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Pyrenesulfonamide-labeled model associative polymers were prepared via copolymerization of acrylamide with 0.5 mol% N-[(1-pyrenylsulfonamido)ethyl]acrylamide. The microheterogeneous surfactant technique yields a copolymer which exhibits intermolecular associative behaviour in aqueous media. Conversely, light scattering studies indicate the compact nature of the copolymer prepared by the homogeneous solution technique. Intramolecular hydrophobic associations dominate rheological behavior

Copolymers of acrylamide containing less than 0.5 mol% N-[(1-pyrenylsulfonamido)ethyl]acrylamide were studied in aqueous solution. The copolymer prepared by a surfactant technique was shown to possess some inherent blockiness or short runs of the pyrenesulfonamide label in dilute solution. Intermolecular associations were observed above a critical concentration. The copolymer prepared by solution polymerization showed random incorporation of the pyrenesulfonamide comonomer and no intermolecular association tendency over the concentration range studied

A study has been conducted to determine the effects of added elastomers on the film properties of a linear aromatic polyimide. Polyamic acids have been prepared via reaction of BTDA (3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride) with ODA (4,4′-oxydianiline) and various ATBN (aromatic amineterminated butadiene acrylonitrile) elastomers. Films were prepared and thermally converted to the corresponding polyimides. Optimum cure conditions for BTDA + ODA/ATBN films were evaluated. The effect of elastomer concentration on BTDA + ODA thermal properties, density, tensile properties, morphology and tear resistance were evaluated. Variation of the acrylonitrile content of the ATBN elastomer in BTDA + ODA was performed and properties evaluated. Incorporation of ATBN into BTDA + ODA caused a decrease in the glass transition temperature, thermal stability, tensile strength and modulus of films. Increases of film tear resistance were observed for several formulations of ATBN in the BTDA + ODA polyimide.

The hydrolytic controlled release behavior of copolymers with pendent esters of the plant growth regulators naphthaleneacetic acid and indoleacetic acid have been studied utilizing reversed phase liquid chromatography with ultraviolet spectrometric detection. The release profiles for copolymers of acrylamide (AM) with 2-(1-napthylacetyl) ethyl acrylate (NAEA), 4-(1-napthylacetyl) butyl acrylate (NABA), 2-(1-napthylacetyl) ethyl acrylate (NAEMA), and 2-(indole-3-acetyl) ethyl acrylate (IAEA) were shown to depend upon the nature of the auxin monomer structure and its composition, molecular weight, and copolymer microstructure. Increasing the mean sequence lengths of the hydrophilic sections of the copolymers was shown quantitatively to result in higher rates of hydrolytic release.

Films ayant une resistivite de 10 5 -10 8 Ω/cani et une stabilite thermique superieure a 500°C. La couche d'oxyde d'etain sur des films durcis a l'air est photoactive

A series of studies evaluating the effects of added elastomers on the properties of a high-temperature addition polyimide adhesive is reviewed. First, thermoset polyimides containing various butadiene/acrylonitrile and silicone elastomers were synthesized either as physical polyblends or by chemically reacting the elastomers directly onto the polymer backbone. The modified adhesive resins were characterized for thermomechanical properties, fracture toughness and adhesive strength. A second series of elastomer-containing polyimides was also prepared in order to study the effects of the elastomer chain length on polymer properties. Aromatic amine-terminated silicone rubbers with repeat units varying from n=10 to 105 were reacted onto the polyimide backbone, and the resulting polymers were characterized for their adhesive properties.