Synthesis, characterization and curing studies of thermosetting epoxy resin with amines

A new hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) is prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with Epichlorohydrin by using benzyltrimethylammonium chloride as a catalyst. The resulting compound possesses both the oxirane ring and maleimide group. The curing reaction of these maleimidophenyl glycidylether epoxy compound (N-MPGE) with amines as curing agents such as ethylendiamine (EDA), diethylentriamine (DETA) and triethylenetetramine (TETA), aminoethylpiperazine (AEP) and isophoronediamine, IPDA), are studied. Incorporation of maleimide groups in the epichlorohydrin provides cyclic imide structure and high cross-linking density to the cured resins. The cured samples exhibited good thermal stability, excellent chemical (acid/alkali/solvent) and water absorption resistance. Morphological studies by the SEM technique further confirmed the phase homogeneity net work of the cured systems

Preparation and reactivity studies of maleimidophenyl glycidylether with amines

The hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) was prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with epichlorohydrin by using benzyltrimethylammonium chloride as a catalyst. The resulting compound possessed both the oxirane ring and maleimide group. The curing reaction of N-MPGE with amines as curing agents such as tetraethylenepentamine (TEPA), bishexamethylenetriamine (BHMT), 2-methyl pentamethylenediamine (2-MPMDA) and 2,2,4-trimethy diamines (2,2,4-TMDA) was studied. The cured samples exhibited good thermal stability and excellent chemical (acid/alkali/solvent) and water absorption resistance. Morphological studies by the SEM technique further confirmed the phase homogeneity network of the cured systems. © 2011 Chemical Society of Ethiopia

Ru(III)​-​catalyzed oxidation of some amines by chloramine-​T in hydrochloric acid medium: Mechanistic aspects and kinetic modeling

A review. The kinetics of oxidn. of five amines viz., ethylenediamine (EDA)​, diethylenetriamine (DETA)​, triethylenetetramine (TETA)​, aminoethylpiperazine (AEP) and isophoronediamine (IPDA) by sodium N-​chloro-​p-​toluenesulfonamide or chloramine-​T (CAT) in the presence of HCl and Ru(III) chloride was studied at 303 K. The five reactions followed identical kinetics and the exptl. rate law is rate = k[CAT]​0[amine]​x0[H+]​y[Ru(III)​]​z, where x, y and z are fractions. A variation of the ionic strength or dielec. const. of the medium and the addn. of halide ions and p-​toluenesulfonamide had no significant effect on the rate of the reaction. The solvent isotope effect has been studied in D2O medium. The activation parameters have been evaluated from the Arrhenius plots. Under comparable exptl. conditions, the rate of oxidn. of amines increases in the order: AEP > TETA > DETA > EDA > IPDA. An isokinetic relationship is obsd. with β = 377 K, indicating enthalpy as a controlling factor. Oxidn. products were identified. CH3C6H4SO2+NH2Cl of the oxidant has been postulated as the reactive oxidizing species. Further, the kinetics of Ru(III)​-​catalyzed oxidn. of these amines have been compared with unanalyzed reactions (in the absence of Ru(III) catalyst) and found that the catalyzed reactions are 2-​3-​fold faster. The catalytic const. (KC) was also calcd. for each amine at different temps. from the plots of log KC against 1​/T, values of activation parameters with respect to the catalyst have been evaluated. The obsd. results have also been explained by a plausible mechanism and the related rate law has been deduced

Synthesis of co(II), Ni(II) and Cu(II) complexes from schiff base ligand and reactivity studies with thermosetting epoxy resin

A hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) containing Co(II), Ni(II) and Cu(II) ions was prepared by curing N-MPGE and tetradentate Schiff base Co(II), Ni(II) and Cu(II) complexes. The curing polymerization reaction of N-MPGE with metal complexes as curing agents was studied. The cured samples were studied for thermal stability, chemical (acid/alkali/solvent) and water absorption resistance and homogeneity of the cured systems. The tetradentate Schiff base, 3-(Z)-2-piperazin-1-yl- ethylimino-1,3-dihydro indol-2-one was synthesized by the condensation of Isatin (Indole-2, 3-dione) with 1-(2-aminoethyl)piperazine (AEP). Its complexes with Co(II), Ni(II) and Cu(II) have been synthesized and characterized by microanalysis, conductivity, Uv-Visible, FT-IR, TGA and magnetic susceptibility measurements. The spectral data revealed that the ligand acts as a neutral tetradentate Schiff base and coordinating through the azomethine nitrogen, two piperazine nitrogen atoms and carbonyl oxygen

Synthesis and characterization of Schiff base metal complexes and reactivity studies with maleimide epoxy resin

A novel maleimide epoxy contg. Co(II)​, Ni(II)​, and Cu(II) ions have been synthesized by curing a maleimide epoxy resin (MIEB-​13) with Co(II)​, Ni(II)​, and Cu(II) complexes of a macrocyclic bis-​hydrazone Schiff base. The Schiff base was synthesized by reacting terephthaloyl dihydrazide with 2,​6-​diformyl-​4-​methylphenol. The Schiff base and its Co(II)​, Ni(II)​, and Cu(II) complexes have been characterized by elemental analyses, spectral (IR, 1H NMR, UV-​vis., FAB mass, ESR)​, thermal, and magnetic data. The curing reaction of the epoxy resin was carried out with the metal complex crosslinking agents. The stability of the cured samples was studied by thermogravimetric analyses; the products have excellent chem. (acid​/alkali​/solvent) and water absorption resistance. Further, SEM and DSC techniques confirmed the phase homogeneity of the cured systems

Synthesis, spectral characterization and in vitro microbiological evaluation of novel glyoxal, biacetyl and benzil bis-hydrazone macrocyclic Schiff bases and their Co(II), Ni(II) and Cu(II) complexes

A series of binuclear Co(II), Ni(II) and Cu(II) complexes were synthesized by the template condensation of glyoxal, biacetyl or benzil bis-hydrazide, 2,6-diformyl-4-methylphenol and Co(II), Ni(II) or Cu(II) chloride in a 2:2:2 M ratio in ethanol. These 22-membered macrocyclic complexes were characterized by elemental analyses, magnetic, molar conductance, spectral, thermal and fluorescence studies. Elemental analyses suggest the complexes have a 2:1 stoichiometry of the type M2LX2·nH2O and Ni2LX22H2O·nH2O (where M = Co(II) and Cu(II); L = H2L1, H2L 2 and H2L3; X = Cl; n = 2). From the spectroscopic and magnetic studies, it has been concluded that the Co(II) and Cu(II) complexes display a five coordinated square pyramidal geometry and the Ni(II) complexes have a six coordinated octahedral geometry. The Schiff bases and their metal complexes have also been screened for their antibacterial and antifungal activities by the MIC method. © 2011 Elsevier Ltd. All rights reserved

Synthesis, spectral characterization, in-vitro microbiological evaluation and cytotoxic activities of novel macrocyclic bis hydrazone

A macrocyclic hydrazone Schiff base was synthesized by reacting 1,4-dicarbonyl phenyl dihydrazide with 2,6-diformyl-4-methyl phenol and a series of metal complexes with this new Schiff base were synthesized by reaction with Co(II), Ni(II) and Cu(II) metal salts. The Schiff base and its complexes have been characterized by elemental analyses, IR, 1H NMR, UV-vis, FAB mass, ESR spectra, fluorescence, thermal, magnetic and molar conductance data. The analytical data reveal that the Co(II), Ni(II) and Cu(II) complexes possess 2:1 metal-ligand ratios. All the complexes are non-electrolytes in DMF and DMSO due to their low molar conductance values. Infrared spectral data suggest that the hydrazone Schiff base behaves as a hexadentate ligand with NON NON donor sequence towards the metal ions. The ESR spectral data shows that the metal-ligand bond has considerable covalent character. The electrochemical behavior of the copper(II) complex was investigated by cyclic voltammetry. The Schiff base and its complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Shigella dysentery, Micrococcus, Bacillus subtilis, Bacillus cereus and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Penicillium and Candida albicans) by MIC method. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties. © 2009 Elsevier Masson SAS. All rights reserved