Bidhan Samanta

Modification of cured epoxy with amine functional chloroaniline formaldehyde condensate

Purpose – The purpose of this paper is to evaluate the improvement of mechanical and thermal properties of cured epoxy modified with amine functional chloroaniline formaldehyde condensate (AFCFC) and to determine the optimum level of modification.Design/methodology/approach – To evaluate toughening, different compositions were made by adding various concentration of AFCFC to epoxy. The impact, adhesive, tensile and flexural strengths of the modified and the unmodified epoxy were characterised by dynamic mechanical analysis. Thermogravimetric properties of modified epoxy were also reported.Findings – The modification of epoxy resin using AFCFC showed significant enhancement of mechanical strength over unmodified epoxy. The reason behind this is that, in the initial stage of curing, the AFCFC are miscible with the epoxy and form a homogeneous solution. This homogeneity promotes the chemical reaction and network formation. During the curing process, as the molecular weight increases, the component separates ...

Effect of modifier and filler concentration on properties of epoxy‐red mud waste composite

Purpose – The purpose of this paper is to evaluate the concentration effect of liquid amine terminated poly (ethylene glycol) benzoate (ATPEGB) modifiers and red mud waste filler on mechanical and thermal properties of cured epoxy along with the optimum result of modified epoxy.Design/methodology/approach – For effective toughening, different compositions are made by adding various concentration of ATPEGB to epoxy. The concentration of 2, 5 and 10 parts per 100 parts of epoxy resin of aluminium silicate‐based pristine red mud waste is incorporated into each modified epoxy matrix. These filled modified matrixes are cured with ambient temperature curing agent triethylene tetramine and are evaluated with respect to their impact, tensile and flexural strengths. The morphology is analysed by scanning electron microscopy and dynamic mechanical analysis. The thermal stability by thermogravimetric analysis is also reported.Findings – The modification of epoxy resin using ATPEGB and filler shows significant enhanc...

Amine-terminated poly(ethylene glycol) benzoate (ATPEGB)-modified epoxy: mechanical and thermal properties

Amine-terminated poly(ethylene glycol) benzoate (ATPEGB), synthesized from the esterification reaction of poly(ethylene glycol) (PEG) with 4-amino benzoic acid, was used to modify the toughness of bisphenol-A diglycidyl ether epoxy resin (DGEBA) cured with room temperature curing agent, triethylene tetramine. ATPEGB was characterized by FT-IR and H-NMR spectroscopies, viscosity measurements, solubility parameter calculation and molecular weight determination with gel-permeation chromatography (GPC). The modified epoxy network was evaluated for its impact, adhesive, tensile, flexural and thermal properties. Improvement in mechanical properties depends upon the concentration of the ATPEGB modifier. The optimum properties were obtained at 12.5 phr (parts per hundred parts of resin) concentration of the modifier. The ATPEGB modified cured epoxy was thermally stable up to 315°C. The morphology of cured epoxy was also analyzed by scanning electron microscopy (SEM) investigation of fracture surfaces.

Quantifying conventional C–H⋯π(aryl) and unconventional C–H⋯π(chelate) interactions in dinuclear Cu(II) complexes: experimental observations, Hirshfeld surface and theoretical DFT study

Two novel Cu(II) complexes, [Cu2L2(μ1.1-N3)2] (1) and [Cu2L2(μ1.1-CH3COO−)2]·2H2O (2), have been synthesized using a tridentate NNO donor Schiff base ligand, 2-[(piperidin-2-ylmethylimino)-methyl]-phenol (HL) and azide or acetate as the co-ligand. Both the structures exhibit elongated (4 + 1) square pyramidal geometries and are centrosymmetric dimers, in which the metal centers are connected by the double μ1.1-azido and acetate bridges. Both complexes exhibit unconventional C–H⋯π(chelate) interaction along with conventional C–H⋯π(aryl) supramolecular interactions in the solid-state assembly. A detailed analysis of Hirshfeld surfaces and fingerprint plots elegantly quantifies the interactions within the crystal structures, revealing significant similarities and differences in the interactions experienced by the complexes. The intricate combinations of C–H⋯π(chelate) and C–H⋯π(aryl) interactions are fully described along with the computational studies. The binding energies associated with the noncovalent interactions observed in the crystal structures and the interplay between them have been calculated using theoretical DFT calculations. Moreover, the interactions have been characterized by using both Baders theory of “atoms-in-molecules” and the noncovalent interaction plot (NCI plot).

Synthesis, structure, and biological properties of a Co(II) complex with tridentate Schiff base ligand

Abstract A new Co(II) complex of general formula [Co(L)2] has been synthesized from a NNO tridentate Schiff base ligand, 2-[(piperidin-2-ylmethylimino)-methyl]-phenol (L). The title complex is characterized by elemental, spectroscopic, antibacterial, and single crystal X-ray structural studies. X-Ray crystallography reveals that the complex shows a distorted octahedral geometry around the Co(II) ion. The complex was tested against several bacteria and shows good antibacterial activities against almost all of the bacteria. The interactions of the title complex with calf thymus deoxyribonucleic acid (CT-DNA) have been investigated by electronic absorption and fluorescence spectroscopy, showing that the complex interacts with CT-DNA via partial intercalation. Thermogravimetric analysis (TGA) of the complex has also been reported and the result shows that the complex is thermally stable up to 134 °C.

A square pyramidal copper(II) complex of a Schiff base ligand: synthesis, crystal structure, antibacterial and DNA interaction studies

A mononuclear Cu(II) complex [Cu(L)Cl2] has been synthesized from a tridentate Schiff base ligand, piperidin-2-ylmethyl-pyridin-2-ylmethylene-amine (L). The single-crystal X-ray structure of the complex shows a square pyramidal geometry. The complex was tested against several bacteria and showed good antibacterial activities against almost all of the bacteria. The interactions of the title complex with calf thymus DNA (CT-DNA) have been investigated by electronic absorption and fluorescence spectroscopy, showing that the complex interacts with CT-DNA via partial intercalation.

Synthesis, characterisation, curing reaction of aniline acetaldehyde condensate with epoxy resin

Purpose – The purpose of this paper is to find a new curing agent for diglycidyl ether of bisphenol A (DGEBA) resin and to check effectiveness of this new curing agent to obtain toughness and chemical resistance of cured epoxy.Design/methodology/approach – For this purpose, an investigation was carried out to synthesise, characterise and to study curing reaction of amine functional aniline acetaldehyde condensate (AFAAC) with DGEBA resin. AFAAC was first synthesised from the reaction of aniline and acetaldehyde in acid medium and characterised by FT‐IR, 1H‐NMR spectroscopic analyses, elemental analysis, concentration of primary and secondary amine analysis. Then equimolecular mixture of AFAAC and DGEBA was subjected to curing reaction and the reaction was followed by differential scanning calorimetry (DSC) analysis. The kinetic studies of this curing reaction, mechanical properties, dynamic mechanical analysis and thermogravimetric analysis (TGA) of cured epoxy were also reported.Findings – The DSC analys...

Amine functional aniline furfuraldehyde condensate cured epoxy resin

Purpose – The purpose of this paper is to investigate the curing efficiency of amine functional aniline furfuraldehyde condensate (AFAFFC) for diglycidyl ether of bisphenol A (DGEBA) resin to achieve toughness, chemical resistance, etc.Design/methodology/approach – To study curing reaction, the curing agent AFAFFC is synthesised first from the reaction of aniline and furfuraldehyde in acid medium and characterised by Fourier transform infrared spectroscopic analysis, elemental analysis, concentration of primary and secondary amine analysis. Then, equimolecular mixture of AFAFFC and DGEBA is subjected to curing reaction and the reaction is followed by differential scanning calorimetry (DSC) analysis. The kinetic studies of this curing reaction, mechanical properties, dynamic mechanical analysis and thermogravimetric analysis (TGA) of cured epoxy are also reported.Findings – The DSC analysis shows the complete exotherms of effective curing reaction indicating the efficiency of AFAFFC as curing agent for DGE...

Curing study and evaluation of epoxy resin with amine functional chloroaniline acetaldehyde condensate

Purpose – The purpose of this paper was to check effectiveness of amine functional chloroaniline acetaldehyde condensate (AFCAC) as a new curing agent for diglycidyl ether of bisphenol A (DGEBA) resin. For this purpose, first AFCAC was synthesised, characterised and then curing reaction was carried out. Design/methodology/approach – Equimolecular mixture of AFCAC and DGEBA was subjected to curing reaction, and the reaction was followed by differential scanning calorimetry (DSC) analysis. The kinetic studies of this curing reaction were also carried out from those DSC exotherms. The mechanical properties, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) of cured epoxy were also reported. Findings – DSC results reflected the effective first order curing reaction of AFCAC with epoxy resin. Mechanical properties reflected appreciable rigidity of AFCAC cured epoxy matrix and TGA showed that the cured epoxy networks were thermally stable up to around 297°C. Research limitations/implication...

Effectiveness of amine functional aniline furfuraldehyde condensate as toughening agent for epoxy resin

Purpose – The purpose of this paper is to find a new toughening agent for diglycidyl ether of bisphenol A (DGEBA) resin and to check effectiveness of this new toughening agent to obtain toughness and chemical resistance of cured epoxy.Design/methodology/approach – For this purpose, an investigation was carried out to synthesise, characterise and to study the toughening reaction of amine functional aniline furfuraldehyde condensate (AFAFFC) with DGEBA resin. AFAFFC was first synthesised from the reaction of aniline and furfuraldehyde in the acid medium (pH‐4) and characterised by FT‐IR spectroscopy, elemental analysis and concentration of primary and secondary amine analysis. Then various formulations were made by mixing DGEBA, AFAFFC and ambient temperature curing agent triethylene tetramine (TETA) in different compositions and the modified networks were evaluated to their mechanical and thermal properties. The dynamic mechanical analysis (DMA), scanning electron microscopy (SEM) studies and thermogravime...