997 research outputs found

    From supramolecular architectures towards functional materials

    Get PDF

    Polyepoxides; formation and properties of their network structure

    Get PDF
    A discussion on epoxy resin network formation and properties with emphasis on study of the mechanisms of epoxide polymn. via phosphorescence and NMR spectroscopic methods. [on SciFinder (R)

    Photoinitiated cationic polymerization; a study to the polymerization and molecular mobility of polyepoxide networks using phosphorescence spectroscopy

    Get PDF
    The rate of network formation in the polymn. and crosslinking of 1-epoxyethyl-3,4-epoxycyclohexane, 1,4-butanediol diglycidyl ether, 3,4-epoxycyclohexylmethyl-3',4'-epoxy cyclohexane carboxylate, and cyclohexene oxide in the presence of di(4-tert-butylphenyl) iodonium hexafluoroarsenate photoinitiator was characterized by the increase in the intensity of fluorescence (lmax = 340 nm) and phosphorescence (lmax = 480) emissions. The half life of the triplet excited state was const. during polymn. which indicated that the increase in crosslink d. proceeded via an inhomogeneous pathway. The phosphorescence intensity and half life of all epoxy networks showed a discontinuity in their Arrhenius plots at .apprx.260 K due to the onset of quenching of the triplet excited state. The activation energy above the transition temp. was an indication of the increase in chain mobility with increasing temp. Dynamic thermomech. anal. of the networks established a correlation between the mech. properties and chain mobility

    Singlet oxygen oxygenation of enol ethers; the synthesis of optically active 1,2-dioxetanes. II

    Get PDF
    (+)-(Methoxymethylene)fenchane I (R = H, R1 = OMe) on singlet O oxidn. gave dioxetanes II and III, which on thermal decompn. underwent chemiluminescence in which (+)-fenchone was the only chemiluminescent species at lmax 420 nm. Photosensitized oxygenation of I (R = OMe, R1 = H) also gave 2 isomeric 1,2-dioxetanes. I were prepd. by Wittig methoxymethylenation of (+)-fenchone. Adamantanone (IV) on Wittig methoxymethylenation, followed by singlet O oxidn. gave dioxetane V, which on thermal decompn. gave only IV and HCO2Me and a bright blue chemiluminescence with lmax 420 nm and k1 2.96 * 10-3 s-1 at 79.9 Deg in decane. The prepn. of the dioxetanes allows the comparison of light- and chem. induced circular polarization of luminescence. [on SciFinder (R)

    Polymer compound

    Get PDF
    A Polymer compound comprising a polymer (a) that contains cyclic imidesgroups and a polymer (b) that contains monomer groups with a 2,4-diamino-1,3,5-triazine side group. According to the formula (see formula) whereby themole percentage ratio of the cyclic imides groups in the polymer compoundwith respect to the mole percentage of the monomer units with 2,4-diamino-1,3,5-triazine side group in the polymer compound is 0.1-10.0. Preferablypolymer (a) and/or polymer (b) contain styrene and/or alpha-methyl styreneas a co-monome

    Polyimide

    Get PDF
    The invention relates to a polyimide substantially built up from monomeric units of 3,3',4,4'-benzophenonetetracarboxylic dianhydride and monomeric units of a primary aliphatic diamine. The polyimide according to the invention is characterized in that the primary aliphatic diamine is substantially 1,4-diaminobutane. The thermal stability of the polyimide according to the invention has surprisingly been found to be very good. Owing to this very good thermal stability, the polyimides according to the invention can very well be processed at - relatively - high processing temperatures without any appreciable thermal degradation of the polyimide. As a result, the polyimides processing potential has increased considerably. Also, articles made of the polyimides according to the invention can be used at significantly higher temperatures. Said articles have very good mechanical properties. Articles containing a polyimide are suited for being used in the most diverse applications. Application within a large number of industries may be thought of, such as the electrical, electronic and automotive industries. In space travel, too, the interest in such polyimides is great
    corecore