Abstract: Melt-fusible polyimides based on pyromellitic dianhydride and at least one defined aromatic diamine are useful in making low-void composites and thermoplastic tapes, which can be fabricated into articles such as, for example, aircraft and autobody panels, printed circuit boards, etc. Some of these polyimides are melt-processible and can be fabricated by conventional procedures such as extrusion and injection molding.

Abstract: Terpolymers having 1,4-diketo functionalities and a carbonyl group concentration of about 5-20% of polymer weight can be conveniently cured by heating with an aromatic primary diamine or its precursor and a catalytic amount of an acid having a pKa of at most about 3. Cured polymers have good physical properties and are suitable in such applications as, for example hose, tubing, wire coatings, gaskets, and seals.

Abstract: A blend of an E/X/Y copolymer, where E is ethylene, X is a vinyl ester, and Y is carbon monoxide or sulfur dioxide, with a polymer of vinyl halide or vinylidene halide is foamed and cured by dispersing in the blend a blowing agent and sulfur or a sulfur-releasing agent and heating the blend containing those additives at 100.degree.-180.degree. C. for a sufficient time to produce curing and foaming. This process can be run either continuously or batchwise in conventional equipment under conventional conditions in the presence of air. Plasticizers and other materials which often interfere with peroxide cures can be present in the process of this invention. The foamed and cured products have excellent physical properties and ozone resistance.

Abstract: Perfluoro(2,2-dimethyl-1,3-dioxole) forms oligomers on standing in the presence of an ether. The preferred ethers are aliphatic and cycloaliphatic, especially tetrahydrofuran. Free radical generators, especially peroxydicarbonates, may be added to the reaction medium. The oligomers have a degree of polymerization of about 2-8. They are useful as lubricants, hydraulic fluids, heat transfer agents, and plasticizers, and as intermediates to oligomeric acid fluorides and acids, which acids are useful surfactants.

Abstract: Novel fluorodioxoles which may have Cl or F substituents in the 4 or 5 positions and have two F or CF.sub.3 substituents in the 2 position are useful monomers for the preparation of homopolymers and copolymers with tetrafluoroethylene and terpolymers with tetrafluoroethylene and vinylidene fluoride. The homopolymers are suitable for glazing materials, while copolymers are useful, among others, for corrosion-resistant seals, gaskets, and linings.

Abstract: Amorphous copolymers of perfluoro-2,2-dimethyl-1,3-dioxole with tetrafluoroethylene and, optionally, with another ethylenically unsaturated monomer, have high glass transition temperatures, e.g., 85.degree. C. or higher, low indices of refraction, and good physical properties which make them suitable for cladding optical fibers.

Abstract: Compatible blends of an ethylene/methacrylic or ethylene/acrylic acid dipolymer or a terpolymer with n-butyl or isobutyl acrylate with an ethylene/X/Y terpolymer, where X is vinyl acetate or an alkyl acrylate and Y is CO or SO.sub.2, with an elastomer, a blowing agent, and a curing agent can be readily formed into stiff foamed articles having very good physical properties, especially split tear and tensile strength. The foamed articles are useful, among others, in such applications as footwear, insulation, shock absorbance, floatation devices, seals and, gaskets.