TGDDM/DICY epoxy cure kinetics and properties
FTIR and non-isothermal DSC show TGDDM/dicyandiamide cures in two autocatalytic stages, then a stiff, low-water-uptake network.
Source
Reaction mechanism, cure behavior and properties of a multifunctional epoxy resin, TGDDM, with latent curing agent dicyandiamide
Study at a glance
- Design
- Other — FTIR/DSC kinetic analysis of TGDDM/DICY epoxy cure and cured-material properties
- N
- Polymer cure kinetics and materials testing — no sample N
- Population
- TGDDM/DICY epoxy formulations
- Outcome
- Cure activation energies and high-temperature adhesive/dielectric properties
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
They mixed stoichiometric TGDDM with micronized DICY, followed staged oven cures while recording FTIR, then ran DSC at 5–20 °C min–1. Kissinger, FWO, and Starink analyses mapped Ea(α). Cured plaques were tested for tensile/shear strength, dielectric constant, and water uptake versus DGEBA/DICY.
What they found
Epoxy (906 cm–1) is consumed while DICY amines become OH; nitriles then convert to amide (1687 cm–1). Two DSC peaks split at α = 0.45; Kissinger Ea is 69.7 then 88.7 kJ mol–1. Total enthalpy is 797–867 J g–1, independent of heating rate. At α > 0.85 diffusion dominates. Cured TGDDM/DICY has 12.6 MPa shear at 200 °C, εr = 3.26 at 1 MHz, and 0.41% water uptake.
The limits
What it doesn't show
Isothermal DSC and full rheology during gelation are not reported. FTIR peak assignments use stepwise oven cures, not in situ DSC-IR. Dielectric and water data are single-condition comparisons, not a full hygrothermal aging study.
Key terms
- TGDDM
- N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane, a tetrafunctional epoxy.
- DICY
- Dicyandiamide, a latent solid amine/nitrile curing agent with long pot life.
- Autocatalytic cure
- Rate that speeds as OH products catalyze further epoxy–amine reaction.
- Isoconversional analysis
- Model-free Ea versus conversion (FWO, Starink) from several heating rates.
- Diffusion control
- Late-cure slowdown when the glassy network limits reactant mobility (α > 0.85).
Flashcards
Research intelligence for this paper
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Quiz yourself
The second chemical stage of TGDDM/DICY cure is mainly
Common questions
What are the two chemical stages?
First epoxy + DICY N–H ring opening; then nitrile + generated OH → amide.
Where does the DSC split?
Around α = 0.45, matching two exotherms (185–220 and 277–313 °C).
Kissinger activation energies?
69.7 kJ mol–1 (amine–epoxy) then 88.7 kJ mol–1 (nitrile/OH stage).
Why use DICY?
Latent solid hardener: mixable, then long storage versus fast liquid amines.
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