摘要:
Prepare a closed-cell alkenyl aromatic polymer foam by an extrusion process using a blowing agent composition that contains at least 30 weight-percent of the chlorine-free hydrofluorocarbon blowing agent such that the foam has a density of 48 kilograms per cubic meter or less, contains more than 50 weight-percent styrene-acrylonitrile copolymer based on total polymer weight and at least eight weight-percent of a chlorine-free hydrofluorocarbon blowing agent that has a lower solubility in polystyrene than 1,1,2,2-tetrafluoroethane (HFC-134).
摘要:
Prepare a closed-cell alkenyl aromatic polymer foam by an extrusion process using a blowing agent composition that contains at least 30 weight-percent of the chlorine-free hydrofluorocarbon blowing agent such that the foam has a density of 48 kilograms per cubic meter or less, contains more than 50 weight-percent styrene-acrylonitrile copolymer based on total polymer weight and at least eight weight-percent of a chlorine-free hydrofluorocarbon blowing agent that has a lower solubility in polystyrene than 1,1,2,2-tetrafluoroethane (HFC-134).
摘要:
Alkenyl aromatic polymer foam comprising a polymer matrix containing one or more polymer and defining a plurality of cells having an average cell size wherein: (a) the alkenyl aromatic polymer foam has: —(i) an average cell size that is in a range of 0.02 and 5 millimeters; —(ii) a density of 64 kilograms per cubic meter or less; —(iii) an open cell content less than 30 percent; and —(iv) a cell size variation of 30% or less; and wherein the foam further comprises one or more fluorinated alkene blowing agent at a concentration of 0.03 moles or more and 0.3 moles or less per 100 grams of polymer foam.
摘要:
Alkenyl aromatic polymer foam comprising a polymer matrix containing one or more polymer and defining a plurality of cells having an average cell size wherein: (a) the alkenyl aromatic polymer foam has: —(i) an average cell size that is in a range of 0.02 and 5 millimeters; —(ii) a density of 64 kilograms per cubic meter or less; —(iii) an open cell content less than 30 percent; and—(iv) a cell size variation of 30% or less; and wherein the foam further comprises one or more fluorinated alkene blowing agent at a concentration of 0.03 moles or more and 0.3 moles or less per 100 grams of polymer foam.
摘要:
Provide a foamable polymer composition containing: (i) a thermoplastic polymer matrix and a blowing agent, (a) the thermoplastic polymer matrix containing a styrene-acrylonitrile copolymer having a weight-averaged molecular weight in a range of 90,000 to 150,000 and polymerized acrylonitrile concentration in a range of five to twenty weight-percent relative to total polymer matrix weight; and (ii) a blowing agent containing water, 1,1,1,2-tetrafluouroethane and at least one of difluoromethane and 1,1-dilluoroethane; (b) cooling the foamable polymer composition to a foaming temperature; and (c) extruding the foamable polymer composition and allowing the blowing agent to expand the foamable polymer composition into a polymeric foam having an average vertical cell size in a range of 0.5 millimeters to 1.8 millimeters and a density in a range of 24 to 40 kilograms per cubic meter and a Normalized Roughness Quotient of 3.5 or less in a Milled Surface Test.
摘要:
An electrically conductive article including a substrate and at least one electrically conductive layer disposed on the substrate. The conductive layer may include a thermoplastic resin and from about 1 to 30 weight percent of at least one conductive additive based on a total weight of the thermoplastic resin and the at least one conductive additive. The conductive article may have a surface resistance between 0.001 to 20Ω at a test distance of 2.54 cm (1 inch).
摘要:
Disclosed is an electrically conductive thermoplastic polymer composition comprising a thermoplastic polymer and a synergistic combination of metal fibers and metal-coated fibers, structures made therefrom, and a process to make said compositions and structures.
摘要:
A ceramic-metal composite that is tough and stiff has been prepared and is comprised of an inert ceramic (e.g., alumina) embedded and dispersed in a matrix comprised of a metal (e.g., aluminum), a reactive ceramic (e.g., boron carbide) and a reactive ceramic-metal reaction product (e.g., AlB2, Al4BC, Al3B48C2, AlB12, Al4C3, AlB24C4 or mixtures thereof) wherein grains of the inert ceramic have an average grain size greater than or equal to the average grain size of grains of the reactive ceramic. The ceramic-metal composite may be prepared by forming a mixture comprised of an inert ceramic powder (e.g., alumina) and a reactive ceramic powder (e.g., boron carbide), the inert ceramic powder having an average particle size equal to or greater than the average particle size of the reactive ceramic powder, forming the mixture into a porous body and consolidating the porous body in the presence of a metal (e.g., aluminum) to form the ceramic-metal composite.
摘要:
A method of forming a low level carbon high-density tungsten carbide-containing material includes sintering a preform which contains tungsten carbide powder and has a composition such that the resulting sintered material has at most 6.05 weight percent tungsten-bound carbon based on the total weight of tungsten and tungsten-bound carbon. This low level of carbon may be achieved by, prior to the sintering step, oxidizing the tungsten carbide powder sufficiently to achieve the desired substoichiometric carbon level in the sintered product or by adding a carbon-lowering material selected from the group consisting of tungsten, ditungsten carbide, and tungsten oxide. Optionally, other materials can be present in the preform such as carbon-getter metals and compounds thereof. The carbon-getter metals are those metals of which the carbides thereof are more thermodynamically stable than monotungsten carbide.
摘要:
An improved coating composition including a polymeric component and synthetic clay. The coating composition is particularly useful for coating a polymeric substrate, such as a styrenic polymeric substrate. One particular preferred application involves coating a closed cell foam extruded styrenic polymeric insulation panel with the coating composition, thereby realizing attractive barrier properties and optical characteristics from the coating.