Synthesis of waterborne epoxy resin with diethanolamine-assisted succinimide for improving the strand integrity of polyimide filament

A water-soluble epoxy resin emulsion was synthesized by diethanolamine-assisted succinimide modified epoxy resin (DSEP) and used to reinforce the strand integrity of polyimide filament (PI). FTIR, XPS, and 1H NMR provide an evidence for the succinimide (SI) and diethanolamine (DEA) bonded onto the epoxy resin (EP) structure in the form of C-N-C. The DSEP emulsion shows high storage and dilution stability, with its particle size distribution and PDI of 118∼232 nm and 0.106∼0.638, respectively. Compared with DEA modified EP, DSEP exhibits better strand integrity for PI filament. The breaking strength of PI filament infiltrated by DSEP can reach 2.59 GPa, which is increased by 47.04% than that of PI filament, and is close to that of commercially available water-soluble polyimide resin (2.63 GPa). In addition, the fracture microstructure of PI filament further confirms that DSEP significantly reinforces the aggregation of PI filament. Importantly, there is no wire splitting phenomenon of DSEP reinforced PI filament after more than 200 times of friction. These benefit from the similar material groups of imide ring and benzene ring between DSEP and PI filament structure, as well as the strong hydrogen bonding interaction between them, as further confirmed by FTIR and SEM analysis.

Selective Aerobic Oxidation of P-Methoxytoluene by Co(II)-Promoted NHPI Incorporated into Cross-Linked Copolymer Structure

A wide series of copolymer materials with various contents of 4-vinyl-diisopropyl-phtalate ester (10–90 mol%), divinylbenzene (1–11 mol%) and styrene, as monomers, were obtained by radical copolymerization. In the last steps of the synthesis, diisopropyl ester functionalities were converted into the form of N-hydroxyphthalimide (NHPI) rings. The obtained materials with the NHPI groups immobilized in the copolymer structure were studied by various physicochemical techniques, including FT-IR, UV-Vis-DR, XPS, elemental analysis, and tested as catalysts in aerobic oxidation of p-methoxytoluene in the presence of Co(II) acetate co-catalyst. Conversion of the aromatic substrate was correlated with the NHPI content and cross-linking degree. The best catalytic performance (conversions higher than 23%) was achieved for the copolymer catalysts containing 60% and 30% of 4-vinyl-diisopropyl-phtalate ester. At too high concentrations of NHPI and DVB, some of the NHPI groups were transformed into inactive (C=O)-N=O species or not available due to embedding inside the copolymer structure. The mechanism of the process involving both NHPI centers, forming phthalimide N-oxyl (PINO) radicals, and Co(II) cations was discussed. Stability of the developed catalysts was also tested. The opening of imide rings took place during the catalytic process, resulting in the formation of carboxyl groups and the release of hydroxylamine molecules. The deactivated catalyst could be easily regenerated by repeating two last steps of closing imide ring.

Microwave assested synthesis of phthalimide amino derivatives with their antioxidant potential

Imide is the configuration of amide in which the nitrogen atom is affix to two carbonyl group. Imide mention to any compound which carry the divalent radical. Phthalimide possess a structural feature CHNO and an imide ring which help them to be biologically active and pharmaceutically useful.Phthalimides have served as starting materials and intermediates for the synthesis of many types of alkaloids and pharmacophores.In view of broad biological activity of phthalimide, we herein plan to synthesize a series of new phthalimide derivatives by incorporating new pharmacophores at various positions with the hope to get therapeutically active compounds. The aim the study is to synthesize phthalimide derivatives by using microwave assisted synthesis method and compare the activity of the synthesized molecules. Thus, the current communication employed the technology gracefully for the synthesis, identification and characterization of some novel derivatives by the reaction of Phthalic anhydride with urea, glycine, aniline, sulphanilic acid to yield various Phthalimide derivatives using domestic microwave by getting percentage yield 70.7%, 76.65%, 80.21% and 73.78% of synthesized compound BBBand Brespectively. The compound B(92.86%) showed higher percentage practical yield. All synthesized compound(s) were subjected to melting point determination, TLC analysis, column chromatography (for purification), H-NMR and Mass Spectrometry. All synthesized derivatives were subjected for DDPH scavenging activity, in which compound Bwas found to have high anti-oxidant potential (69.56%) when ascorbic acid was taken as standard. All the chemicals used were of highly pure and procured from Central Drug House (New Delhi).

Heat of Decomposition and Fire Retardant Behavior of Polyimide-Graphene Nanocomposites

Polyimide is a high-performance engineering polymer with outstanding thermomechanical properties. Because of its inherent fire-retardant properties, polyimide nanocomposite is an excellent material for packaging electronic devices, and it is an attractive electrode material for batteries and supercapacitors. The fire-retardant behavior of polyimide can be remarkably improved when polyimide is reinforced with multilayered graphene sheets. Differential scanning calorimetry and thermogravimetric analysis were used to study the heat of decomposition and gravimetric decomposition rate, respectively, of polyimide-graphene nanocomposites. Polyimide/graphene nanocomposites containing 10, 20, 30, 40, and 50 wt.% of multilayered graphene sheets were heated at a rate of 10 and 30 °C/min in air and in nitrogen atmosphere, respectively. The rate of mass loss was found to remarkably decrease by up to 198% for nanocomposites containing 50 wt.% of graphene. The enthalpy change resulting from the decomposition of the imide ring was found to decrease by 1166% in nitrogen atmosphere, indicating the outstanding heat-shielding properties of multilayered graphene sheets due to their high thermal conductivity. Graphene sheets are believed to form a continuous carbonaceous char layer that protects the imide ring against decomposition, hence decreasing initial mass loss. The enthalpy changes due to combustion, obtained from differential scanning calorimetry, were used to calculate the theoretical heat release rates, a major parameter in the determination of flammability of polymers. The heat release rate decreased by 62% for composites containing 10 wt.% of graphene compared to the neat polyimide matrix. Polyimide has a relatively lower heat of combustion as compared with graphene. However, graphene significantly decreases the mass loss rates of polyimide. The combined interaction of graphene and polyimide led to an overall decrease in the heat release rate. It is noted that both mass loss rate and heat of combustion are important factors that contribute to the rate of heat released.

Syntheses and crystal structures of the anhydride 4-oxatetracyclo[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione and the related imide 4-(4-bromophenyl)-4-azatetracyclo[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione

The syntheses and crystal structures of the two title compounds, C11H10O3 (I) and C17H14BrNO2 (II), both containing the bicyclo[2.2.2]octene ring system, are reported here [the structure of I has been reported previously: White & Goh (2014). Private Communication (refcode HOKRIK). CCDC, Cambridge, England]. The bond lengths and angles of the bicyclo[2.2.2]octene ring system are similar for both structures. The imide functional group of II features carbonyl C=O bond lengths of 1.209 (2) and 1.210 (2) Å, with C—N bond lengths of 1.393 (2) and 1.397 (2) Å. The five-membered imide ring is nearly planar, and it is positioned exo relative to the alkene bridgehead carbon atoms of the bicyclo[2.2.2]octene ring system. Non-covalent interactions present in the crystal structure of II include a number of C—H...O interactions. The extended structure of II also features C—H...O hydrogen bonds as well as C—H...π and lone pair–π interactions, which combine together to create supramolecular sheets.

Synthesis and characterization of poly(amide-imide)s derived from a new ortho-functional unsymmetrical dicarboxylic acid

Herein, we report a new diacid monomer containing an imide ring and a methoxy pendant group, 3-trimellitimido-4-methoxybenzoic acid TMBA, for the preparation of poly(amide-imide)s.

Crystal structure ofN-[2-(cyclohexylsulfanyl)ethyl]quinolinic acid imide

The title compound, C15H18N2O2S {systematic name: 6-[2-(cyclohexylsulfanyl)ethyl]-5H-pyrrolo[3,4-b]pyridine-5,7(6H)-dione}, was obtained from the reaction of pyridine-2,3-dicarboxylic anhydride (synonym: quinolinic anhydride) with 2-(cyclohexylsulfanyl)ethylamine. The dihedral angle between the mean plane of the cyclohexyl ring and the quinolinic acid imide ring is 25.43 (11)°. In the crystal, each molecule forms two C—H...O hydrogen bonds and one weak C—O...π [O...ring centroid = 3.255 (2) Å] interaction with neighbouring molecules to generate a ladder structure along theb-axis direction. The ladders are linked by weak C—O...π [O...ring centroid = 3.330 (2) Å] interactions, resulting in sheets extending parallel to theabplane. The molecular structure is broadly consistent with theoretical calculations performed by density functional theory (DFT).