摘要:
A contact lens for correction of astigmatism is formed from a single polymeric or copolymeric material. The lens has a central optical zone of greater rigidity than a surrounding non-optical zone. The rigidity of the central optical zone is sufficient for it to retain an astigmatism-correcting shape when worn on an eye, while the surrounding non-optical zone conforms to the shape of the eye.
摘要:
The surfaces of shaped articles prepared from a polymer derived from monomer comprising an acrylate and/or methacrylate can be improved by treating the article with hot water, with an aqueous alkali solution or with an aqueous acid solution. Stains can easily be removed from the surfaces of articles treated in this way and the articles are hydrophilic and have excellent water wettability. The invention is particularly valuable for the treatment of contact lenses.
摘要:
The wettability of polyolefin or polyester film for use as a heat exchange membrane, e.g. tubes or sheets, in a heat exchanger is increased, generally to a surface tension reading in excess of 70 dynes/cm, by treating the surface of the film with a strong oxidising agent, particularly gaseous sulphur trioxide. The heat transfer coefficient is thereby improved. Tubes of such plastics material having a treated outer surface and an untreated inner surface are particularly useful for exchanging heat between a liquid flowing over the outer surface and a gas or vapour condensing within the tube.
摘要:
The electrically conducting polymer includes poly (N-alkyl 3', 3 carbazolyl) at least a portion of which is doped with a compatible charge transfer acceptor to provide p-type electrical conductivity, and in which the alkyl group is of ethyl or methyl or a combination thereof. The method includes the steps of preparing a first solution comprising a Grignard reagent of at least a portion of a quantity of N-alkyl -3', 3 dibromocarbazole monomerto be polymerized, preparing a second solution of the remainder of the monomer in a suitable solvent; polymerizing a mixture of said first and said second solution in the presence of a suitable initiator for sufficient time to produce a high molecular weight polymer; recovering said polymer; and doping said polymer with a compatible charge transfer acceptor.
摘要:
Molded articles formed of polystyrene or other polymers containing an aromatic moiety can be derivatized on the surface of the article by subjecting the molded article to a chemical reaction wherein the reaction media utilizes tetramethylsulfone as the reactant solvent and a suitable substituent group which is substituted on to the aromatic moiety of the polystyrene or other polymer by electrophilic substitution. By choosing the substituent group to further include a leaving group, further substitution of the primary substituent can be effected normally by nucleophilic substitution reaction. In this way, biologically important molecules can be attached to a polystyrene or other aromatic containing polymer without effecting certain properties of the molded article such as its optical or spectroscopic clarity.
摘要:
Zur Oberflächenmodifikation von natürlichen oder syn thetischen makromolekularen Substraten werden organische Verbindungen verwendet, die einerseits hydrophile, hydro phobe, oleophobe, ionische und/oder vernetzbare Gruppen, andererseits zu Nitren oder Carben überführbare Gruppen, zB Azid- oder Diazogruppen aufweisen. Diese Verbindungen werden als Mono- oder Oligolayer aus der Lösung auf die zu modifizierende Oberfläche gebracht und anschließend pho tochemisch aktiviert. Dabei sind solche Bedingungen vorteil haft, welche eine Orientierung des Moleküls mit der Azid- bzw. Diazogruppe zur Substratoberfläche hin bewirken. Die weiteren vernetzbaren Gruppen können zur Querbenetzung der aufgebrachten Schichten dienen.
摘要:
The present application relates to enclosure members consisting essentially of solid, non-aromatic polymers that have a linear carbon to carbon backbone structure and having a plurality of free hydrogen atoms attached to the carbon atoms with a permeability to wet solvents and fuels of less than 1/7, optionally less than 1/40 of the permeability of untreated enclosure members having a tickness of 1 mm. Said low permeability is due to the presence of a layer of an iron phenanthroline complex on at least the inner surface of said enclosure members, having a portion of the hydrogen atoms replaced by sulphonic acid or sulphonate groups.
摘要:
Die Erfindung betrifft ein Verfahren zur Herstellung von mindestens größtenteils wasserunlöslichen Acrylpolymeren mit hoher Wasserquellfähigkeit durch Umsetzung von Polyacrylnitril oder Copolymeren auf der Basis von Acrylnitril mit wäßrig-alkalischen Lösungen, die gegebenenfalls ein mit Wasser mischbares Lösemittel enthalten. Das Polymere wird in diesem Verfahren bei einer Temperatur von mehr als 100°C umgesetzt, insbesondere mit wäßrig-alkalischen, einen ein- oder mehrwertigen, aliphatischen oder cycloaliphatischen Alkohol eines Siedepunktes von ≧ 110°C enthaltenden Lösungen. In einer anderen bevorzugten Variante des Verfahrens wird das Polymere unter Überdruck umgesetzt. Die derart hergestellten Acrylpolymeren können beispielsweise zur Aufnahme und/oder Zurückhaltung von wäßrigen Flüssigkeiten oder von Feuchte verwendert werden.