Polymers In Organic Solvents Research Articles

Synthesis of Soluble Complexan Polymers in Organic Solvents for Using as a Polymer–Chelate Precursor to YBa2Cu3O7-x Thin Films

Abstract A soluble complexan polymer in organic solvents, derived from 1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CyDTA), was synthesized and used as a polymer chelate precursor to YBa2Cu3O7-x thin films. Five complexan polymers (3) were prepared by a ring-opening polyaddition of CyDTA dianhydride (1) with several diamines (2). The polymer (3e) prepared with 1,2-diaminocyclohexane (2e) was soluble in water, dimethyl sulfoxide (DMSO), methanol, and ethanol. A clear aqueous solution (pH 8) containing 3e and 1/2 equivalent molar amount of metal nitrates of Y, Ba, and Cu (1 : 2 : 3 in molar ratio) was poured into tetrahydrofurane (THF) to precipitate a polymer–metal chelate. The chelate formations of each metal were confirmed by C=O stretching bonds. The polymer chelate precursor was soluble in methanol, DMSO, and water, and partially soluble in ethanol. The polymer–metal chelate was dissolved in methanol, of which the metal concentration was adjusted to 3 wt%. This solution was spin-coated onto SrTiO3 (100) and MgO (001) substrates for preparing YBa2Cu3O7-x thin films. According to an X-ray diffraction analysis, YBa2Cu3O7-x film with a c-axis orientation was formed on a SrTiO3 substrate; even the precursor film was sintered at 780 °C for 1 h under air. Superconducting YBa2Cu3O7-x films with a c-axis orientation were also prepared on a MgO (001) substrate.

A novel one-concentration method for improved multi-angle laser light scattering

A novel data interpretation method is presented which is derived from weighted least squares analysis. Given the steep dependence of the Rayleigh factor on concentration, a Zimm-plot based regression of weight average molar mass and the RMS radius of gyration is strongly influenced by data over an optimum concentration range, which can be quite narrow for some polymer-solvent combinations. The “one-concentration method” exploits this sensibility to improve the precision in molar mass and radius of gyration measurements to ±4%. The theoretical prediction of the optimum concentration is included. The one-concentration method is applied to polymers in organic solvents as well as to water-soluble polyelectrolytes.

Solid-state conjugation of proteins with hydrophobic compounds in non-denaturing conditions: I. Acylation of proteins by dansyl proline using a polymeric N-hydroxysuccinimide ester

A method of conjugating protein molecules under native conditions with water-insoluble hydrophobic compounds is developed. It permits very water-insoluble acids to be gently coupled to the primary amines on proteins or other biopolymers. For this purpose we synthesized a polymer (co-polymer of N-hydroxymaleimide and N-vinylpyrrolidone cross-linked by benzidine) which swells equally well in water and in organic solvents. Hydrophobic substances are first activated by esterification to this polymer in organic solvent and then conjugated to protein by acylation in aqueous medium at pH 8.0–8.5. Thus, the contact of native protein with organic co-solvent may be completely avoided. The application of this approach is demonstrated by labeling trypsinogen and plasminogen with dansyl proline.

A new method for preparing biodegradable microparticles and entrapment of hydrocortisone in dl-PLG microparticles using supercritical fluids

An improved process for the production of polymeric microparticles, based on solution-enhanced dispersion by supercritical fluids (SEDS) using a combination of supercritical N 2 and CO 2, was evaluated. The biodegradable polymers, poly( d,l-lactide-co-glycolide): copolymer composition 50:50 ( dl-PLG), poly( l-lactide) ( l-PLA), poly( d,l-lactide) ( dl–PLA) and polycaprolactone, were used for preparation of microparticles by a modified SEDS process. Solutions of the polymers in organic solvents were dispersed and the solvent was extracted with supercritical CO 2 and N 2. The morphology, the size distributions and degree of hydrocortisone entrapment were determined. The combination of supercritical N 2 and CO 2 led to a more efficient dispersion of the polymer solutions than CO 2 alone. This resulted in a reduction of particle size of the microparticles produced from all of the amorphous polymers. Discrete spherical microparticles with a mean volumetric diameter of less than 10 μm were produced from dl-PLG, dl–PLA and L–PLA. Hydrocortisone was successfully entrapped within the dl-PLG microparticles. The modified SEDS process improved the dispersion of amorphous polymer solutions resulting in formation of small spherical microparticles. The SEDS process can be used for incorporation of drugs into the dl-PLG microparticles.

Pressure- and Temperature-Induced Transitions in Solutions of Poly(dimethylsiloxane) in Supercritical Carbon Dioxide

Supercritical fluids (SCFs) have great technological potential for minimizing the organic wastes associated with polymer manufacturing and processing. However, significant challenges remain for developing the same level of understanding of the behavior of polymers in SCFs as has been reached for polymers in traditional organic solvents. Small-angle neutron scattering was used to study the effect of pressure and temperature on the phase behavior of poly(dimethylsiloxane) (PDMS) in supercritical carbon dioxide (SC CO2). It was demonstrated that PDMS−SC CO2 solutions reproduce all main features of the temperature−concentration phase diagram for polymers in organic solvents. Moreover, because of their continuously adjustable solubility, SCFs exhibit novel effects, such as a pressure-induced transition to the ϑ point and to the good solvent domain, in addition to a polymer−solvent demixing at a lower critical solution pressure.

Preparation of biodegradable microparticles using solution-enhanced dispersion by supercritical fluids (SEDS).

We have evaluated a new process, involving solution-enhanced dispersion by supercritical fluids (SEDS), for the production of polymeric microparticles. The biodegradable polymers, Poly (DL-lactide-co-glycolide): copolymer composition 50:50 (DL-PLG), Poly (L-lactide) (L-PLA), Poly (DL-lactide) (DL-PLA) and Polycaprolactone (PCL), were used for preparation of microparticles using SEDS. Solutions of the polymers in organic solvents were dispersed and sprayed with supercritical CO2. Extraction of the organic solvents resulted in the formation of solid microparticles. The amounts of highly toxic solvents such as dichloromethane (MC) were reduced in the process. Microparticles were obtained from all polymers. The mean particle size and shape varied with the polymer used. The morphology of the particles was strongly affected by the choice of polymer solvent. Discrete spherical microparticles of DL-PLG were produced with a mean volumetric diameter of 130 microm. The microparticles of the L-PLA were almost spherical, and their size increased from 0.5 to 5 microm as the density of supercritical CO2 decreased. PCL formed microparticles with diameters of 30-210 microm and showed a strong tendency to form films at high pressure. The SEDS process appears a promising method for production of microparticles from biodegradable polymers without the use of toxic solvents.

Laser performance studies of para-(phenylene-ethynylene) polymers in organic solvents

The lasing performance of the polymers poly(2,5-dioctadecyloxy-paraphenylene-ethynylene-co-2,5-thienyl) (OPT) and poly(2,5-dioctadecyloxy-paraphenylene-ethynylene-co-2,5-pyridinyl) (OPP) in organic solvents was studied. A two-mirror resonator was transversally pumped using single pulses of the second harmonic of a mode-locked ruby laser. OPT in tetrahydrofuran lased in the region from 480 nm to 525nm and OPP in tetrahydrofuran showed laser action in the region from 460 nm to 490nm. The polymer solutions are characterized by absorption and fluorescence spectroscopic analysis. Effective stimulated emission cross-sections are reported. High excited-state absorption cross-sections and residual ground-state absorption reduce the lasing efficiency.

Radiation preparation of the water-soluble, temperature sensitive polymers in organic solvents

In this work, a water-soluble, temperature sensitive linear polymer, polyN-isopropylacrylamide(poly-NIPAAm) was synthesized by means of γ radiation induced polymerization in mixed solvent of water-tetrahydrofuran(THF) and several organic solvents. When mixed solvent of H 2O-THF was used, with the increasement of the content of H 2O in the mixed solvent, especially from 60% to 100%, the molecular weight of polyNIPAAm could be raised from ten thousand to nearly one million. Besides THF, some other organic solvents such as methanol, ethanol, dichloromethane, chloroform, tetrachloromethane, acetone, methylisobutylketone(MIBK) and 1,4-dioxane were used. Then the white power product of polyNIPAAm with different molecular weight can be synthesized. PolyNIPAAm synthesized in this work was tried to use in concentration of metal ions in aqueoes solution. Concentration effect of Au 3+ was obviously. It has no tangible proofs for UO 2 2+ with large ion radius, but for the U 4+ and some rare-earth ions, the concentration effects were obtained in different degrees.

Negative thixotropy of solutions of partially hydrolyzed polyacrylamide

We found that the character of negative thixotropy of partially hydrolyzed polyacrylamide in aqueous glycerol strongly depends on polymer concentration, glycerol content and shear rate applied. At low polymer and glycerol concentrations, shear stress and viscosity slowly increased during shearing to a limiting value. In addition to this behavior, a steep increase in shear stress as well as normal stress followed by their pronounced oscillations occurred at higher concentrations of both components and at higher shear rates. Similarly to the negative thixotropic effect in solutions of other polymers in organic solvents, the hydrodynamic conditions in which the effects set in seem to be controlled by the shear stress acting in the flowing solution; initial kinetics of the effect depends on solvent viscosity and shear stress applied. To explain the influence of the glycerol content and degree of ionization of the polymer on the minimum shear stress at which the effect sets in, a decisive role of intermolecular electrostatic repulsions in association of the polymer molecules in shear field is assumed.

Synthesis of protein‐containing polymers in organic solvents

Subtilisin has been modified with polyethylene glycol (PEG) monomethacrylate (MW 8000) by reductive alkylation, and incorporated into polymethyl methacrylate durring free-radical initiated polymerization. The activity and stability of the PEG-modified enzymes have been determined in aqueous buffer and organic solvents. The K(m) and V(max) values for unmodified, singly and doubly modified subtilisin were compared in these environments, and the half-lives of both modified enzymes were remarkably high (up to 2 months). The protein-containing polymer was analyzed for activity and polymer properties, and our results indicate that active subtilisin can be incorporated into polymethyl methacrylate during polymerization in organic solvents while retaining its activity and stability. (c) 1995 John Wiley & Sons, Inc.

Flow field-flow fractionation of polymers in organic solvents

Previous flow field-flow fractionation (FIFFF) studies have used aqueous mobile phases in separations, thereby limiting the applicability of the method. We now have performed FIFFF with totally organic mobile phases, so that organic-soluble synthetic polymers can be characterized with this appraoch. Mixtures of poly(ethylene oxide) standards were fractionated in a channel using an unmodified regenerated cellulose ultrafiltration membrane with methanol as the mobile phase

Living polymers in organic solvents

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLiving polymers in organic solventsP. Terech, V. Schaffhauser, P. Maldivi, and J. M. GuenetCite this: Langmuir 1992, 8, 9, 2104–2106Publication Date (Print):September 1, 1992Publication History Published online1 May 2002Published inissue 1 September 1992https://doi.org/10.1021/la00045a007RIGHTS & PERMISSIONSArticle Views272Altmetric-Citations63LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (388 KB) Get e-Alerts Get e-Alerts

Spontaneous film formation from a polymer solution

An unusual continuous film formation process of lateral pentyloxy substituted poly(p-phenylene terephthalate)s (s-PPPT) and poly(carbonate) (PC) is observed. A liquid film of polymer solution creeps over the surface of water dropped into the polymer solution. By vaporization of the solvent a solid polymer film is formed on the water surface and can be removed. The driving force for the film formation mechanism is assumed by the reduction of the surface tension of water. Experiments verify this mechanism by increasing the film formation speed using a gas stream, by reducing the formation speed through lowering the surface tension by rinsing agents, and by lowering the solubility of the polymer. As expected, no effects are found by variation of the pH-value of water. Necessary conditions for the film formation process are: good solubility of the polar polymers in organic solvents having a high vapor pressure, complete phase separation, solution density higher than water density, and a surrounding gas phase unsaturated with solvent vapor.

Partition of hydrophobic compounds between two liquid phases of similar hydrophobicity

Liquid-liquid two-phase systems have been attained by dissolving pairs of polymers in organic solvents with or without the addition of water. The solvents include dioxane, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulphoxide and acetonitrile. The compositions of the phases have been determined in some cases. Phases (in equilibrium) with nearly the same ratio between the organic solvent and water have been obtained. Hydrophobic compounds have been partitioned within two-phase systems containing dimethylformamide. One of these systems has been used for fractionation of zein (from corn) by counter-current distribution.

Blood interactions with novel polyurethaneurea hydrogels

The influence on blood of polyurethaneurea hydrogels in vitro was investigated based on poly(ethylene oxide). A hydrogel was compared with the regenerated cellulose membrane Cuprophan in terms of complement activation, as determined by measurement of C3a concentration. The hydrogel induced less complement activation and the presence of poly(ethylene oxide) is likely to be beneficial to platelet reactivity. The ability to vary the polymer composition and the solubility of the polymers in organic solvents makes the polyurethaneurea hydrogels strong candidates for composite biomaterials.

導入率を制御したアミノ化ポリスチレンの合成とその成膜性

Polymers containing amino group were investigated to be used as biomaterials. Amination of polystyrene was carried out two steps ; nitration by nitric acid and acetic anhydride in carbon tetrachloride, and then reduction of nitro group with tin (II) chloride. The degree of nitro group introduced in polystyrene can be controlled by adjusting the amount of nitric acid. Then the solubility of these polymers in organic solvents was examined, and the processability of membrane prepared using the solution casting method was evaluated. The conditions of membrane preparation, e. g. the time of solvent evaporation, polymer concentration in the solution and the kind of coagulating solvents, affected to the physical structure of the membrane. Each membrane prepared was that of spongy structure entirely. Thus, these membranes are expected to be applied as biomaterials, e. g. antithrombogenic membrane by immobilization of heparin and membrane reactor with enzymes.

A method for measuring swelling kinetics and volume contraction of polymers

A method has been developed for continuously measuring the volume of a polymer solution during its formation. Anomalous changes in solution volume and density were observed in various stages of swelling of crystalline polymers in organic solvents. The anomalies are assumed to stem from mechanical stress induced by the as yet non-swollen central regions, from the stabilizing effect of the network of crystallites, and also from additional, solvent-induced crystallization.

Enhanced sensitivity in the electron beam resist poly(methyl methacrylate) using improved solvent developer

Poly(methyl methacrylate) (PMMA) has been used widely as a positive working resist in electron beam lithography, and so the solubility of this polymer in organic solvents increases upon exposure to electron beam irradiation. Considerable efforts have been directed towards increasing the sensitivity of this resist to electron beam irradiation, but only a few have focused on careful and proper solvent selection for the development process. In this study we have investigated the way in which the selection of the best solvent or combinations of solvents can lead to a significant improvement in resist performance by influencing both the sensitivity and the contrast on development. The solubility of PMMA in cosolvent and solvent-precipitant systems has been examined, and a number of developers were chosen which fulfilled the basic requirement that the observed pattern distortion was minimized on exposure to the developer. Comparison with the standard developer for PMMA, which is a mixture of methyl isobutyl ketone and isopropyl alcohol (1:3), showed that an improved sensitivity of at least threefold was achieved when isopropyl alcohol and water (9:1) was used as a developer. This enhancement in sensitivity was achieved at the expense of an increase in the development time to about 4–5 min. On the other hand, the development time could be greatly reduced by using a developer selected from solvent-precipitant systems.

Group Transfer and Cationic Polymerization of 1-Butadienyloxytrimethylsilane

As requirement for the synthesis of new C4-type periodic polymers, group transfer polymerization of 1-butadienyloxytrimethylsilane (BdTMS) was examined. Equimolar Benzaldehyde (BAld)–ZnCl2 catalysts in benzene at 20°C were effective to give a soluble polymer in organic solvents. The structure of the polymer was revealed by NMR and IR analyses as 1,4-trans addition mode of diene. Dispersities (Mw/Mn) of molecular weight distribution evaluated by GPC reduced to about 1.5, clearly differing from about 3 in the case of ZnCl2 alone. SnCl4 or (C2H5)3Al2Cl3 without BAld polymerized BdTMS rapidly, accompanying gelation even at −78°C. Living propagation in BdTMS/BAld/ZnCl2 system was confirmed by the incremental monomer addition method. In NMR-monitoring the equimolar reaction of BdTMS/BAld catalyzed by ZnCl2 in C6D6, it was found that an aldol adduct appeared at the first stage and then a formyl group regenerated in the adduct began to react with the monomer.

Solvation stabilization of vinyl chloride polymers to degradation in solution

The rates of thermal degradation of vinyl chloride (VC) polymers in organic solvents and in the solid phase are significantly different. The kinetics of the process in the liquid phase is determined by the effects of specific and non-specific solvation interaction between the solvent and the polymer molecules. In the process of polymer degradation, solvation has different effects on the rate of random elimination of HCl from PVC with the formation of isolated CC bonds and on the formation of poly-conjugated systems of double bonds. The rates of liquid-phase degradation of VC polymers in different classes of organic solvents are mainly determined by specific polymer-solvent solvation interaction; the overall dehydrochlorination rates of VC polymers in solution increase linearly with the basicity B (donor number D N ) of a solvent: In addition to specific solvation, the rate of the liquid phase degradation of VC polymers in solvents is also affected by polymer-solvent non-specific interaction. The loosening of solvation interactions between polymer and solvent, resulting from addition of a non-polar hydrocarbon to the system, induces stabilization in solutions of VC polymers.