If there is good interface, there will be secondary bonding among nanofillers and the polymer. It is expected that there will be upward shift of degradation temperature of the polymer. However, shift may be very low. Experimentation must be precise. May be you have to repeat the experiment by increasing/decreasing the scan rate.

Hi Samy El-Gamal ,

Just an add up to the previous answer (which I personally think is accurate): TGA can also be linked to Gas Chromatography and Mass Spectrometry. The technique is called TGA-GCMS. The main feature is the analysis of what is being released while your material is degrading in TGA. All the volatiles are separated with the GC, and then analyzed with the MS. If you have the chance to perform this type of experiment, and if you have a chemical bond between your filler and your polymer, you will certainly observe a difference in the released volatiles when comparing the composite and the pure polymer.

This technique also allows, after careful analysis of the results, to establish a degradation mechanism for the polymer. There are some papers related to this if you are interested.

Finally, the best way to observe bonding in a composite is normally FTIR. If there is a chemical bond between your polymer and your filler, some changes in the signals of the functional groups might be seen.

Hope this helps, and best of luck!

Based on your question, TGA does not directly provide bonding information. For this purpose, mass spectrometry can be used to study bonding interactions. However, there are weak van der Waals forces between the polymeric chains and the nanofillers, which slightly increase the thermal stability. This can be observed by comparing the original polymer with its composites.

TGA/DTG could be a valuable technique for assessing the thermal behavior of compounds, particularly in nanocomposites. To evaluate the effectiveness of filler-polymer interactions, it is essential to first analyze the thermal behavior of the filler and polymer individually. Changes in decomposition temperature either enhancement or reduction can indicate these interactions. To further investigate bonding interactions between the nanofiller and polymer matrix, techniques like FTIR should be used to identify characteristic bonds in each component separately. Shifts/Appearances of new bands in the composite related to filler and matrix can then provide insight into the formation of new interactions.

As other mentioned above, combination of different methodesis more usefull. Type of polmer matrix also indicate how to use and which method. Interesting point is complare polymers, fillers and then their blend. May be question to discuss can be rubber compounds filled by carbon black and/or silica + recycled materials. Identification of quality? Morphology ? Dispersion ? etc.

you will get a decomposition temperature higher than the base polymer, stability will be more.

If there is a bond between the substrate and the material, the decomposition temperature will be higher than that observed with weak van der Waals forces. This can be observed in the TGA results.

Once nanocomposites form with nanofillers and monomers such as benzoxazine. We can able to tell that bonding formation is not direct but by increasing decomposition temperature and char yield. If a nanofiller is well-bonded (chemically or strongly physically) to a polymer, it will:

• Restrict polymer chain mobility
• Slow down heat-induced degradation
• Leave a higher char yield due to better thermal resistance and inorganic content

If the interaction is weak (filler just physically mixed), the improvement will be minimal.

You run TGA curves for:

Signs of Strong Bonding in TGA

a. Shift in Onset Decomposition Temperature (T₅% or T₁₀%)

• Well-bonded filler: onset temperature shifts to higher values → stronger thermal stability.
• This happens because filler–polymer bonding hinders volatile degradation product escape and increases the energy required to break bonds.

b. Increase in Maximum Decomposition Temperature (Tmax)

• Peak temperature in the derivative TGA (DTG) curve is higher if the filler bonds strongly with the polymer.

c. Increased Residual Mass (Char Yield)

• Metal oxides are thermally stable → act as heat shields and promote char formation.
• Strong bonding helps form a protective barrier, reducing weight loss and increasing residue.

d. Multi-step Degradation Changes

• Sometimes, good filler bonding can merge degradation steps or change their intensity.
• Weakly bonded fillers may show a separate degradation step for unbound polymer.

Example

If you add TiO₂ nanoparticles to a polymer:

• Weak interaction: T₁₀% might rise only 5 °C; char yield increases mainly due to inorganic residue.
• Strong interaction (e.g., surface silanized TiO₂ forming covalent bonds): T₁₀% can increase 20–40 °C, Tmax shifts upward, and char yield increases significantly due to synergistic heat shielding and crosslinking effects.