Abstract:
Provided is a composite comprising a polymer and a plurality of surface-modified hexagonal boron nitride particles dispersed therewithin. Suitable polymers include polyimide and epoxy. A process is also provided. The surface modified hexagonal boron nitride particles comprise surface-bonded substituted phenyl radicals
Abstract:
Epoxy compositions exhibiting low viscosity in the uncured state and low coefficient of thermal expansion in the cured state are provided. Also provided are processes for making the epoxy compositions. The low dielectric constant compositions are well-suited for use in multi-layer printed circuit boards. The desired properties are achieved by employment of a bimodal distribution of nano-scale fillers in the epoxy compositions.
Abstract:
Cross-linked polymers comprising an anhydride or partially hydrolyzed anhydride functionalized polymer having oligomeric polyamic acid cross-links are provided. In solution, a polymer of the invention forms a formable gel. The formable gel is useful for forming shaped articles that are useful for electronics applications.
Abstract:
Disclosed are compositions prepared by free-radical-driven grafting onto hydrocarbons or hydrocarbon ethers of olefinically unsaturated fluorocarbons containing sulfonyl fluoride, fluorosulfonate, fluorosulfonimide, or fluorosulfonyl methide groups, wherein the grafting step is followed by a hydrolysis step in the case of sulfonyl fluoride.
Abstract:
Provided according to the invention are cross-linked polymers comprising an anhydride or partially hydrolyzed anhydride functionalized polymer having oligomeric polyimide cross-links, providing a polymeric composite on a molecular scale, and shaped articles made therefrom. In some embodiments the shaped articles are particularly well suited for electronics applications. The shaped articles are characterized by low CTE (coefficient of thermal expansion), low dielectric constant (Dk), low dissipation factor (Df), high strength, high modulus and high toughness.
Abstract:
Cross-linked polymers comprising an anhydride or partially hydrolyzed anhydride functionalized polymer having oligomeric polyamic acid cross-links are provided. In solution, a polymer of the invention forms a formable gel. The formable gel is useful for forming shaped articles that are useful for electronics applications.
Abstract:
Disclosed are fiber reinforced composite substrates comprising a polymeric matrix and one or more woven or non-woven para-aramid or fiberglass fabrics, sheets, or papers, said polymeric matrix consisting essentially of one or more cross-linked copolymers of monovinyl aromatic hydrocarbons and conjugated dienes useful for printed circuit boards and cards suitable for use in high frequency circuits.
Abstract:
The present invention relates to an apparatus and a process for a half-cell structure to make a hexagonal-cell honeycomb core. The structure has a plurality of peaks and valleys and a diagonal surface between each consecutive peak and valley. The apparatus comprises a stack holder for stacking the structure so that as one sheet is placed on top of a stack comprising at least one sheet, the peaks of one sheet contact the peaks of an adjacent sheet. The apparatus also comprises an air blower disposed beneath the top of the stack for reducing the air pressure surrounding the stack to a pressure below the air pressure on the top of the stack, thereby pressing the layers together to form the core. The present invention also relates to a transfer head and a process for holding a half-cell structure. The transfer head comprises a plurality of support bars for supporting the half-cell structure and at least one space formed between each support bar, where the width of each space is about the distance between adjacent valleys of the structure, and the depth of the space is greater than the height of the peaks.
Abstract:
The present invention relates to an apparatus and a process for applying at least one adhesive component to a honeycomb half-cell structure. The half-cell structure has a plurality of peaks and valleys on each side thereof and a diagonal surface between each consecutive peak and valley. The apparatus comprises a first and second back-up roll and a first and second gravure roll. The first and second gravure rolls are disposed in a bath of a first adhesive component and a second adhesive component, respectively. Each of the first and second back-up rolls includes a plurality of spaced bars. The peaks of the half-cell structure face away from the bars of each respective back-up roll, and the peaks on the other side of the half-cell structure contact each respective first and second gravure roll, so that the first adhesive component contacts the peaks on the one side and the second adhesive component contacts the peaks to apply the first and second adhesive components to the half-cell structure.
Abstract:
Quaternary ammonium bicarbonates are suitable for use as catalysts in curable epoxy compositions. The curable compositions prepared therewith are used to prepare coated substrates, and to produce conformally sealed printed wiring boards and flexible circuits. Methods for preparation and curing are also provided. Of particular utility are compositions comprising benzytrimethyl ammonium bicarbonate. The curable composition is coated onto a first film or sheet, including a polyimide film or sheet. The coated sheet is then contacted to the surface of second film or sheet, where preferably there are discrete metallic conductive pathways disposed thereupon.