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Research method

Thermogravimetric Analysis (TGA)

Thermogravimetric analysis records mass versus temperature (or time) as a solid is heated, usually under N₂ or air. Mass-loss steps report solvent/hydrate, ligand burnout, polymer decomposition, or how much inorganic residue remains. In this library TGA is often one tick in a materials characterisation suite — beside FTIR, SEM, XRD and XPS — while the numbers the papers actually quote are DSC cure enthalpy, a hydrate formula, catalyst loading via crystal size, BET porosity, or drug entrapment. Those are neighbouring thermal or composition experiments, not substitutes for a published TGA step table.

Polymer and materials chemists reach for TGA when they need to know what burns off and what is left. It answers 'how much mass leaves in this temperature window?' Its main limitation here is that several indexed papers never quote a TGA percentage in the teaching summaries: a characterisation list that includes TGA does not by itself give a decomposition temperature, and DSC of an epoxy cure is heat flow, not mass loss.

Studies

5

Findings

4

5 supporting · 0 challenging · 0 qualifying citations

Open tensions

2

Currently

What we know

  1. A magnetic Cu-on-pumice catalyst lists TGA among FT-IR, SEM, EDX, XRD, VSM, BET and XPS. The numbers that are actually reported are a working recipe and texture: 0.05 g catalyst at 70 °C reduces nitrobenzenes in 8 min; BET pore volume is 0.5164 cm³ g⁻¹; XPS shows Cu⁰ after reduction; the solid is magnetically recovered with gradual activity loss. TGA is supporting composition/stability characterisation, not the catalytic clock.
  2. 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.
  3. A Zn phenanthroline–maleate crystal is a hydrate whose formula matched elemental analysis; DSC and FT-IR/Raman sit beside SC-XRD. Geometry is distorted square pyramidal in P-1; Hirshfeld surfaces are 30.6% H···O/O···H and 9.0% C···C; periodic-DFT gap 3.45 eV; MIC 1000 μg/mL versus S. mutans. A hydrate is exactly the kind of solid TGA often quantifies — the teaching summary still does not quote a TGA water-loss percent.
  4. Loading that TGA might have reported as residual mass is instead given as a size/photochemistry knob. Immobilised Mn carbonyls in UiO-67-type bpy MOFs change crystal size from 260 nm to 1 mm, which changes loading and photoefficiency of visible-light CO release; cells on a polymer film of the MOF see intracellular CO after irradiation. NIR deep-tissue delivery is not shown. A chitosan–xanthan hydrogel similarly quotes 90.64% acyclovir DEE and 87.57% release at pH 7.4 (FCX8 76.83% DEE) rather than a TGA drug-loading step.

Largest unresolved question

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.

Common misconceptions

  • If the experimental section lists TGA, the paper’s main result is a decomposition temperature.

    The pumice catalyst’s headline is 8 min nitro reduction at 70 °C with magnetic recovery; TGA is one of eight characterisation methods. The epoxy paper’s thermal headline is DSC Ea(α) and 0.41% water uptake, not a TGA trace quoted in the summary.

  • Elemental analysis matching a hydrate formula is a TGA measurement.

    The Zn paper matches the hydrate by elemental analysis and uses DSC among other methods. TGA could in principle quantify lattice water as a mass-loss step; that percent is not in the teaching summary.

  • A TGA (or any thermal) characterisation of a drug gel or CO-MOF proves the dose that reaches a patient or a tumour.

    FCX6’s 90.64% DEE is a laboratory loading; human PK was not measured. The photoCORM MOF delivers CO into cultured cells under visible light; in vivo inflammation models are proposed, not completed.

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