L'invention concerne des materiaux poreux solides presentant une structure coeur-ecorce a base de polymeres et/ou de biopolymeres synthetiques (A) qui sont solubles dans des liquides chaotropes (C) et insolubles dans des liquides...
moreL'invention concerne des materiaux poreux solides presentant une structure coeur-ecorce a base de polymeres et/ou de biopolymeres synthetiques (A) qui sont solubles dans des liquides chaotropes (C) et insolubles dans des liquides inorganiques polaires protogenes (D1) et dans des liquides organiques polaires protogenes (D2). L'invention concerne egalement des procedes permettant de les produire et leur utilisation.
Verfahren zur Herstellung von wassrigen Dispersionen vn Polyelektrolytkomplexen durch turbulentes Mischen von wassrigen Losungen von anionischen Polymerisaten mit einer Ladungsdichte von mindestens 5 meq/g mit wassrigen Losungen von...
moreVerfahren zur Herstellung von wassrigen Dispersionen vn Polyelektrolytkomplexen durch turbulentes Mischen von wassrigen Losungen von anionischen Polymerisaten mit einer Ladungsdichte von mindestens 5 meq/g mit wassrigen Losungen von kationischen Polymerisaten mit einer Ladungsdichte von mehr als 4 meq/g und Verwendung der so erhaltlichen wassrigen Dispersionen von Polyelektrolytkomplexen oder der daraus isolierten Polyelektrolytkomplexe als Zusatz zum Papierstoff zur Herstellung von Papier mit erhohter Nassfestigkeit, als Fixiermittel, Flockungs- und Retentionsmittel, Entwasserungsmittel fur Schlamme, als Zusatz zu Waschmitteln, Klebstoffen, kosmetischen Erzeugnissen wie Shampoos und Hairkonditionern, Beschichtungsmitteln fur Leder, textile Gewebe, Cellulosefasern, Baumwolle, Glas, Keramik und Metalle sowie als Carrier und/oder Schutzkolloid fur Arzneimittel, Agrochemikalien sowie in der menschlichen und tierischen Ernahrung.
Verfahren zur Herstellung von Karton fur die Verpackung von Flussigkeiten durch Masseleimung einer wassrigen Aufschlammung von Cellulosefasern mit mindestens einem Leimungsmittel in Gegenwart mindestens eines Retentionsmittels und...
moreVerfahren zur Herstellung von Karton fur die Verpackung von Flussigkeiten durch Masseleimung einer wassrigen Aufschlammung von Cellulosefasern mit mindestens einem Leimungsmittel in Gegenwart mindestens eines Retentionsmittels und gegebenenfalls einer wasserloslichen Aluminiumverbindung, wobei man zu der wassrigen Aufschlammung von Cellulosefasern zusatzlich mindestens ein kationisches Polymer zusetzt und Verwendung eines so hergestellten Kartons zur Herstellung von Verpackungen von Flussigkeiten.
Recent work on the crystallisation of inorganic crystals under compressed monomolecular surfactant films has shown that two dimensional templates can be used to promote the oriented nucleation of solids. When a suitable long alkyl chain...
moreRecent work on the crystallisation of inorganic crystals under compressed monomolecular surfactant films has shown that two dimensional templates can be used to promote the oriented nucleation of solids. When a suitable long alkyl chain surfactant is cast on the crystallisation media a monodispersied population of crystals forms exclusively at the monolayer/solution interface. Each crystal is aligned with a specific crystallographic axis perpendicular to the plane of the monolayer suggesting that nucleation is facilitated by recognition events between the nascent inorganic solid and the organic template.For example, monolayers of the long alkyl chain surfactant, stearic acid will promote the oriented nucleation of the calcium carbonate polymorph, calcite, on the (100) face, whereas compressed monolayers of n-eicosyl sulphate will induce calcite nucleation on the (001) face, (Figure 1 & 2). An extensive program of research has confirmed the general principle that molecular recognitio...
.This presentation will first address the physico-chemical properties of the weak polyelectrolytes, poly(vinyl amine) [PVAm] and poly(ethylene imine) [PEI] will be discussed; PVAm being a relatively new, versatile and poorly characterised...
more.This presentation will first address the physico-chemical properties of the weak polyelectrolytes, poly(vinyl amine) [PVAm] and poly(ethylene imine) [PEI] will be discussed; PVAm being a relatively new, versatile and poorly characterised material compared to the classic PEI. Molecular properties are of immense importance in the understanding of polymer performance in a wide range of applications. Details of the charging of both polymers’ will be given and a comparison will be drawn between the two polyelectrolytes. Charge density variation as a function of simple solution parameters for various molecular structures will be discussed and explained with reference to the Ising model 4 . The variation of polymer conformation as a function of solution conditions such as ionic strength and pH will also be discussed. Results on the non-equilibrium adsorption of the polymers onto various substrates at short polymer-substrate contact times will be given. The industrial application of the polyelectrolytes will be discussed with reference to specific examples, as will the optimisation of polymer performance via structural tailoring. Finally, potential applications of PVAm and PEI, as well as other polyelectrolytes, in nanotechnology will be
Aqueous dispersions of polymers which are obtainable by free radical suspension polymerization of ethylenically unsaturated monomers in an oil-in-water emulsion whose disperse phase comprises at least one fluorescent dye dissolved in at...
moreAqueous dispersions of polymers which are obtainable by free radical suspension polymerization of ethylenically unsaturated monomers in an oil-in-water emulsion whose disperse phase comprises at least one fluorescent dye dissolved in at least one ethylenically unsaturated monomer and having an average particle diameter of at least 1 micron, in presence of at least one surface-active compound and at least 0.5 wt .-%, based on the monomers, of at least one hydrophobic, non-polymerizable organic compound of a hydrophobic polymer from at least one C A process for preparing these dispersions and Use of aqueous dispersions of polymers which are obtainable by free radical suspension polymerization or by free-radical miniemulsion polymerization of ethylenically unsaturated monomers in an oil-in-water emulsion whose disperse phase comprises at least one fluorescent dye dissolved in at least one ethylenically unsaturated monomer, and a mean particle diameter of comprises at least 100 nm, in t...
L'invention concerne un procede de fabrication de papier, de carton et de carton epais par addition (i) d'au moins un agent de retention et (ii) de microparticules organiques, ioniques, non-reticulees, insolubles dans l'eau,...
moreL'invention concerne un procede de fabrication de papier, de carton et de carton epais par addition (i) d'au moins un agent de retention et (ii) de microparticules organiques, ioniques, non-reticulees, insolubles dans l'eau, presentant une granulometrie moyenne inferieure a 500 nm et une teneur en monomeres ioniques, introduits par polymerisation, inferieure a 1 % en poids, ou de microparticules organiques, non-reticulees, insolubles dans l'eau, presentant une granulometrie moyenne inferieure a 500 nm et une teneur maximale en monomeres ioniques, introduits par polymerisation, de 10 % en poids, pouvant etre obtenues par polymerisation des monomeres en presence de silice, de verre soluble, de bentonite et/ou de melanges de celles-ci, a de la pâte a papier, et deshydratation de la pâte a papier sur un tamis.
Die Erfindung betrifft zur Herstellung kunstlicher Gewebe geeignete Polymergeruste, insbesondere Polysaccharidgeruste, Verfahren zu ihrer Herstellung, ihre Verwendung zur Herstellung kunstlicher Gewebe sowie auf der Basis solcher...
moreDie Erfindung betrifft zur Herstellung kunstlicher Gewebe geeignete Polymergeruste, insbesondere Polysaccharidgeruste, Verfahren zu ihrer Herstellung, ihre Verwendung zur Herstellung kunstlicher Gewebe sowie auf der Basis solcher Polymergeruste hergestellte kunstliche Gewebe.
Mutagens like oxidants cause lesions in the DNA of ovarian and fallopian tube epithelial cells, resulting in neoplastic transformation. Reduced exposure of surface epithelia to oxidative stress may prevent the onset or reduce the growth...
moreMutagens like oxidants cause lesions in the DNA of ovarian and fallopian tube epithelial cells, resulting in neoplastic transformation. Reduced exposure of surface epithelia to oxidative stress may prevent the onset or reduce the growth of ovarian cancer. Lycopene is well-known for its excellent antioxidant properties. In this study, the potential of lycopene in the prevention and treatment of ovarian cancer was investigated using an intraperitoneal animal model. Lycopene prevention significantly reduced the metastatic load of ovarian cancer-bearing mice, whereas treatment of already established ovarian tumors with lycopene significantly diminished the tumor burden. Lycopene treatment synergistically enhanced anti-tumorigenic effects of paclitaxel and carboplatin. Immunostaining of tumor and metastatic tissues for Ki67 revealed that lycopene reduced the number of proliferating cancer cells. Lycopene decreased the expression of the ovarian cancer biomarker, CA125. The anti-metastatic...
On 31st March 2003 Advanced Tissue Sciences (ATS) was liquidated, with the effect that in excess of US$300 million of stakeholder financing was destroyed. Although successful in the development of breakthrough technologies in the...
moreOn 31st March 2003 Advanced Tissue Sciences (ATS) was liquidated, with the effect that in excess of US$300 million of stakeholder financing was destroyed. Although successful in the development of breakthrough technologies in the regenerative medicine arena and the building of a substantial portfolio of patents, the company never made a profit. In this case study, ATS’ business strategy, market and competitive environment will be discussed in the context of the company’s historical development. A number of important lessons from this case are discussed. From a management perspective the most critical lesson is the importance of effective financial planning and management of costs, and in particular R&D costs, including the significant costs associated with clinical trials. In addition, a clear strategic focus is extremely important due to the significant resources required in the development of a new therapy. From an investor’s perspective the lessons to be gath...
.This presentation will first address the physico-chemical properties of the weak polyelectrolytes, poly(vinyl amine) [PVAm] and poly(ethylene imine) [PEI] will be discussed; PVAm being a relatively new, versatile and poorly characterised...
more.This presentation will first address the physico-chemical properties of the weak polyelectrolytes, poly(vinyl amine) [PVAm] and poly(ethylene imine) [PEI] will be discussed; PVAm being a relatively new, versatile and poorly characterised material compared to the classic PEI. Molecular properties are of immense importance in the understanding of polymer performance in a wide range of applications. Details of the charging of both polymers’ will be given and a comparison will be drawn between the two polyelectrolytes. Charge density variation as a function of simple solution parameters for various molecular structures will be discussed and explained with reference to the Ising model 4 . The variation of polymer conformation as a function of solution conditions such as ionic strength and pH will also be discussed. Results on the non-equilibrium adsorption of the polymers onto various substrates at short polymer-substrate contact times will be given. The industrial application of the polyelectrolytes will be discussed with reference to specific examples, as will the optimisation of polymer performance via structural tailoring. Finally, potential applications of PVAm and PEI, as well as other polyelectrolytes, in nanotechnology will be
Surface area exclusion chromatography was used to investigate the adsorption and reconformation characteristics of hydrolyzed polyvinylamine molecules at silica/water interfaces employing radiolabeled polymers. The polymer solution was...
moreSurface area exclusion chromatography was used to investigate the adsorption and reconformation characteristics of hydrolyzed polyvinylamine molecules at silica/water interfaces employing radiolabeled polymers. The polymer solution was injected at the inlet of the column, whereas the polymer was successively adsorbed on the stacked glass-fiber filters constituting the stationary phase of the column. The filters and effluent samples collected at the outlet were individually analyzed for radioactivity content, which provided the adsorption histogram and the relative affinity of the various polymers. For saturated polymer layers, the relaxation process was demonstrated when the exceedingly adsorbed molecules desorbed. Modifications in the adsorption on the successive filters were thus converted into changes in the interfacial area of adsorbed molecules, taking into account the deviation from the plateau adsorption expected for nonrelaxing systems. Adsorption characteristics of nonrelaxed polymer layers were determined from the adsorption values determined before relaxation occurred. Adsorption and relaxation characteristics were determined to depend strongly on molecular weight and degree of hydrolysis of the polyvinylamine molecules. Half-hydrolyzed polymers had adsorption and relaxation characteristics close to those of the fully hydrolyzed polyvinylamine. Accordingly, adsorption isotherms on the cellulose/water interface were carried out to possibly extend the main conclusions of the study.
Surface area exclusion chromatography was used to investigate the reconformation of fully hydrolyzed polyvinylamine. The polymer is adsorbed on stacked glass fiber filters constituting the stationary phase while the polymer solution is...
moreSurface area exclusion chromatography was used to investigate the reconformation of fully hydrolyzed polyvinylamine. The polymer is adsorbed on stacked glass fiber filters constituting the stationary phase while the polymer solution is injected at the inlet of the chromatography column. From numerical simulation and experimental chromatograms of nonreconforming polyelectrolytes, the amount of polymer adsorbed per filter represented as a function of the filter position along the column (the histogram) was determined to be continuously decreasing and not to depend on the rate of elution. For polyvinylamine, the histograms are peaked and the height of the peak was determined to depend greatly on the rate of polymer supply to the column that was controlled by monitoring the polymer concentration and/or the rate of elution (mass-transfer-controlled adsorption). Modifications in the adsorption on the successive filters were converted into changes in the interfacial area of adsorbed molecules taking into account model histograms as well as experimental adsorption histograms of non reconforming systems. Macromolecule concentration in the mobile phase and contact time between solute and adsorbed molecules were determined to be the two parameters controlling the extent of polymer desorption. The unusual shape of the histogram thus was attributed to reconformation of the adsorbed polymer, which was stimulated by interfacial exchange between segments belonging to trains of adsorbed macromolecules and chain segments of solute ones.
Surface area exclusion chromatography was used to investigate the adsorption characteristics of the highly branched polyethyleneimine (PEI) molecule and of a related molecule resulting from the grafting of PEI with C12 to C22 alkyl...
moreSurface area exclusion chromatography was used to investigate the adsorption characteristics of the highly branched polyethyleneimine (PEI) molecule and of a related molecule resulting from the grafting of PEI with C12 to C22 alkyl chains. The interfacial relaxation and surface affinity of the two polymers was determined in homogeneous and heterogeneous layers. The presence of hydrophobic moieties within the branched morphology of the grafted PEI molecule was found to modify the adsorption histogram as compared to bare PEI and to lead to greater interfacial stability. The relaxation of the bare and grafted macromolecules proved to be of equal extent but to develop at different rates within homogeneous layers. In heterogeneous layers composed of the two polymers, the slower relaxation of the grafted macromolecules decreased the rate of relaxation of the bare molecules, while the faster relaxation of the bare molecules strongly increased the rate and extent of the relaxation of the grafted macromolecules. The same technique was then used to determine the mode of establishment of the layers. The polymer coating profiles on successive glass fiber filters of the chromatography column were found to depend on the sequence of injection of the two polymers. Simultaneous and sequential adsorption processes were analyzed on the basis of the random sequential adsorption of macromolecules.
Adsorption of fully hydrolyzed polyvinylamine on cellulose fibers in the short term was investigated by supplying the polymer to the fibers, first instantaneously by pouring the polymer solution into a jar containing the fiber dispersion...
moreAdsorption of fully hydrolyzed polyvinylamine on cellulose fibers in the short term was investigated by supplying the polymer to the fibers, first instantaneously by pouring the polymer solution into a jar containing the fiber dispersion (jar experiments) and second, at controlled rates (the reactor experiments). In the latter case, the rate of supply of polymer to the fiber dispersion confined in the reactor was monitored by setting the concentration of the solution being injected at a controlled rate. The concentration of the polymer solution exerts a paramount influence on the kinetics of adsorption and on the amount of polymer adsorbed at (or near) fiber surface saturation, while the rate of polymer supply only plays a minor role. The main observation is the emergence of two types of polymer layers corresponding to diffuse and dense layers. The former were characterized by adsorption layers of density smaller than 0.65 mg/g cellulose that are composed of adsorbed polymers having sustained extended flattening in the adsorbed state. The latter reach densities as high as 10 mg/g cellulose when the fiber surface is fully coated, thus indicating that reconformation is limited or even impeded at short terms. The threshold adsorption corresponds more or less to equilibrated layers, since the final coverage determined at adsorption equilibrium did not exceed 0.6 to 0.7 mg/g cellulose.