hexamethylene γ-ketopimelate-co-hexamethylene adipate) copolyesters

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 214-225
Author(s):  
Wan-Xia Wu
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Immobilized Lipase ◽  
Thermal Characterization ◽  
Aliphatic Polyester ◽  
Scanning Calorimetry ◽  
Temperature Time ◽  
Polymerization Conditions

AbstractA novel full bio-based ketone-containing aliphatic polyester was prepared by enzyme-catalyzed polycondensation of diethyl γ-ketopimelate (DEK) with 1,6-hexanediol (HDO) using immobilized lipase B from Candida antarctica (CALB). The influences of polymerization conditions such as temperature, time, enzyme amount, and solvent amount on the molecular weight of poly(hexamethylene γ-ketopimelate) (PHK) were investigated. New fully bio-based poly(hexamethylene γ-ketopimelate-co-hexamethylene adipate) (poly(HK-co-HA)) copolymers with narrow polydispersity and well-defined composition were synthesized by copolymerization of DEK, HDO, and diethyl adipate. The structures of PHK and poly(HK-co-HA) copolymers were characterized by nuclear magnetic resonance, and their thermal characterization was examined by thermogravimetric analysis and differential scanning calorimetry. The degradation of PHK and poly(HK-co-HA) copolymers was studied. The post-polymerization modification of these polyketoesters via oxime click chemistry was further demonstrated.

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