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Efficient accelerating effect of carbonyldiimidazole on epoxy-dicyandiamide curing system

Authors

  • Xiang Dong Liu,

    1. Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, College of Materials and Textile, Zhejiang Sci-Tech University, Xiasha Higher Education Zone, Hangzhou 310018, People's Republic of China
    2. Molecular Engineering Institute, Kinki University, Kayanomori, Iizuka 820-8555, Japan
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  • Atsushi Sudo,

    1. Molecular Engineering Institute, Kinki University, Kayanomori, Iizuka 820-8555, Japan
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  • Takeshi Endo

    Corresponding author
    1. Molecular Engineering Institute, Kinki University, Kayanomori, Iizuka 820-8555, Japan
    • Molecular Engineering Institute, Kinki University, Kayanomori, Iizuka 820-8555, Japan
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Abstract

Carbonyldiimidazole (CDI) was inventively used as an accelerator for the curing reaction of diglycidyl ether of bisphenol A (DGEBA) with dicyandiamide (DICY) and a high acceleration more effective than imidazole in double usage was observed. This result implies the accelerating role of CDI in the curing process is complex and involved not only the release of imidazole. To detail the accelerating mechanism of CDI, a series of curing reactions was studied by differential scanning calorimetry (DSC), NMR, IR, and viscosity monitoring. The results suggested that the accelerating mechanism of CDI involves (1) acylation of DICY with CDI to give the corresponding adduct with enhanced solubility, (2) the consequent release of imidazole that can react with epoxide, and (3) abstraction of proton of DICY by the alkoxide moiety to give the corresponding DICY anion endowed with enhanced nucleophilicity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

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