Storage stability and curing behavior of epoxy-dicyandiamide systems with carbonyldiimidazole-Cu (II) complexes as the accelerator

Liu, Xiangdong; Zhao, Chun; Sudo, Atsushi; Endō, Takeshi

doi:10.1002/pola.26744

Cited by 18 publications

(14 citation statements)

References 32 publications

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“…The curing process of epoxy oligomers under the influence of DCDA was studied quite well in the last half century [15][16][17][18][19][20][21][22], and the large number of possible mechanisms of the occurrence of reactions of interac tions with DCDA, its products of destruction, and epoxy oligomers and activating additives has been described recently; however, the detailed mechanism of interaction of DCDA has not been worked out yet. Basic schemes of the reaction of interaction of DCDA and products of its destruction with epoxy groups are shown below.…”

Section: Resultsmentioning

confidence: 99%

A study of the mechanism of curing of the dicyandiamide-epoxydiane oligomer system in the presence of asymmetrical urea

Chursova¹,

Ткачук²,

Panina³

et al. 2015

Polym. Sci. Ser. D

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Catalyzed epoxy systems have been studied consisting of an ED 20 epoxy diane oligomer ED 20, a curing catalyst (dicyandiamide (DCDA)), and an accelerator (an asymmetric urea based on toluene diiso cyanate). The chemical composition and structure of the catalyzed epoxy systems have been established by IR and NMR spectroscopy in the initial and cured states. The influence of the composition of the complex catalyst system of curing on the mechanisms of chemical transformation of epoxy system has been consid ered. It is shown that the products of interaction of epoxydiane oligomers with DCDA in the presence of the accelerator-asymmetric urea of Dyhard UR500 brand-is a complex system consisting of chains of poly esters produced by a chain growth mechanism and amine sites, as well as interaction products of epoxy groups with imines, isocyanates, and hydroxyl groups with nitriles.

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Section: Resultsmentioning

confidence: 99%

A study of the mechanism of curing of the dicyandiamide-epoxydiane oligomer system in the presence of asymmetrical urea

Chursova¹,

Ткачук²,

Panina³

et al. 2015

Polym. Sci. Ser. D

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“…DMP‐30 (A1), EMI (A2), and Imidazole (A3) are common accelerators used in DGEBA‐DICY systems. Previous studies showed that the acceleration effect of CDI (A4) is larger than twice the amount of imidazole . These four accelerators are strong bases, and generally used as anionic initiators for various ring‐opening polymerizations.…”

Section: Resultsmentioning

confidence: 99%

“…Dicyandiamide (DICY), one of the most popular curing agents for conventional epoxy resins, has been widely used in many industrial applications such as laminates, prepregs, coatings, and adhesives . The epoxy‐DICY curing system generally cures to a hard product rapidly in the presence of effective accelerators such as tertiary amines, carbonyldiimidazole (CDI), imidazoles, and several N ‐aryl‐ N ′, N ′‐dimethylureas . However, the chemistry of EVO‐DICY curing systems has not been explored.…”

Section: Introductionmentioning

confidence: 99%

Carbonyldiimidazole‐accelerated efficient cure of epoxidized soybean oil with dicyandiamide

Zhao

Wan

Wang

et al. 2013

J. Polym. Sci. Part A: Polym. Chem.

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This study investigates the curing of epoxidized soybean oil (ESO) using dicyandiamide (DICY) and combinations of DICY with several accelerators as curing agents. The differential scanning calorimetry (DSC) results indicated that carbonyldiimidazole (CDI) is a highly efficient accelerator for the ESO‐DICY curing system. CDI accelerated ESO‐DICY curing system can gel within a short period of 13 min at 190 °C. The activation energies of the ESO‐DICY curing systems with and without CDI are 95 and 121 kJ mol−1, respectively. Similar acceleration effect was observed in the ESO‐diglycidyl ether of biphenyl A (DGEBA) blending formulations. When the molar part of the glycidyl epoxy groups of DGEBA was equal to the internal epoxy groups of ESO in the mixture, gelation of the DICY curing system accelerated by CDI was achieved in 3 min at 160 °C. Furthermore, the DSC results with FTIR analysis suggest that the stoichiometric curing molar ratio was 3 ESO epoxy units per 1 DICY molecule. Two epoxy units reacted with DICY to give secondary alcohols, while the other one linked to the nitrile group. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 375–382

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“…The first way is the use the accelerants (acety lacetonates of various metals and substituted urea [15][16][17]), salts and complex compounds of tertiary amines [18], and imidazole derivatives [19][20][21]; the second way is chemical modification of DCDA.…”

Section: Introductionmentioning

confidence: 99%

The influence of composition of the dicyandiamide-asymmetric urea complex curing catalyst system on the thermal effect of the epoxy diane oligomer polymerization reaction

et al. 2015

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To decrease the curing temperature of epoxy compositions at the use of dicyandiamide (DCDA) as a latent hardener, a curing catalyst system including, in addition to DCDA, asymmetric urea has been stud ied. The dependencies of parameters of chemical transformations in catalyzed epoxy compositions, such as thermal effects and conversion, on the composition of the complex curing catalyst system have been estab lished by the DSC and isothermal calorimetry techniques. It has been shown that the chosen optimal com position of the catalyst system allows curing the epoxy compositions in a two stage regime at lower tempera tures than in the case of the use of DCDA.

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Storage stability and curing behavior of epoxy-dicyandiamide systems with carbonyldiimidazole-Cu (II) complexes as the accelerator

Cited by 18 publications

References 32 publications

A study of the mechanism of curing of the dicyandiamide-epoxydiane oligomer system in the presence of asymmetrical urea

A study of the mechanism of curing of the dicyandiamide-epoxydiane oligomer system in the presence of asymmetrical urea

Carbonyldiimidazole‐accelerated efficient cure of epoxidized soybean oil with dicyandiamide

The influence of composition of the dicyandiamide-asymmetric urea complex curing catalyst system on the thermal effect of the epoxy diane oligomer polymerization reaction

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