Issue 15, 2018, Issue in Progress

Reaction mechanism, cure behavior and properties of a multifunctional epoxy resin, TGDDM, with latent curing agent dicyandiamide

Abstract

A novel resin system was prepared using the glycidyl amide type multifunctional epoxy resin N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) and latent curing agent dicyandiamide (DICY). The curing reaction mechanism of the TGDDM/DICY system was studied by Fourier transform infrared (FTIR) spectrometry and the non-isothermal cure behaviors of the mixture were investigated with differential scanning calorimetry (DSC) measurements. The FTIR results demonstrated that there were two main reactions occurring in the curing process of the TGDDM/DICY system. The DSC thermogram of the blend exhibited two different cure regimes in the temperature range of 140–358 °C, and the system experienced two autocatalytic curing processes with α = 0.45 as the boundary; the corresponding average activation energies calculated by the Kissinger method were 69.7 and 88.7 kJ mol−1, respectively. In addition, the correlation between activation energy Ea and fractional conversion α was determined by applying model-free isoconversional analysis with Flynn–Wall–Ozawa (FWO) and Starink methods. Results showed that both methods revealed similar trends and possessed approximately the same values at each fractional conversion. Activation energy varied greatly with fractional conversion and the possible causes behind the variations were analyzed in detail. The cured TGDDM/DICY exhibited outstanding mechanical and adhesive properties with tensile and shear strengths of 27.1 MPa at 25 °C and12.6 MPa at 200 °C, good dielectric properties with a low dielectric constant of 3.26 at 1000 kHz and a low water absorption of 0.41%.

Graphical abstract: Reaction mechanism, cure behavior and properties of a multifunctional epoxy resin, TGDDM, with latent curing agent dicyandiamide

Supplementary files

Article information

Article type
Paper
Submitted
11 Dec 2017
Accepted
02 Feb 2018
First published
21 Feb 2018
This article is Open Access
Creative Commons BY license

RSC Adv., 2018,8, 8248-8258

Reaction mechanism, cure behavior and properties of a multifunctional epoxy resin, TGDDM, with latent curing agent dicyandiamide

F. Wu, X. Zhou and X. Yu, RSC Adv., 2018, 8, 8248 DOI: 10.1039/C7RA13233F

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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