摘要:
A simplified and more efficient process is described for drying (and heat-treating) a lyotropic polybenzazole film in which the film is constrained in only the machine direction during drying (and heat-treating). The amount of stretching in the transverse direction the film undergoes prior to it being coagulated can be increased to compensate for the relaxation of the film during the drying process and the lack of stretching during the heat-treating process. Films made in this manner have acceptable finished properties.
摘要:
Mesogen containing biaxially oriented films are prepared from curable mixtures containing an epoxy resin and a curing agent therefor. Certain of the mesogen containing biaxially oriented films possess unique properties, such as a metallic like, highly reflective appearance. These films are useful in adhesives, coatings, laminates or composites and the like.
摘要:
Films containing polybenzazole polymer dissolved in a solvent can be mechanically stretched to provide biaxial orientation. The resulting dope film can be coagulated. The polymer film has improved properties in the direction in which stretching occurs.
摘要:
The invention is directed to a polypropylene resin, which is suitable for manufacturing an air quenched blown film. The resin has a melt flow rate of greater than 5 g/10 min, less than 2% xylene solubles, a pentad isotacticity of greater than 95%, an isotactic pentad/triad ratio of greater than 95%, a crystallinity of at least 65%, and a crystallization temperature of at least 127° C. The polypropylene resin contains from 500 ppm to 2500 ppm of a nucleator/clarifier additive. An quenched blown film made from resin exhibits a crystallization onset temperature of at least 116° C. and a crystallization half-life time of less 4.1 seconds or less when tested using fast DSC analysis with a scan rate of 200° C./minute.
摘要:
A structural panel for a vehicle or building contains a substrate and a layer of flame resistant polybenzazole polymer. If the substrate is heat resistant, the panel can serve as a fire barrier. If the substrate is not heat resistant, the polybenzazole layer can still serve to delay ignition and contain any volatile gases and molten polymer that forms when the panel is subjected to heat.
摘要:
A process for coagulating a polybenzazole film which includes contacting a lyotropic polybenzazole dope film that is constrained in at least two directions with a coagulant under conditions such that the polybenzazole polymer separates as a gelled moiety with the structure set such that further removal of solvent will result in no more than a 5% increase in the force necessary to constrain the film.
摘要:
The invention is a jacketed polymer optical fiber which comprises: an optical fiber which comprises a core formed from a light transmitting polymeric material having a first refractive index and a cladding formed from a polymeric material having a second refractive index which is lower than the first refractive index; and a jacket about the optical fiber wherein the jacket comprises a chlorinated polyethylene. The jacketed fibers of this invention have a higher service temperature than polyethylene jacketed fibers. The jacketed polymer optical waveguides of this invention are jacketed under conditions such that the optical properties of the polymer optical waveguide are not substantially degraded. The jacketed polymer optical waveguides have relatively low brittleness at use temperatures, good rigidity, and good solvent resistance. They also contain no material which tend to migrate into the polymer optical waveguide.
摘要:
A particulate cellulose derivative is obtained in a process of grinding and drying a moist cellulose derivative which comprises the steps of A) providing a cellulose derivative having a moisture content of from 60 to 95 percent, based on the total weight of the moist cellulose derivative, B) grinding and partially drying the moist cellulose derivative in a gas-swept impact mill; and C) contacting the ground and partially dried cellulose derivative with an additional amount of a drying gas outside the gas-swept impact mill. The obtained particulate cellulose derivative has a high untapped bulk density and a good flowability.
摘要:
In a process for producing a particulate polysaccharide derivative by dry-grinding a moist polysaccharide derivative, one or more of the properties selected from median diameter, median length, bulk density and dissolution rate is controlled by controlling the temperature of the polysaccharide derivative prior to thy-grinding. Advantageously one or more of the properties selected from median diameter, median length, bulk density and dissolution rate of the particles after thy-grinding is adjusted to a first value by a first temperature of the polysaccharide derivative prior to thy-grinding and is adjusted to a second value by a second temperature.
摘要:
The invention is directed to a polypropylene resin, which is suitable for manufacturing an air quenched blown film. The resin has a melt flow rate of greater than 5 g/10 min, less than 2% xylene solubles, a pentad isotacticity of greater than 95%, an isotactic pentad/triad ratio of greater than 95%, a crystallinity of at least 65%, and a crystallization temperature of at least 127° C. The polypropylene resin contains from 500 ppm to 2500 ppm of a nucleator/clarifier additive. An quenched blown film made from resin exhibits a crystallization onset temperature of at least 116° C. and a crystallization half-life time of less 4.1 seconds or less when tested using fast DSC analysis with a scan rate of 200° C./minute.