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1.
Polymers containing intact lactone groups are a new class of macromolecules with reactive groups, which are relatively easy to obtain by polymerization, polycondensation and polyaddition, as well as by reactions on existing macromolecules. Polymers with β-lactone Groups in particular can enter into numerous addition reactions, which can be used, for example, to obtain macromolecules containing hydroxy acid or amino acid groupings. The reactions proceed under mild conditions, and can even be carried out in aqueous media, frequently giving water-soluble polymers. The polymers can be cross-linked at low temperatures, even from the aqueous phase, by the addition of bifunctional or oligofunctional reagents. Polymers containing β-lactone groups can also be used as a basis for graft co-polymers; polyester or polyether branches can be grafted on, depending on whether monomeric lactones or monomeric epoxides are used. 相似文献
2.
Jung-Sun Sohn Byung-Wook Jo Michael Hess Kirsten Schwark Stephanie Dehne Manfred Zähres 《Macromolecular Symposia》2005,225(1):31-42
The hydrophobic anti-cancer drug paclitaxel was modified with the hydrophilic poly(ethylene oxide) to a water-soluble predrug. The modification of the polymer chain results in a different solution behaviour of the macromolecules compared with the unmodified polymer. The phase diagram of the (quasi)binary system predrug-water was investigated, and molecular simulations of the predrug were executed in vacuum and in the presence of water. The results are important for further engineering on active drug systems. 相似文献
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Interpolymer complexes of poly(acrylic acid) with poly(2-hydroxyethyl acrylate) in aqueous solutions
Complexes formed from poly(acrylic acid) and poly(2-hydroxyethyl acrylate) were studied in aqueous solutions by viscometric, turbidimetric, FTIR spectroscopic, and thermogravimetric analysis methods. The formation of interpolymer complexes stabilized by hydrogen bonds was observed. It was found that the compositions of these interpolymer complexes are strongly dependent on the concentration of polymers, the order of mixing the solutions, and the pH. It was demonstrated that the complexation ability of poly(2-hydroxyethyl acrylate) is relatively low compared to other known nonionic water-soluble polymers. However, it can be significantly increased via hydrophobic modification of the poly(acrylic acid) using cetyl pyridinium bromide. 相似文献
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Dr. Philipp Keckeis Enriko Zeller Carina Jung Patricia Besirske Felizitas Kirner Dr. Cristina Ruiz-Agudo Prof. Dr. Helmut Schlaad Prof. Dr. Helmut Cölfen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(32):8283-8287
Post-polymerization modification provides an elegant way to introduce chemical functionalities onto macromolecules to produce tailor-made materials with superior properties. This concept was adapted to well-defined block copolymers of the poly(2-oxazoline) family and demonstrated the large potential of these macromolecules as universal toolkit for numerous applications. Triblock copolymers with separated water-soluble, alkyne- and alkene-containing segments were synthesized and orthogonally modified with various low-molecular weight functional molecules by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) and thiol-ene (TE) click reactions, respectively. Representative toolkit polymers were used for the synthesis of gold, iron oxide and silica nanoparticles. 相似文献
7.
A series of new amphiphilic polymers containing various amounts of N-methyl-4-vinylpyridinium units as hydrophilic part and N-dodecylacrylamide or N-decylacrylamide units as hydrophobic part have been prepared by quaternizing the cognate copolymers. Their behaviour in aqueous solutions has been studied by viscometry, as well as by fluorescence spectroscopy and tensiometry. Results are discussed in detail and a conformational model of the macromolecules at the interface (water/methylcyclohexane) is proposed in relation to the formation of microdomains in the aqueous media. 相似文献
8.
L. A. Dobrun E. L. Kuzyakina O. V. Rakitina O. Yu. Sergeeva M. E. Mikhailova N. S. Domnina A. V. Lezov 《Journal of Structural Chemistry》2011,52(6):1161-1166
Chemical modification of polyethylene glycols by antioxidants belonging to the class of sterically hindered phenols is used
to obtain water-soluble conjugates differing in the structure of the joined antioxidant and molecular weight. The inclusion
of hydrophobic end groups in polyethylene glycol molecules leads to a decrease in the lower critical mixing point of the solution
as compared to the original polymer. Dilute solution viscometry and light scattering are used to determine the molecular-mass
characteristics of the polymers and the hydrodynamic radii of single conjugate molecules. The mass fraction of single molecules
in aqueous solutions of the conjugates is greater than 95%. The aggregates are micellar-type particles whose core is formed
by the hydrophobic moieties of sterically hindered phenols. It is shown that the antiradical activity of the antioxidants
3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionic acid and 3- (3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid, which are used for the modification, differs only slightly, whereas the activity of
the relevant conjugates increases significantly. 相似文献
9.
[reaction: see text] Encapsulation data for hydrophobic hydrocarbon gases within a water-soluble hemicarcerand in aqueous solution are reported. It is concluded that hydrophobic interactions serve as the primary driving force for the encapsulation, which can be used for the design of gas-separating polymers with intrinsic inner cavities. 相似文献
10.
Helmut Ritter 《Macromolecular Symposia》1994,77(1):73-78
Comb-like polymers have been widely investigated mainly to correlate their structures with the thermal behaviour. Our interests are directed on the synthesis of new types of comb-like polymers bearing reactive groups in the side chains, main chain or as end groups. One part of the investigations deals with the behaviour of photosensible polymers containing azobenzene, cinnamic acid and mesoionic moieties. The use of enzymes as catalysts for the synthesis of new methacrylic derivatives and for the modification of polymers illustrates a fascinating contribution to polymer chemistry. The classical Diels-Alder addition was also used for the synthesis and modification of polymers. Finally, the construction of polymers containing rotaxanes in the side chains is presented. 相似文献
11.
Membrane filtration and equilibrium dialysis using Nucleopore membranes have been carried out to determine the hydrodynamic sizes of large water-soluble polymers. The macromolecules were found to have been significantly deformed even under very low stress. Multicell equilibrium was somewhat long. The hydro-dynamic radius obtained from this method was found to be in reasonable agreement with that found by ultracentrifugation and size exclusion chromatography. 相似文献
12.
Olaf Helmecke Christin Menneking Peter Behrens Henning Menzel 《Colloid and polymer science》2008,286(3):305-311
Differently shaped reaction areas for silica deposition were created by photochemical grafting of hydrophobic poly(acrylic
acid 2-ethyl-hexylester) as barrier and a hydrophilic polymer employing a mask having hexagons, pentagons, squares and stripes.
Poly(ethylene glycol), poly(acrylic acid), branched and linear poly(ethylene imine) and linear poly(methylpropylene imine)
have been applied as hydrophilic polymer in the reaction area. These patterned films have been used in silica mineralization
experiments by dipping them into a silica precursor solution. Investigations of the polymer films and silica depositions have
been done by contact angle measurements, ellipsometry and scanning electron microscopy (SEM). Silica deposition occurs only
in the hydrophilically coated areas, resulting in regular arrays of lens-like silica particles. There are only minor differences
due to the shape of the reaction area. The influence of the different hydrophilic polymers can be explained by their wetting
behaviour. 相似文献
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Caroline Duval-Terri Jovenka Huguet Guy Muller 《Colloids and surfaces. A, Physicochemical and engineering aspects》2003,220(1-3):105-115
The objective of this work was to synthesize and characterize new polymeric surfactants deriving from natural polymers and designed for membrane protein solubilization. For this purpose, a set of hydrophobically-modified pullulans (HMCMPs) of moderate molar mass and differing in hydrophobic modification ratio, charge ratio and the nature of the hydrophobic chains introduced, were prepared. Their behaviour in aqueous dilute solutions was investigated by surface tension measurement and with a polarity probe, the Coomassie Brilliant Blue dye. Two distinct critical concentrations were evidenced, demonstrating the complex behaviour of HMCMPs. Amphiphilic pullulan derivatives may indeed establish hydrophobic associations in bulk solution while adsorbing at the air water interface. The structural parameters of the polymers influence their aqueous behaviour. Self-assembly of HMCMPs occurs at smaller concentrations when the hydrophobic modification ratio or the alkyl hydrophobic chain length increases. It seems to be governed by the concentration of hydrophobic grafts, rather than by polymer concentration. Probably because of steric hindrance, 3-phenylpropyl grafts do not favour self-assembly, and lead to HMCMPs that preferentially adsorb at the air water interface. 相似文献
15.
Thermodynamic properties of binary and ternary polymer solutions (one or two uncharged polymers in one solvent) were studied. Poly(vinyl pyrrolidone) (PVP), fully hydrolyzed poly(vinyl alcohol) (PVA) homopolymers, and water-soluble poly(vinyl alcohol-co-vinyl acetal, -vinyl propional, and -vinyl butiral) copolymers with various acetal content and chain structure, respectively, were used in the experiments. The hydrophilic/hydrophobic character of the PVA-based macromolecules and their compatibility with the PVP homopolymer were systematically regulated by changing the chemical structure of the copolymers (acetal content and/or length of side chains). The water activities in binary and ternary solutions of the chemically different polymers were determined by a gel-deswelling method developed here for ternary solutions. On the basis of the Flory-Huggins theory, the relevant solvent-segment and segment-segment pair interaction parameters (chi) have been calculated. The chi12 segment-solvent interaction parameters proved to be sensitive indicators for changes in the chemical structure of the copolymers. With increase of either the acetal content or the length of side chains in the copolymer, chi12 approached the value characteristic of a theta condition. No significant differences could be revealed in the segment-segment interaction parameters obtained for the PVP-copolymer mixtures with various acetal derivatives, when the chi12 and chi13 interaction parameters determined in binary solutions were used in the calculations for chi23. Determination of the parameters chi1,23 as suggested by Panayiotou, however, showed that increasing the acetal content or the length of the hydrophobic side chains in the copolymer resulted in a reduction in the interaction between the PVA "acetals" and PVP molecules. 相似文献
16.
The synthesis of a water-soluble monomer, namely 4-vinylphenyl-d-gluco(d-manno)hexitol (4) derived from d-gluconolactone, is here presented. The homopolymerization of the vinylsugar has been conducted in both aqueous and organic media using free-radical initiators. High-molar-mass water-soluble polymers are obtained. The copolymerization behavior of the vinylphenyl sugar monomer with a hydrophilic monomer such as acrylamide, as well as with a hydrophobic monomer such as styrene, has been investigated. Statistical- and block-type copolymers have thus been prepared. The structures of the polymers were confirmed by NMR and their thermal properties examined by DSC. 相似文献
17.
V. P. Chu C. G. Overberger 《Journal of polymer science. Part A, Polymer chemistry》1985,23(9):2385-2404
In a previous paper, potassium 2-(cytos-1-yl)propanoate was grafted onto polyethylenimine of various molecular weights. These water-soluble polynucleotide analogs exhibited remarkable properties in their solution ultraviolet spectra. High hypochromicity values of 50% and 54% have been observed in alkaline aqueous solution and 50% trifluoroethanol solution, respectively. Percent hypochromicity value was observed to be directly proportional to percent graft. Red shift and hyperchromicity as a function of pH were observed for both the monomer model and the graft polymers. Light-scattering experiments on nucleic acid base grafted hydrophilic polymer backbones were carried out. Radius of gyration and second virial coefficient values indicated stiff macromolecules, rodlike in nature. Therapeutic potential of cytosyl grafted polyethylenimine was suggested by the results from continuous mixing experiments with polyinosinic acid and polyguanylic acid. Job plots showed enhanced hypochromicity, whose magnitude was dependent upon the polynucleotide and the base-base distance. 相似文献
18.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1559-1574
A series of amine functionalized polymers based on polyether backbones was prepared by the chemical modification of poly(epichlorohydrin) and poly(2-chloroethylvinyl ether). Nucleophilic substitution of pendant chloroalkyl groups offers a versatile route to prepare hydrophilic, cationic polymers. Through the choice of appropriate experimental conditions, including solvent, temperature, and amine reagent, a high degree of substitution at the chloromethyl groups can be achieved. Depending on the nature of the amine used, both water-soluble and amphiphilic cationic polymers were obtained. Crosslinked hydrogels were prepared by either subsequent crosslinking of the amine functional polyethers or by reaction of chloroalkyl polyethers with multifunctional amines. These amine functional polyethers exhibited promising bile acid sequestration properties during in vivo experiments using hamsters as animal models, providing a novel approach for treating hypercholesterolemia. Some of these polymers show efficacy superior to commercially available bile acid sequestrants. The results suggest that these novel polyammonium gels may be useful as cholesterol lowering agents. 相似文献
19.
Two-phase systems consisting of a polymer rich phase and polymer depleted phase, where the polymer is either ethyl(hydroxy
ethyl)cellulose (EHEC) or Ucon (a random copolymer of ethylene oxide and propylene oxide), have been studied. Both of these
polymers can be separated from an aqueous solution by either temperature increase or addition of cosolutes. The polymers are
thermoseparating and phase separate in water solutions at the cloud point temperature. Two types of EHEC have been studied:
one with a cloud point at 60 °C and the other at 37 °C. The Ucon polymer used in this study has a cloud point at 50 °C. Ternary
phase diagrams of polymer/water/cosolute systems have been investigated. When a strongly hydrophilic or hydrophobic cosolute
is added to an EHEC- or Ucon–water solution, a phase separation occurs already at, or below, room temperature. As cosolutes,
hydrophobic molecules like phenol, butyric and propionic acid, and hydrophilic molecules like glycine, ammonium acetate, sodium
carboxylates (acetate to valerate), were studied. The polymer rich phase formed when mixing polymer, water and cosolute was
strongly enriched or depleted with hydrophobic or hydrophilic cosolutes, respectively. The two phase region increased for
propionic acid, butyric acid and phenol as a result of increased cosolute hydrophobicity. The opposite occurred in the series
sodium acetate, sodium butyrate and sodium valerate. The effect of temperature on the phase behaviour has also been investigated.
Model calculations based on Flory–Huggins theory of polymer solutions are presented, in form of a phase diagram, which semiquantitatively
reproduce some experimental results.
Received: 5 July 1996 Accepted: 4 November 1996 相似文献
20.
A review of application of water-soluble cationic, anionic and nonionic polymers as pseudostationary phases in capillary electrophoresis (CE) and micellar electrokinetic capillary chromatography (MEKC) is presented. The effect of the structure of the polymers on the selectivity and efficiency of separation is discussed. A novel specially designed cationic polymer, 2,10-ionene, has been used for the separation of phenols. The polymer has hydrophilic and hydrophobic parts in its backbone. The polymer shows the best selectivity as a modifier in capillary zone electrophoresis (CZE)-mode, which allows the selective determination of both hydrophilic and hydrophobic phenols. 相似文献