Ammine adduct and Schiff base formation in the copper(II) 1,1,1,5,5,5-Hexafluoropentane-2,4-dione-ammonia system

1,1,1,5,5,5-Hexafluoropentane-2,4-dione (Hhfa) reacts with ammoniacal solutions of copper(II) salts at room temperature to form the ammine adducts Cu(hfa)2,NH3 and Cu(hfa)2,2NH3, and at elevated temperatures or on standing to form the Schiff base complex Cu(hfacim)2 (Hhfacim = 1,1,1,5,5,5-hexafluoro-4-aminopentan-2-one) The magnetic susceptibility data for Cu(hfacim)2 suggest the presence of exchange interaction and is best explained by using a S = � Heisenberg chain model with J=-0.18 cm-1.

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Thermal Healing, Reshaping and Ecofriendly Recycling of Epoxy Resin Crosslinked with Schiff Base of Vanillin and Hexane-1,6-Diamine

Polymers ◽

10.3390/polym11020293 ◽

2019 ◽

Vol 11 (2) ◽

pp. 293 ◽

Cited By ~ 12

Author(s):

Van-Dung Mai ◽

Se-Ra Shin ◽

Dai-Soo Lee ◽

Ilho Kang

Keyword(s):

Schiff Base ◽

Epoxy Resin ◽

Elevated Temperatures ◽

Relaxation Times ◽

Diglycidyl Ether ◽

Original Material ◽

Crosslinked Polymer ◽

Schiff Base Formation ◽

Hydrolysis Of ◽

Base Formation

A bio-derived dihydroxylimine hardener, Van2HMDA, for the curing of epoxy resin was prepared from vanillin (Van) and hexamethylene-1,6-diamine (HMDA) by Schiff base formation. The epoxy resin of diglycidyl ether of bisphenol A was cured with Van2HMDA in the presence of the catalyst, 2-ethyl-4-methylimidazole (EMI). The crosslinked epoxy resin showed thermal-healing properties at elevated temperatures. Moreover, the crosslinked epoxy resin can be reshaped by heating via imine metathesis of the hardener units. The imine metathesis of Van2HMDA was confirmed experimentally. Stress-relaxation properties of the epoxy resin crosslinked with Van2HMDA were investigated, and the activation energy obtained from Arrhenius plots of the relaxation times was 44 kJ/mol. The imine bonds in the epoxy polymer matrix did not undergo hydrolysis after immersing in water at room temperature for one week. However, in the presence of acid, the crosslinked polymer was easily decomposed due to the hydrolysis of imine bonds. The hydrolysis of imine bonds was used for the ecofriendly recycling of crosslinked polymer. It is inferred that thermal-healing, reshaping, and reprocessing properties can be implemented in the various crosslinked epoxy resins with the bio-derived dihydroxylimine hardener, albeit the recycled epoxy resin is of inevitably lower quality than the original material.

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The characterization of copper 4,4',4'',4'''-Tetrasulfonated phthalocyanine ([29H, 31H-phthalocyanine-2,9,16,23-tetrasulfonato(2-)-N29, N30, N31,N32]copper) and the α-form of copper phthalocyanine ([29H,31H-phthalocyaninato(2-)-N29, N30, N31, N32]copper)

Australian Journal of Chemistry ◽

10.1071/ch9810489 ◽

1981 ◽

Vol 34 (3) ◽

pp. 489 ◽

Cited By ~ 7

Author(s):

NT Moxon ◽

PE Fielding ◽

AK Gregson

Keyword(s):

Magnetic Susceptibility ◽

Copper Phthalocyanine ◽

Chain Model ◽

Heisenberg Chain ◽

X Ray Diffraction ◽

Magnetic Susceptibility Data ◽

X Ray ◽

Susceptibility Data ◽

Triclinic Unit Cell

Powder X-ray diffraction, e.p.r, and magnetic susceptibility studies on copper 4,4',4'',4'''-tetrasulfonated phthalocyanine, Cu(tspc), and α-copper phthalocyanine, αCu(pc), are reported. Cu(tspc) was found, by analogy with the previously reported structures of the α, β and γ forms of Cu(pc), to have a triclinic unit cell of dimensions a 26.9, b 3.8, c 25.6 �, α 89.9, β 90.0 and γ 95.5�. The e.p.r. and magnetic susceptibility data for both Cu(tspc) and αCu(pc) suggest the presence of exchange interaction. The magnetic susceptibility data are best explained by using an S = � Heisenberg chain model with J -0.84 and -0.71 cm-1 respectively.

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