Azomethine ether-based potential curing agent for epoxy resin (diglycidyl ether of bisphenol A): Synthesis and characterization (original) (raw)
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SYNTHESIS, CHARACTERIZATION AND SOME PROPERTIES OF EPOXY RESINS CONTAINING AZOMETHINE BONDING
New epoxy resins were prepared from hydroxyl substituted Schiff base monomers in two steps. The first step is based on the synthesis of hydroxyl substituted Schiff base monomers via condensation reaction. The second step includes the reaction between Schiff base monomers with epichlorohydrine (EPC) to obtain epoxy resins. The structures of resulting compounds were confirmed by FTIR and 1 H-NMR. TG-DTA and DSC measurements were made for thermal characterizations of the compounds. Chemical resistances of the cured epoxy-amine systems in acidic, alkaline and organic solvents were determined for coating applications. HCl (aqueous solution, 10%), NaOH (aqueous solution, 10%), DMSO, DMF, N-methylpyrrolidone, ethanol, THF and acetone were used for corrosion tests. Chemical resistance data show that the synthesized resins have good chemical resistance against various acid, alkaline and common organic solvents.
Journal of Applied Polymer Science, 2009
New photosensitive materials containing photochromic azobenzene moieties were synthesized. For this purpose, an epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) was reacted with an azobenzene chromophore (disperse orange 3, AZ) to satisfactorily synthesize an azo-modified prepolymer, which was then used to generate series of epoxy-based polymers containing azo groups. Three different amines were used as hardeners, with the aim of obtaining materials with different chemical structures. Understanding the epoxy resin polymerization kinetics is essential for intelligent processing of materials. Near-IR (NIR) spectral analysis was used to follow the polymerization kinetics. The quality of the NIR spectra enables concentrations of individual chemical species to be measured in real time. Conversion of epoxy and primary amine groups, as well as the concentration of different groups, as a function of reaction time was therefore calculated by this spectroscopic technique. Samples containing azo units were compared to the pure DGEBA/amine systems. Results showed that the azo-prepolymer incorporation has an accelerating effect on polymerization rate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Albaydha University Journal, 2023
A photoresponsive epoxy resin containing benzylidene units in the main chain has been prepared from bis (4-hydroxybenzylidene) cyclohexanone and epichlorohydrin using solution polycondensation method. The resulting compound possessed both the oxirane ring and benzylidene units. Thus, it has been highlighted in practical applications. The chemical structure of epoxy resin was characterized by Fourier transform infrared (FT-IR) and (1H, 13C) nuclear magnetic resonance (NMR) spectroscopies. The photolysis via [2π + 2π] cycloaddition reaction of the epoxy resin in the chloroform solution was studied by the UV-irradiation (350 nm). The thermal properties results show that the resulting epoxy resin is stable until 350 °C and its glass transition temperature is about 140 °C, which they were examined by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively, to demonstrate its potential in the industrial coatings.
European Polymer Journal, 2000
New epoxy polymers containing copper, cobalt and nickel ions have been prepared by curing diglycidyl ether of bisphenol A (DGEBA) with the Schi base complexes of these metal ions. The Schi base ligand was prepared from 2,4-dihydroxybenzaldehyde and 1,3-diaminopropane. Characterization of the metal complexes were carried out using infrared spectroscopy and elemental analysis. Tetrabutylammonium hydroxide was the most suitable catalyst for curing reaction. The introduction of metal ions, especially the copper ion, into the polymer matrices gave polymers with good thermal stability and mechanical properties, such as tensile strength. The copper-containing epoxy polymer obtained at a mole ratio of copper complex : DGEBA = 1 : 12 showed a 2.1% weight loss, after heating at 2508C for 48 h and had a tensile strength of 69 N/mm 2 , which is comparable to the epoxy-anhydride system. #
Journal of Applied Polymer Science, 2010
Vinyl-terminated benzoxazine (VB-a), which can be polymerized through ring-opening polymerization, was synthesized through the Mannich condensation of bisphenol A, formaldehyde, and allylamine. This VB-a monomer was then blended with epoxy resin and then concurrently thermally cured to form an epoxy/VB-a copolymer network. To understand the curing kinetics of this epoxy/VB-a copolymer, dynamic differential scanning calorimetry measurements were performed by the Kissinger and Flynn-Wall-Ozawa methods. Fourier transform infrared (FTIR) analyses revealed the presence of thermal curing reactions and hydrogen-bonding interactions of the epoxy/VB-a copolymers. Meanwhile, a significant enhancement of the ring-opening and allyl polymerizations of the epoxy was observed. For these interpenetrating polymer networks, dynamic mechanical analysis and thermogravimetric analysis results indicate that the thermal properties
Iran Polym J, 2008
A sulphone-nitrogen containing heterocyclic ring, tetraphenylthiophene diamine (TPTDA) was prepared and used as curing agent together with triphenylphosphine (PPh 3) to cure diglycidyl ether of a bisphenol A-based epoxy resin (DGEBA). Activation energies (E a) for curing DGEBA/TPTDA and DGEBA/ TPTDA/PPh 3 systems by using DSC data and Kissinger equation are 66.6 kJ/mol and 76.6 kJ/mol, respectively. The increase in E a can be due to polymerization of DGEBA by PPh 3 and formation of larger molecules with reduced mobility before curing with TPTDA to start. E a of thermal degradation of cured DGEBA/TPTDA and DGEBA/TPTDA/PPh 3 systems by using TGA data and Horowitz-Metzger equation are 56.0 kJ/mol and 128.0 kJ/mol, respectively. The onset decomposition temperature and the char yield have increased from 230ºC to 320ºC and from 21.4% to 32.5% for the above systems, respectively. The addition of PPh 3 to the curing mixture enhanced char formation and improved thermal stability of the resin.
Materials Research, 2005
This work involved the application of luminescence spectroscopy under steady-state conditions to study the curing process of the epoxy resin diglycidyl-ether of bisphenol-A (DGEBA) using the curing agents 4,4'diaminodiphenylmethane (DDM) and 4,4'-diaminodiphenylsulfone (DDS). Two fluorescence methods were employed: the intrinsic method related to the polymeric matrix and the extrinsic method, using the molecular probe 9-anthroic acid (9-AA). Stoichiometric mixtures, with and without 9-AA, were heated to 120 °C at a 5 °C/min heating rate. These samples were then cured at 120 °C for a further 2 hours and allowed to cool to room temperature for 20 minutes. The results obtained by the two methods indicate that the cross-linking reaction can be monitored by analyzing the spectral changes of the emission bands of DGEBA, curing agents and 9-AA.
Journal of Thermal Analysis and Calorimetry, 2010
A new homologous series of curing agents (LCECAn) containing 4,4 0-biphenyl and n-methylene units (n = 2, 4, 6) were successfully synthesized. The curing behaviors of a commercial diglycidyl ether of bisphenol-A epoxy (E-51) and 4,4 0-bis(2,3-epoxypropoxy)biphenyl (LCE) by using LCECAn as the curing agent have been investigated by differential scanning calorimetry (DSC), respectively. The Ozawa equation was applied to the curing kinetics based upon the dynamic DSC data, and the isothermal DSC data were fitted using an autocatalytic curing model. The glass transition temperatures (T g) of the cured epoxy systems were determined by DSC upon the second heating, and the thermal decomposition temperatures (T d) were obtained by thermogravimetric (TG) analyses. The results show that the number of methylene units in LCECAn has little influence on the curing temperatures of E-51/LCECAn and LCE/LCECAn systems. In addition, the activation energies obtained by the dynamic method proved to be larger than those by the isothermal method. Furthermore, both the T g and T d of the cured E-51/LCECAn systems and LCE/LCECAn systems decreased with the increase in the number of methylene units in LCECAn.