Polymers
TGDDM/DICY epoxy cure kinetics and properties
Open access · cc by · source: Europe PMC
FTIR and non-isothermal DSC show TGDDM/dicyandiamide cures in two autocatalytic stages, then a stiff, low-water-uptake network.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Bulk FTIR of a TGDDM/DICY epoxy maps a two-stage cure that DSC then clocks. Epoxy (906 cm⁻¹) is consumed as DICY amines become OH; nitriles 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; diffusion dominates at α > 0.85. Cured plaques give 12.6 MPa shear at 200 °C, εr = 3.26 at 1 MHz, and 0.41% water uptake. FTIR here is stepwise oven cures, not in situ DSC-IR.
Evidence for the claim as stated.
Site-specific 2D IR couplings and a bulk epoxy FTIR trace are not the same vibrational experiment. +8.3 versus +2.5 cm⁻¹ reports secondary structure at L12A13; 906 and 1687 cm⁻¹ report consumption of epoxy and appearance of amide in a thermoset. One is a labelled peptide kinetic; the other is a cure fingerprint. Calling both 'we ran IR' hides that.
Evidence for the claim as stated.
The TGDDM/DICY thermoset paper is indexed with TGA but the quoted thermal numbers are DSC and FTIR, not a mass-loss curve. Epoxy (906 cm⁻¹) is consumed; nitriles become amide (1687 cm⁻¹); two DSC peaks split at α = 0.45 with Kissinger Ea 69.7 then 88.7 kJ mol⁻¹; total enthalpy is 797–867 J g⁻¹ independent of heating rate; diffusion dominates at α > 0.85. Cured plaques: 12.6 MPa shear at 200 °C, εr = 3.26 at 1 MHz, 0.41% water uptake. DSC enthalpy is not a TGA residue.
Evidence for the claim as stated.
DSC of a curing epoxy and TGA of a filled catalyst are both 'thermal analysis' and are not interchangeable. Kissinger Ea 69.7/88.7 kJ mol⁻¹ and 797–867 J g⁻¹ are heat-flow results on TGDDM/DICY; the pumice paper's TGA is an unquoted mass-loss characterisation beside 0.5164 cm³ g⁻¹ BET and an 8 min nitro reduction. Quoting a cure enthalpy as if it were a TGA ash content is the mix-up.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Site-specific 2D IR couplings and a bulk epoxy FTIR trace are not the same vibrational experiment. +8.3 versus +2.5 cm⁻¹ reports secondary structure at L12A13; 906 and 1687 cm⁻¹ report consumption of epoxy and appearance of amide in a thermoset. One is a labelled peptide kinetic; the other is a cure fingerprint. Calling both 'we ran IR' hides that.
DSC of a curing epoxy and TGA of a filled catalyst are both 'thermal analysis' and are not interchangeable. Kissinger Ea 69.7/88.7 kJ mol⁻¹ and 797–867 J g⁻¹ are heat-flow results on TGDDM/DICY; the pumice paper's TGA is an unquoted mass-loss characterisation beside 0.5164 cm³ g⁻¹ BET and an 8 min nitro reduction. Quoting a cure enthalpy as if it were a TGA ash content is the mix-up.
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.
Inspect source passages
TGDDM/DICY epoxy cure kinetics and properties
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
Kissinger activation energies are 69.7 and 88.7 kJ mol–1
The typical Kissinger plots of the two cure processes were drawn in and the calculated activation energy values were 69.7 and 88.7 kJ mol −1 , respectively.
Total curing enthalpy is 797–867 J g–1 independent of heating rate
The total curing reaction enthalpy, which ranged from 797 to 867 J g −1 within the experimental errors limit (5% of the average value), was independent of the heating rate.
Key findings
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.
Methodology
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.
Limitations
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.
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