Synthesis condition effects on the anti-polyelectrolyte behaviour of poly(acrylamide-co-(4-vinylpyridine)) (AM/4VP)copolymers in aqueous media

2020 ◽  
Vol 65 (9) ◽  
pp. 839-846
Author(s):  
Brahim BOURAS ◽  
◽  
Tayeb HOCINE ◽  
Kamel Ismet BENABADJI ◽  
Lahcene TENNOUGA ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Size Exclusion ◽  
Synthesis Conditions ◽  
Molecular Weights ◽  
Reduced Viscosity ◽  
Exclusion Chromatography ◽  
Uv Visible ◽  
Viscosity Variation ◽  
Dilute System ◽  
Poly Acrylamide

We have synthesized new copolymers AM/4VP of acrylamide (AM) and 4-vinylpyridine (4VP) in aqueous solution by radical adiabatic copolymerization. The prepared copolymers were characterised by nuclear magnetic resonance ( 1H NMR and 13C NMR), and UV -visible spectrophotometry. The molecular weights were obtained by size exclusion chromatography (SEC), and by viscosity. The reduced viscosity variation of the copolymers aqueous solutions with its concentration showed an anti-polyelectrolyte behaviour in the presence of NaCl salt. This behaviour was explained by an increase of the reduced viscosity (ηred) in dilute system. Moreover, this phenomenon depended on synthesis conditions, such as the percentage of water and 4-vinylpyridine co-monomer in the mixture at constant values of pH and temperature.

Synthesis and characterization of new, liquid, branched poly(methylvinylborosiloxanes)

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Jerzy Chruściel ◽  
Marzena Fejdyś ◽  
Witold Fortuniak
Keyword(s):  
Functional Groups ◽  
Atomic Spectroscopy ◽  
Size Exclusion ◽  
Random Structure ◽  
Molecular Weights ◽  
Chemical Structures ◽  
Siloxane Oligomers ◽  
Exclusion Chromatography ◽  
Ether Solution

Abstract New liquid branched poly(methylvinylborosiloxanes) (br-PMVBS) of random structure were synthesized in three steps. By reacting boric acid with an excess of dimethyldichlorosilane (Me2SiCl2) in dry ether a “borosiloxane precursor”: tris(chlorodimethylsilyl) borate B(OSiMe2Cl)3 was prepared. In the second step of synthesis ether solution of B(OSiMe2Cl)3 was added to a mixture of appropriate organic chlorosilanes (Me2SiCl2, MeViSiCl2, MeSiCl3, and Me3SiCl) and all reagents were reacted with stoichiometric amounts of water, in the presence of pyridine (as an acceptor of HCl), in dry ether, at low temperature (usually at -10 to 0 C). In order to fully react (“to block”) trace silanol groups, reactions of intermediate PMVBS with additional batches of Me3SiCl were carried out in the third step, C5H5N·HCl was filtered off and washed with a dry ether. The solvent was distilled off from filtrates and low molecular weight siloxane oligomers were removed by a vacuum distillation at 130-150 C. Chemical structures of br-PMVBS were confirmed by elemental analysis and spectroscopic methods (FTIR, emission atomic spectroscopy ICP-AES, and NMR: 1H, 29Si and 11B). On the basis of analysis of their 29Si-NMR spectra the microstructure of polysiloxane chains was proposed. The prepared br-PMVBS had in their structures: triple branching borosiloxane units: BO1.5 and in some cases methylsiloxane moiety CH3SiO1.5 (T). They contained linkages: Si-O-Si, Si-O-B, vinyl(methyl)siloxane functional groups (CH2=CH)MeSiO (Dvi), dimethylsiloxane mers (CH3)2SiO (D), and non-reactive trimethylsiloxy terminal groups (CH3)3SiO0.5 (M), but they did not have: hydroxyl functional groups: Si-OH and B-OH, and sensitive to water B-O-B linkages. Molecular weights of br-PMVBS (Mn = 1500-3300 g/mol; Mw = 3800-7400 g/mol) and their polydispersity (Mw/Mn = 2.0-2.5) were determined by a size exclusion chromatography (SEC).

Comparison of exopolysaccharides from mucoid and nonmucoid strains of Clavibacter michiganensis subspecies sepedonicus

1993 ◽  
Vol 39 (3) ◽  
pp. 291-296 ◽  
Author(s):  
Paul J. Henningson ◽  
Neil C. Gudmestad
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Size Exclusion ◽  
Enzyme Linked Immunosorbent Assay ◽  
Low Molecular Weight ◽  
Neutral Sugar ◽  
Clavibacter Michiganensis ◽  
Serological Reaction ◽  
Molecular Weights ◽  
Exclusion Chromatography

The exopolysaccharides produced by six strains of Clavibacter michiganensis ssp. sepedonicus were isolated and purified by liquid chromatography. Neutral sugar composition and molecular weights were determined for each polysaccharide fraction, using gas chromatography and high-performance size-exclusion chromatography. The serological reaction of each fraction was tested using enzyme-linked immunosorbent assay. Exopolysaccharide from nonmucoid strains contained only low molecular weight polysaccharides (1.5 × 103 to 1.1 × 104). Exopolysaccharide from mucoid and intermediate strains could be separated into low (4.0 × 103 to 1.1 × 104) molecular weight and high (5.0 × 105 to 1.6 × 106) molecular weight fractions. High molecular weight polysaccharides were composed almost exclusively of galactose, glucose, and fucose. The ratios of these sugars were highly variable among strains. Low molecular weight polysaccharides were primarily composed of galactose with significant and varying amounts of glucose, rhamnose, mannose, and ribose. All polysaccharide fractions except one, produced by a nonmucoid strain, reacted in the immunoassay test.Key words: exopolysaccharide, polysaccharide, Clavibacter, michiganensis, sepedonicus.

Relationships between Molecular Weights and Rheological Properties of Asphalts

1996 ◽  
Vol 1535 (1) ◽  
pp. 10-14 ◽  
Author(s):  
Jan F. B ranthaver ◽  
Raymond E. Robertson ◽  
John J. Duvall
Keyword(s):  
Molecular Weight ◽  
Rheological Properties ◽  
Size Exclusion Chromatography ◽  
Size Exclusion ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Molecular Associations ◽  
Weight Distributions ◽  
Exclusion Chromatography ◽  
Microstructural Model

It is known that the rheological properties of mixtures of organic compounds are functions of molecular weight distributions. However, with respect to asphalts, which are composed of many different compounds and compound types, molecular weights are difficult to measure. This difficulty occurs because the molecular associations that form are held together by forces of varying strengths and are partly broken up by heat and solvents. In theory, the strongest molecular associations in asphalts should have the greatest influence on the rheological properties of asphalts. These associations would be expected to be the major contributors to the asphalt's behaving as if it were a relatively high molecular weight material. Asphalt molecular associations should be isolatable by means of size exclusion chromatography. Several fractions of varying molecular weights (measured by membrane osmometry and vapor phase osmometry) were isolated from Strategic Highway Research Program (SHRP) asphalt AAD-1 by preparative size exclusion chromatography. Molecular weights of these fractions ranged from approximately 2,000 daltons to over 40,000 daltons. When these fractions were independently mixed with asphalt AAD-1 solvent moiety, mixtures were obtained whose rheological properties were a function of the molecular weights and concentrations of the associated materials. These results support the microstructural model of asphalt proposed during SHRP. The results also suggest that the unusual rheological properties of some asphalts may be explained by measuring molecular weight distributions. This type of information may be useful for modification of asphalts to achieve desirable rheological properties.

Influence of molecular structure on the rheological properties and foamability of long chain branched polypropylene by “one-pot” reactive extrusion

2020 ◽  
pp. 0021955X2094310
Author(s):  
Yan Li ◽  
Zhen Yao ◽  
Shaolong Qiu ◽  
Changchun Zeng ◽  
Kun Cao
Keyword(s):  
Coupling Reaction ◽  
Reactive Extrusion ◽  
Expansion Ratio ◽  
Size Exclusion ◽  
One Pot ◽  
Synthesis Conditions ◽  
Twin Screw ◽  
Exclusion Chromatography ◽  
In Series ◽  
Long Chain

In this work, reactive twin screw extrusion was conducted to synthesize long chain branched polypropylenes (LCB-PPs) in a “one-pot” process in which dicumyl peroxide (DCP) initiated maleic anhydride (MAH) grafting onto the linear PP, and the concomitant coupling reaction between ethylene diamine (EDA) and MAH grafted polypropylene (PP-g-MAH) proceeded in series. Fourier transfer infrared spectroscopy (FTIR) on the prepared materials confirmed the occurrence of both reactions. A series of LCB-PPs were prepared using different amounts of EDA, MAH and DCP to study their effects and determine the optimal synthesis conditions. The prepared materials were characterized by size exclusion chromatography (SEC) and rheological analysis to ascertain the polymer microstructure. The foamability of the LCB-PPs by supercritical carbon dioxide (scCO2) foaming and foam morphology were investigated. The LCB-PPs were found to have vastly improved foamability and cellular morphology. Under optimal conditions, a foam expansion ratio of over 20 was achieved.

Characterization of dissolved organic matter from Australian and Chinese source waters by combined fractionation techniques

2011 ◽  
Vol 64 (1) ◽  
pp. 171-177 ◽  
Author(s):  
Qunshan Wei ◽  
Rolando Fabris ◽  
Christopher W. K. Chow ◽  
Changzhou Yan ◽  
Dongsheng Wang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
High Performance ◽  
Size Exclusion ◽  
Rapid Urbanization ◽  
Molecular Weights ◽  
Treatment Processes ◽  
Exclusion Chromatography ◽  
Urbanization In China ◽  
Source Waters

The character of dissolved organic matter (DOM) in source waters from two countries (Australia and China) was investigated using an extended fractionation technique by combining resin adsorption, ultrafiltration and high performance size exclusion chromatography. There are distinctive chemical characteristics associated with DOM origins. Australian sourced DOM had higher hydrophobic acid (HoA) content and exhibited a more pronounced humic character, indicating a higher influence from allochthonous organics (decayed plant bodies from vegetated catchments). The higher content of hydrophobic base and neutral components found in Chinese DOM, may be attributed to the effects of increasing pollution caused by the rapid urbanization in China. The molecular weights (MWs) of aquatic HoA are predominantly in the moderate (e.g. 1–10 kDa) or small (e.g. <1 kDa) ranges. This suggests that aquatic HoA should not be assumed as high MW organics without experimental validation. It is also found that some of the low MW compounds in our samples were hydrophobic, which could explain the observation of low MW organic compounds being able to be removed by conventional treatment processes.

Combined Main- and Side-Chain Azobenzene Polyesters: A Potential For Photoinduced Nonlinear Waveguides

1999 ◽  
Vol 561 ◽  
Author(s):  
F. Sahlén ◽  
T. Geisler ◽  
S. Hvilsted ◽  
N. C. R. Holme ◽  
P. S. Ramanujam ◽  
...  
Keyword(s):  
Refractive Index ◽  
Third Harmonic Generation ◽  
Size Exclusion ◽  
Side Chain ◽  
Visible Spectroscopy ◽  
Scanning Calorimetry ◽  
Nonlinear Waveguides ◽  
Third Harmonic ◽  
Exclusion Chromatography ◽  
Uv Visible

ABSTRACTNew combined main- and side-chain azobenzene polyesters, which exhibit an intensity dependent refractive index, have been prepared in order to optically fabricate nonlinear waveguides. Novel sulfone azobenzenes, a diester, (4-[[5-(ethoxycarbonyl)pentyl]sulfonyl]-4'-[[5-(ethoxycarbonyl)pentyl]methylamino] azobenzene, and a diol, 4-[[(8-hydroxy-7-methylhydroxy)-octyl]sulfonyl]-4'-N, N-dimethylamino azobenzene, have been used to prepare new polyesters by transesterification in the molten state. The polyesters have been characterized by UV-visible spectroscopy, differential scanning calorimetry (DSC), size exclusion chromatography (SEC), third harmonic generation (THG) and optical anisotropy measurements. The molar masses of the polyesters were in the range of 5000-10000 g mol−1, which was sufficient in order to spin coat thin films. From THG measurements the polymers are shown to possess an offresonance electronic X(3) of the order 10−12 esu corresponding to a nonlinear refractive index of 2.3×10−14 cm2/W.

scholarly journals Analysis of Network Structures in Thiol-Ene UV Curing System Using Reworkable Resins

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
Haruyuki Okamura ◽  
Masashi Yamagaki ◽  
Kyohei Nakata
Keyword(s):  
Chain Length ◽  
Uv Curing ◽  
Size Exclusion ◽  
Network Structures ◽  
Thiol Compounds ◽  
Molecular Weights ◽  
Degraded Samples ◽  
Exclusion Chromatography ◽  
Chain Lengths ◽  
Acrylate Monomers

An analysis of the network structures in thiol-ene UV curing resins was carried out using reworkable resins composed of di(meth)acrylate monomers having tertiary ester linkages. The effect of the functionality of the thiols, the functional ratio of the thiol and ene functions, their conversions and curing atmosphere on the chain lengths was discussed. A mixture of (meth)acrylates, thiol compounds, a photoradical initiator, and a photoacid generator was cured by irradiation at 365 nm. The cured samples were degraded by heating after irradiation at 254 nm. Size exclusion chromatography (SEC) and 1H NMR analyses of the degraded samples were carried out after the methylation. The crosslinking conditions strongly affected the network structures. The degraded samples have molecular weights between 250 and 2700. The molecular weights of the degraded resins increased with the functionality of the thiol compounds. The chain length dependence suggests that thiol compounds with a high functionality have a low reactivity due to steric hindrance. The chain lengths of the degraded networks were nearly proportional to the concentration of the (meth)acrylate monomers. The addition of reactive diluents enhanced the reactivity and increased the chain length.

scholarly journals Synthesis and Characterization of an Iron-Containing Fatty Acid-Based Ionomer

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
David A. Stone ◽  
Atanu Biswas ◽  
Zengshe Liu ◽  
Veera Boddu ◽  
H. N. Cheng
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Raw Materials ◽  
Low Cost ◽  
Paper Industry ◽  
Alder Reaction ◽  
Size Exclusion ◽  
Molecular Weights ◽  
Exclusion Chromatography ◽  
Solid Film

One of the desirable research goals today is to convert agro-based raw materials into low-cost functional polymers. Among the readily available natural raw materials are the fatty acids that can be obtained from the hydrolysis of plant oils or from the paper industry as byproducts. In this work, a novel iron-containing ionomer has been prepared through the reaction of fatty acids with steel dust or iron powder in the presence of carbon dioxide and water. Characterization has been achieved via 1H and 13C NMR, FT-IR, and size exclusion chromatography. The product has been shown to have an ionomeric structure, consisting of oligomers of fatty acid carboxylates (derived from Diels-Alder reaction) coupled with iron(II) and iron(III) ions (from the oxidation of iron). Because the fatty acid oligomers have low molecular weights, the ionomer easily dissolves in a solvent and can be made into different physical forms, such as liquid, solid, film, or foam.

scholarly journals The Use of Epoxy Silanes on Montmorillonite: An Effective Way to Improve Thermal and Rheological Properties of PLA/MMT Nanocomposites Obtained via “In Situ” Polymerization

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Valentina Sabatini ◽  
Hermes Farina ◽  
Luca Basilissi ◽  
Giuseppe Di Silvestro ◽  
Marco A. Ortenzi
Keyword(s):  
Thermal Stability ◽  
Rheological Properties ◽  
In Situ Polymerization ◽  
Rheological Behaviour ◽  
Size Exclusion ◽  
Melt Crystallization ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Exclusion Chromatography

Polylactic acid (PLA) nanocomposites were prepared via “in situ” ring opening polymerization (ROP) of lactide using a montmorillonite, Cloisite 15A, employed after surface treatment with 3-Glycidoxypropyltrimethoxysilane. The dispersion of the nanoparticles was checked using Wide Angle X-Ray Scattering (WAXS) and Transmission Electron Microscopy (TEM); both the effects of different amounts of montmorillonite and silane were measured on molecular weights and on thermal and rheological properties, using Size Exclusion Chromatography (SEC), Differential Scanning Calorimetry (DSC), thermogravimetric analyses (TGA), and rheological analyses. It was found that even very low amounts (0.1% w/w) of nanoparticles greatly affect nanocomposites properties. Unmodified montmorillonite tends to decrease molecular weights, deactivating the catalytic system used for ROP of lactide, but when epoxy silane is present molecular weights increase. Melt crystallization temperatures increase with modified nanoparticles, which enhance crystallization process. TGA analyses show that when pure montmorillonite is present, nanocomposites have lower thermal stability with respect to standard PLA; when silane is used thermal stability can get much higher than standard PLA as silane content increases. The rheological behaviour of nanocomposites shows that melt viscosity is far higher than that of standard PLA at low shear rates and also a marked shear thinning behaviour can be achieved.

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