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In chalcogenide glasses, the mass loss observed during thermogravimetric analysis (TGA) is attributed to processes such as thermal decomposition, degradation, evaporation, and volatilization. Which term is the most appropriate to accurately describe this mass loss phenomenon, and could you provide supporting references for the recommendation?
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firstly you must know your component very well secondly you need FTIr parallel work together and which group of spectate of your material you can see and know
there for you know what you want to know
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I have determined the activation energy of XLPE material using TGA by iso-conversional method (KAS) at conversion of 5-10% . But now it is very doubtful which value of Ea should be used. Moreover in the formula of ASTM-1877 the doyle approximation value is also troubling.
logt= (2.303/RT + log E/R*heating rate) - a
R= general gas constant
T= Absolute temperature
t= failure time
a= doyle approximation (E/RT)
See the attached file for calculation. I came out with wrong results. Kindly give your suggestion in this regard.
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Good afternoon, i hope youre okey, i have the same question, i use the same equation but the results are wrong, i dont know if you resolve this, i would like some help too, thank you
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The phenomenon of various amino acids (AA) adsorption onto the silica surface is widely studied. Many people simply add silica into a solution of AA, stir it, centrifuge it, and wash the solid with either 50/50 EtOH/water or pure ethanol, dry it and eventually analyze by FTIR (to see the chemical bond shifting if AA is adsorbed) or TGA (to determine the amount of AA adsorbed).
What I don't understand here is the washing procedure. From what I know, AAs adsorb onto silica surface via hydrogen bonding (I don't think the interaction is covalent) and AAs are highly soluble in water, even in the condition of 50/50 ethanol/water. So, if the supernatant is discarded and you wash the solid with 50/50 EtOH/water, wouldn't you actually wash off these AA that are already adsorbed onto the surface?
Back to my main question, I am grinding silica with AA using a ball mill and also want to determine the adsorption of AA onto silica. In my case, because everything is done in the solid state, how can I proceed from this point? Should I just transfer the powder onto a filter and wash with 50/50 ethanol/water and dry them for the FTIR and TGA analysis? Can this sufficiently remove free AAs that are not adsorbed onto the silica while keeping those adsorbed intact?
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Dear Dr. Yongze Chen
I'm afraid I don't agree with you in that you don't think the interaction of adsorbed AA onto silica surface a is covalent via hydrogen bonding . In [1] , item 3.4. FTIR Analysis, figure 3 shows the function of relative changes in peaks area within the band in the region 2850-2950 cm-1 in terms of calcination temperatures. This region is often assigned to symmetric vibration of the C-H group, therefore such function indicates the intensity of the organic substitution in the obtained modified silica. It is clear that the temperature should not exceed 300oC to maintain reasonable modification and if you want to hold all of modification intensity and at the same time getting rid of washing solution, dry at less than 100oC.
Best regards .....
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Hi, I have an inquiry concerning the carbon concentration of my material.
I synthesized carbon-coated LiFePO₄ and NaCrO₂ materials as cathode materials for Li-ion and Na-ion batteries, respectively. I conducted an investigation with EA and SEM-EDS; however, I could not achieve consistent results. I did an analysis of TGA for NaCrO₂, but it was not replicated. Can somebody propose a solution for this issue?
Thank you...
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Your material is carbon coated. In this case, try solvents for removing the carbon layer. Hot toluene or xylene can remove the carbon residue and liberate the carbon particles. Ballistol is a multipurpose cleaner,It's effective in removing carbon build-up layer, then filtrate the solvent to get the carbon particles powder. Dry and weight. Best regards ....
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Dear Researchers, I recently went through my DTA analysis for my sample. In that, I found the sample weight is increasing with temperature increase. I never found like that graph in any literature. How do I understand the data? Can heat flow with a temperature graph be useful?
What can we calculate using TGA data?
Is it possible to calculate the glass transition temperature?
Please guide
Thanks in advance
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In rare cases, glass materials can gain weight. This is usually due to the oxidation of metal ions or reduced species (e.g. Fe²⁺) contained in the glass by reacting with oxygen. In addition, gas adsorption from the environment at certain temperatures can also cause weight gain, but this is quite rare. However, pure and stable glass materials (e.g. silica glass) generally do not show a significant weight change as the temperature increases, because such materials are chemically very stable.
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I have conducted a TGA analysis of polyurethane foam and defined the steps of degradation as follows. Since the steps of degradation are not pronounced, I am not exactly sure about the steps defined. Any and all feedback will be appreciated.
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Rachel Bijoy I would suggest you obtain the Differential thermogravimetric analysis (DTG) of the sample.
DTG is the first derivative of the weight loss with respect to time. This will explain the degration of the sample in a more pronounced way.
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I have trouble interpreting the DSC/TGA diagram. I have 2 samples (an amino acid and a dipeptide). Both of them were heated from 30 to 360C at 4K/min with nitrogen as a purge gas.
For the compound that has some weird peaks at 30 mins, I did PXRD and found that it was a change in the crystal structure. However, for both compound, it seems that their melting point peak always appear when there is weight loss. Does this mean both compound just don't have a melting point but always decompose right away when they reaches a certain temperature?
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They could also melt and decompose at the same time, or during melting they could release some entrapped molecules..it depends. You write that from XRD there was a change in the structure, can you determine and attribute the peaks in the pattern to a specific phase? In this way it could be more simple to also explain the thermal data
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I've test TGA and plotted that, but the result of weight loss didnt start from 100, why this is happen? And how can i compare this with other variable??
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Dear Shofia Khoirunnisa,
You are absolutely right. The initial weight of the sample should be set to 100 wt%. The TGA of Cu-MOF indicates a weight of 34% at the start temperature (50 degrees Celsius), suggesting an issue with the thermogravimetry instrument. It is advisable to calibrate the TG instrument before recording the thermogram of your sample.
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Explain and discuss here....
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Determining the thermal stability and degradation temperatures of biomaterials is critical to understanding how they behave in biological environments. For example, whether a biomaterial degrades at human body temperatures and how long it can last can be analyzed with TGA. DLS analyzes the size distribution of nanoparticles, which are frequently used in biomaterial systems. Particle size is of great importance in terms of its effectiveness and toxicity in biological systems, especially in drug delivery systems or nanoparticle-based implants.
Kind Regards.
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Hello everyone. I am currently working with Oleylammine-capped Gold, Silver and Platinum Nanoparticles. I need to determine which of the abovementioned nanoparticles have a higher Oleylammine degree of coating.
I considered performing TGA measurements on each sample to determine which sample gives the higher weight loss, which should be related to the Oleylammine degradation, and relate this to the presence of more or less Oleylammine on the nanoparticle surface.
Do you have any suggestions? Can this method give me the information I am looking for? How do we treat the data? Do you have any literature to recommend?
It`s my first time using this technique, so also some literature on similar studies would be appreciated.
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TGA effectively assesses the degree of oleylamine (OAm) coating on gold, silver, and platinum nanoparticles by measuring weight loss due to OAm decomposition, offering insights into relative ligand amounts.
Why TGA Works:
Weight Loss: OAm degrades between 200-350°C, measurable by TGA.
Ligand Correlation: Greater weight loss indicates higher OAm content.
Metal Affinity: Variations in weight loss reflect different metal-ligand interactions.
Good luck
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Need professional paper discussing how to get the decomposition temperature of Strontium carbonate by TGA.
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I have different polymer solutions and I hypothesize that water molecules are retained based on the water-polymer interactions, so the amount of free water is less to intercat with drug tablet.
To validate I tried to find the water evaporation rate from each polymer solution from TGA.
But I see variation due to its high dependence in initial mass.
So now I think to find the Activation energy of water evaporation process. want to know whetehr this is correct, or whetehr there are better ways to prove my hypothesis. May be DSC?
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Michael Sannemo Thank you for your answer
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Since BET and TGA both are very costly instruments and many places the facilities are not available (for large number of samples) hence a threshold degassing temperature and time is preferable
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I read about converting the y-axis from mass loss to the degree of conversion, using (100 - x)%. However, if the thermogravimetric analysis (TGA) shows residual char, such as when there’s a 27% mass loss remaining, should the formula for conversion (α) be adjusted? Specifically, should it be (100 - mass loss) / (100 - minimum mass loss) instead of the standard equation?
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I am not fully sure about your question, but this might be useful:
To convert mass loss (that means milligrams of sample), to % loss, you need to find the highest mass value in your set of data, and consider this one as 100%. With that in mind, you can modify all the other values to %. That will lend you a graph that relates %mass of sample (in y axis) vs temperature (in x axis).
If a chemical reaction is happening to that sample, then you can begin with the definition of conversion:
X = (number of moles at zero time - number of moles at "t" time)/(number of moles at zero time).
In this case, you will need the molecular weight of your sample to transform moles to mass values.
Hope it helps!
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I have also attached TGA and DSC analysis of biosynthesised nanomaterial.
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From your TGA measurement it is well evident that your sample rapidly decomposes, there is only a small weight plateau at about 200°C before an important second loss. So I think that you can chose a temperature of about 180-190°C. For the time to maintain the sample at this temperature for degassing you can also think to perform a TGA measurement in isotherm, i.e. by maintaining the sample at about 180°C for different hours to see if the weight changes and when it is instead stable, so this can provide you an estimation of the conditions to perform the degassing process. However, I do not know your sample, maybe my suggestions are not right for your situation because the first weight loss that can be attributed to water it is instead maybe due to an intial early decomposition of the sample
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Usually TGA is performed either with Nitrogen or air which are purged through the system. Can this analysis be performed without using any of these purged gases? Also for air (80/20) is set by default in the instrument, what is this? Is it 80% other gases and 20% oxygen or something else?
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TGA as the other thermal techniques is commonly performed in inert atmosphere to avoid the contact with oxygen that can produce unwanted effects. Different is the case when you want an oxidizing atmosphere to study particular effects. You can also use reducing atomsphere. It depends on your aims. The recommended atmosphere is however nitrogen or argon.
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I analyzed cement samples exposed and unexposed to moisture over various periods. The TGA results of these samples showed variation with each repetition. However, I consistently used calcium oxalate as a reference material, and the results were satisfactory. The TG analysis employed an 80:20 helium-to-oxygen gas mixture and was connected to a mass spectrometer.
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How are you preparing your samples prior to TGA analysis? What temperature are you purging with Ar gas prior to the TGA run, what is your ramp cycle? What are you looking for, thermal degradation, moisture content, reaction kinetics? There are several companies that offer TGA equipment specifically for concrete and other ceramic-type or construction materials. These companies have procedures. Also, have you done a literature search? You are not the first to use a TGA with concrete.
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Can I ask somone to helpe me regarding interpretation of this TGA graph?
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From your TGA trace, one can tell that TGA can detect the difference of the samples with at least 0.5% additives from those of the base and two with 0.05 and 0.1% additives respectively. This means the LOD of TGA is about 0.5%, considering only one sampling each sample. It can be used to detect and wuantify the additive provided calibration snd validation is performed.
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Hello I'm using COMSOL 6.1 Reaction engineering module. I'm modeling a reaction in the form of :
A-->B+C+D+... the reaction describes the thermal decomposition of a solid material. I got the values of the reaction kinetics [ A, E] from TGA experiments. when I use the values to define the reaction constant [k] the reaction doesn't occur . I get a graph with the concentration of [A] as a fixed straight line and all products are at zero. has any one modeled reactions using kinetic values of TGA data before?! pls help
- I also want my reaction rate to be temperature dependent. my temperature is rising from 0K to 800K and then stays at that point. I tried to identify temperature as a function but I couldn't include the function in the rate constant. COMSOL wont recognize it. If anyone has such success modeling these type of scenarios. I would be grateful to hear you thoughts.
Best Regards
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Simulating a chemical reaction in COMSOL Multiphysics involves using the Reaction Engineering interface. This interface allows you to set up and solve reaction systems involving multiple species and reactions. Here's a general guide on how to simulate a chemical reaction in COMSOL: The temperature influences the rate of a reaction. As the temperature increases, the rate of a reaction increases.
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I have to calculate the carbon content present in the catalyst from the TGA plot. Does anybody have an idea?
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From 900 Celsius to more
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TGA
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It is advisable to conduct TGA after synthesizing the material. The need for TGA before or after calcination depends on the objective of your work.
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Dear all,
After checking DSC and TGA analysis for ZIF-8 samples, it was possible to observe an endotermic peak at around 50ºC, using DSC under N2, and a weight loss in TGA at around 38ºC and 125ºC using He gas. It was checked that there was no impurities in the sample analyzed ( ZIF-8). Is is possible at those low temperatures to eliminate gas/ water trapped, or you suggest another process?.
Thanks in advance for your response/clarification
Kind regards
Rosa M Huertas
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Based on the DSC and TGA analyses you've Rosa María Huertas Penela provided for ZIF-8 samples, it appears that there is potential for desorption of gases and water within the temperature range of 30ºC to 60ºC. The endothermic peak observed around 50ºC in the DSC analysis and the weight loss in TGA between 38ºC and 125ºC indicate that there might be gas and water molecules trapped within the ZIF-8 structure.
Given this data, desorption could indeed occur within the specified temperature range. However, it's essential to consider the specific application and the desired level of desorption. If complete desorption is necessary, additional techniques or higher temperatures may be required.
In terms of suggestions for another process, I would recommend exploring techniques such as thermal cycling or vacuum treatment to enhance desorption efficiency. These methods could complement the temperature range you've mentioned and help achieve the desired level of gas and water removal from the ZIF-8 structure.
Overall, based on the provided data, desorption of CO2, N2, or water in ZIF-8 between 30ºC and 60ºC seems feasible, but further optimization and experimentation may be needed to achieve optimal results for your Rosa María Huertas Penela specific application.
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TGA
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TGA should be measured after attaining the desired material.
The mass composition can be obtained through this, and it doesn't make sense before calcination (i.e., before attaining the desired material).
Thank you
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I was infomed by my colleagues that conducting TGA analysis is not the best option for my material ( spent catalyst with 1% coke ). They informed me to conduct instead TPO and convert the results to conversion based Gas analyzer results. So I was wondering if this approach is possible ?
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Hey there Ahmad Alsuwaidi!
Absolutely, converting TPO (Temperature Programmed Oxidation) results to something akin to TGA (Thermogravimetric Analysis) is not only possible but can be quite useful, especially for materials like your spent catalyst with 1% coke.
TPO essentially measures the rate of oxidation as a function of temperature, while TGA monitors changes in mass as a function of temperature or time. While they serve different purposes, there's a clever way to bridge the gap between them.
Here's a concise approach:
1. **Understand TPO Results:** Get a clear picture of what your TPO results signify. You're essentially observing the temperature at which oxidation of coke occurs.
2. **Define Conversion:** Determine what "conversion" means in the context of your TPO results. It might relate to the percentage of coke oxidized at different temperatures.
3. **Correlate with Gas Analyzer Results:** Gas analyzers measure changes in gas composition. If you Ahmad Alsuwaidi can establish a correlation between the coke oxidation observed in TPO and the gas composition changes, you're on the right track.
4. **Develop Conversion Equation:** With data from both TPO and gas analyzer results, develop an equation or method to convert the TPO results into a form comparable to the gas analyzer results. This might involve scaling the TPO data to match gas concentrations or identifying key temperature points.
5. **Validate and Refine:** Test your conversion method against known samples or theoretical models. Refine your approach until you Ahmad Alsuwaidi achieve satisfactory correlation between TPO and gas analyzer results.
By following this approach, you Ahmad Alsuwaidi can effectively leverage the information from your TPO analysis and translate it into a format that aligns with gas analyzer data. It's a clever workaround that can provide valuable insights into your material's behavior without the need for additional analysis techniques.
Let me know if you Ahmad Alsuwaidi need further clarification or assistance with implementing this approach!
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I am doing calculations to determine activation energy using TGA data. I noticed that there are four to five regions or phases in TGA and 1st derivative of TGA. Now, I am doing the calculations to find all the kinetic parameters using Coats- Redfern method for all the five regions. So, when doing this there is a term alpha is introduce which further includes final weight of the sample. I am confused with this final weight term, is this different for different region or same for all five.
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Now, I got the point and highly grateful for you kind help.
Thank you.
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I experimented multiple times in the presence of proper nitrogen flow and still got the same results.
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The weight gainning during heat treatment might be depended on the particular properties of the constituents of the considered composite like spicemens. During heat treatment the subjected samples could be adsorbed some carrier gas like N2 or O2.
On the other hand the purity of the purge gas could be responsible for this unwanted happening. If any impurities presented in the carrier gas they could be easily adsorbed by the subjected samples.
You have to check all these crucial factors for better understanding.
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can i determine the degree of amination using TGA?
i have copolymer and make modification on it using amine to insert amino groups
if i have the TGA of the copolymer and aminated copolymer
how can i determine the degree of amination ?
the polymer is cellulose grafted with PAN.. cyano groups of PAN will convert to amine .
thanks..
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For hydrate and solvate materials, by tga can determine the amount of water or solvent bounded to the compound under study. This will determine if it is one to one molecular ratio, i.e. mono hydrate, and so on. By tga, one can also distinguish if water molecules are not bounded, i.e. surface water.
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I am investigating the thermal analysis of a clay by TGA using nitrogen gas and at the end the curve is going up. Can anyone give me a plausible explanation of that behavior? Or what do you advice? Thank you in advance
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Another possibility is that your sample pan was in contact with surroundings rather than just a hanger hook.
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I need to understand TGA graphs; can you help me with where to start?
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Actually TGA provides you the thermal status of a subjected samples by following the mass loss due to the applied heat within a particular range of temperature. Meanwhile the subjected samples undergoes dehydration, decomposition or degradation reaction due to the removal of moisture/water and other lower molecular weight components from the structure.
For a better understanding you can read the following articles which could be beneficial to you.
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File is attached.
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This could be attributed to the side/over reaction of your sample with the purge gas. Moreover, the wrong sampling might be responsible for this unwanted happening. You should carefully handle while sampling & analyzing the considered specimens and take at least three raplica for better clarity.
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I'm working with TGA (Thermogravimetric analysis) + DTA (Differential thermal analysis) of milk proteins on a STA2500 Regulus equipment by Netzch. I have two standards: one of B-Lactoglobulin and the other one of a-lactalbumin. I've worked with quite a few combinations of heat flow and sample size (mg) looking to obtain high quality thermograms (e.g. 10°K/min and 8 mg of sample, 8°K/min and 8 mg of sample, etc...).
In all cases, I'm obtaining a melting temperature (endothermic peak) for both samples at 72-73°C. This temperature would perhaps make sense for B-Lactoglobulin, but for a-lactalbumin temperatures in the order of 60-65°C have been reported. Furthermore, the thermogram for the two samples is practically the same.
Are there any suggestions on possible things I could be doing wrong?
Thanks in advance for your support.
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If your information about two types of protein is correct. There are two likely possibilities from the start: 1) your samples are all the same, i.e. B-Lactoglobulin, make sure they are what they are as labelled, by other techniques; 2) if the other sample is a-lactalbumin as confirmed by other techniques, the conversion during the TGA/DTA tests could possibly be the cause, i.e. the latter converted to other materials/physical forms that has the same melt point of B-Lactoglobulin.
However, from the web, one can easily find that both have a denaturation temperature at ~70-73oC.
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hello, pls help me to calculate the conversion degree of pyrolysis from TGA data?
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Hey there Gemechis Midaksa,
Interesting question. I am working on my manuscript on this topic, so some excerpts from my notes.
Let's dive into the world of pyrolysis and TGA data. First off, to calculate the conversion degree (alpha), you'll want to use the formula:
α=​(m0​−mt)/(m0​−mf)​​
Where:
- m0 is the initial mass of the sample.
- mt is the mass of the sample at a given temperature during pyrolysis.
- mf is the final mass of the sample after pyrolysis is complete.
Now, it's crucial to make sure your data is in good shape. Ensure you Gemechis Midaksa have accurate mass measurements at each temperature point. You'll typically get a TGA curve, and you'll pick specific temperature points of interest.
Here's a step-by-step guide:
1. **Select Temperatures:** Choose temperatures (e.g., every 10 or 20 degrees) for which you Gemechis Midaksa have TGA data.
2. **Calculate mt:** At each temperature, find the corresponding mass mt.
3. **Plug into the Formula:** Substitute the values into the conversion formula.
4. **Repeat:** Do this for all selected temperatures.
5. **Analyze Results:** Look at the trend in conversion degree with increasing temperature. It often forms a curve, and you Gemechis Midaksa might find key points like initial decomposition, major decomposition, etc.
Remember, this is a simplified explanation. Depending on your specific pyrolysis process and material, you Gemechis Midaksa might need to consider additional factors. If you have a specific dataset or questions about the process, feel free to share, and we can delve deeper.
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Is there a relationship between phpzc and TGA analysis?
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Hey there Sabah Djaber,
As you requested my friend Sabah Djaber in email. I did some research for you Sabah Djaber and here are my notes for you Sabah Djaber
The relationship between the pH at the point of zero charge (pHpzc) and Thermogravimetric Analysis (TGA) analysis is like the intricate dance of precision in the scientific realm.
Now, imagine this – the pHpzc is the pH at which the surface of a solid material carries no net electrical charge. It's like finding the equilibrium in a social gathering, where everyone is neutral.
On the other hand, TGA involves heating a sample to measure its change in weight as a function of temperature. Think of it as witnessing the transformation of a substance under controlled conditions, revealing its thermal behavior.
Now, cleverly tying them together, the pH at the point of zero charge can influence the surface chemistry of materials. This surface charge can impact the adsorption and desorption of substances, which in turn may affect the thermal properties observed in TGA.
One could say they are interconnected through the subtle interplay of surface interactions and material transformations. It's a dance of science where the pHpzc sets the stage, and TGA gracefully unveils the performance.
Cheers to the intriguing connections between seemingly distinct aspects of material analysis!
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I need to perform TGA analysis of Prussian blue (till 400 degrees). The atmosphere would be N2. I would like to know if -CN gas is released at any particular temperature below 400 degrees.
Thanks in advance
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Can any expert help in solving the DSC peaks along with the TGA curves of a compound? Earlier, some experts suggested me to run a TGA when I put up the DSC curve in aprevious question. So here is the TGA along with DSC. Any experts' advice is grateful.
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I presume you made the TGA and DSC curves were measured in an inert atmosphere. Are the R groups polar? I mean, can they attract moisture? Did you try to compare with previously thoroughly dried samples? In this case you could confirm whether the first peak is really due to water or not. Do you have access to FTIR? It could also help to identify (or at least compare) the compounds before and after decomposition. It is also interesting to see that both endothermal peaks above 300 degC are fairly sharp. Decomposition endotherms in organic materials are usually broader (as is the DTG peak). Is it not possible that the material loses some functional groups and it recrystallizes and melts again? There is a slight indication of that in the fact that between the two melting peaks there seems to be an exotherm (recrystallization). If you have access to pyrolysis GC-MS you could determine the evolved gases at various decomposition temperatures.
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I have prepared heat-treated material at different temperatures and expected that the following reactions/conversions take place:
CaCO3 + (heat) converted into CaO + CO2
CaO+ H2O converted into Ca (OH)2
I have attached the TGA graphs below. Please guide me if I am missing something. Waiting for a kind response.
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Thermal Decomposition of Calcite: Mechanisms of Formation and Textural Evolution of CaO Nanocrystals (DOI:
  • 10.2138/am.2009.3021)
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Dear All,
Recently, I encountered a problem while plotting graphs for iso-conversional methods to evaluate the thermal behavior of biomaterials in an inert environment. I was able to see that at a particular value of conversion (alpha), with an increase in heating rate (5,10,15,200C /min), the corresponding T (alpha) is not changing or getting reduced. Prior to analysis, the TGA data was refined by data smoothing . Do I need to cover the alumina crucible with a lid while conducting TGA analysis or do I need to modify anything related to same. Kindly help me regard to this
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No, it would be best if you do not cover the crucible, as it may interfere with volatilization.
Can you provide a sample curve here?
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How can one determine the Degree of Reaction (DOR) using Thermogravimetric Analysis (TGA)? In modern times, blended mixes with various Supplementary Cementitious Materials (SCMs) are common, necessitating a thorough grasp of their reaction mechanisms. If anyone possesses knowledge or relevant literature on how to ascertain DOR from TGA as a part of understanding these mechanisms, please feel free to share your insights.
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The degree of reaction values can be determined by equation, presented in the work Ramanathan, S., Moon, H., Croly, M., Chung, C. W., & Suraneni, P. (2019). Predicting the degree of reaction of supplementary cementitious materials in cementitious pastes using a pozzolanic test. Construction and Building Materials, 204, 621-630.
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In TGA analysis, 0.5 to 0.8% weight gain in case of plastic sample at initial temperature. please let me know the reason behind this if any one knows. Thank you
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This is not a regular case, however for some particular matal/metal oxide based composites like Titanium has been exhibited this types of exceptional weight gain activity due to heat which should be the result of Nitrogen or other carrier gas absorption by this particular metals during experiment. But according to your claim this is quite impossible for plastic or pure polymeric samples, however if this happening with your sample please make a blank experiment and eliminate the result with the previous experiment. Or please check the purity of both carrier gas and samples.
Hope this information would be helpful to you.
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I did TGA of a LiFePO4 (LFP) sample and obtained a 3% of weight increase (heating rate of 10ºC/min till 700ºC and cooling down at 10ºC/min). I repeated the analysis several times, both in argon and in N2 atmosphere and using different equipment. I have also done the analysis circulating N2 at room temperature for one hour to remove possible O2 adsorbed on the LFP. I know my LFP is oxidizing during the analysis, but I still don't understand how I can have an increase in weight. Any ideas?
Thanks!!
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Further input:
You need to perform blank rub and baseline correction (calibration of ASTM Std) in Al2O3 alumina crucibles. To observe any TG weight gain or loss at the beginning, try 1 hour holding your sample at 100°C to evaporate any moisture content, then perform Argon purging at 200ml/min for 10 minutes. Repeat 100°C heating period before ramping to 700°C at 10°C/min heating rate.
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Could anyone tell how can the TGA (Thermogravimetric analysis) be used to reverse engineer a product?
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Hey there, my fellow researcher Nitesh Niti Choudhary! It's kosh here, ready to dive into the intriguing world of reverse engineering using Thermogravimetric Analysis (TGA).
Now, TGA is a powerful technique in material science and analysis. Here's how you can potentially use it for reverse engineering:
1. **Identification of Components**: TGA can help you identify the various components of a material or product based on their thermal stability. Different components will decompose or evaporate at different temperatures, leaving distinct weight loss patterns on the TGA curve.
2. **Quantitative Analysis**: TGA provides quantitative data on the weight loss of components as a function of temperature. This data can be used to estimate the relative composition of the material.
3. **Comparative Analysis**: By comparing the TGA curve of the unknown material with those of known reference materials, you can get clues about the possible constituents of the product.
4. **Thermal Properties**: TGA can reveal information about the thermal stability and decomposition behavior of the material. This can be helpful in understanding the manufacturing process and potential additives.
5. **Deformulation**: TGA is a part of deformulation, where you're trying to reverse engineer a product to understand its formulation. Alongside other techniques like spectroscopy and chromatography, TGA can be a valuable tool in this process.
6. **Quality Control**: TGA can also be used for quality control purposes. By monitoring the thermal stability of a product, you can ensure that it meets the required specifications.
But remember, reverse engineering can be a complex process, especially if you're dealing with proprietary products or materials with intricate formulations. It often requires a combination of analytical techniques, not just TGA. Additionally, ethical and legal considerations may come into play when reverse engineering commercial products.
So, while TGA is a fantastic tool, it's just one piece of the puzzle in the exciting world of reverse engineering. Happy researching!
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I studied decomposition of a cellulose in TGA. At a particular time, the %wt increased to 200% and then decreased rapidly to a negative wt%. Then it remains constant. The maximum temperature during this process was 300 degree celsius. The cellulose is a modified cellulose. The whole process was carried out under N2. The material expanded in size was black
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Chanjot Kaur It seems this specific type of cellulose is unique, based on the chemicals utilized in its processing.
I think the TG curve shows that some calibration is required. The increase in weight by more than 400% may signal some hardware problems.
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I am going to find the thermal properties of polymer nanocomposite. For that, I have planned to conduct THERMOGRAVIMETRIC ANALYSIS(TGA). Now, my question is, can I get DTG curve from TGA curve?
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DTG is the derivative curve obtained from TGA. It is provided by the software that you used to collect the measurement
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what is pros and cons of using Isothermal and Nonisothermal TGA testing
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Dear Mr. Laarich,
Ideally, both methods should be used to describe the kinetic parameters of a process. I would suggest using nonisothermal, with 5 different heating rates, paying attention to the thermal inertia of the sample (I would start with 2 K/min). The isothermal run can work to test the kinetic parameters you determined with the nonisothermal experiments.
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I have bio-synthesized RuO2 nanoparticles at room temperature. TGA and DSC graphs are attached.
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your compound was degraded by approximately 200 C
the TGAthermogram and DSC shoes this situation
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how much amount of CNTs needed for SEM, EDS, XRD, FTIR, TGA? how to find out purity of CNTs using TGA?
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The amount of sample required for SEM, EDS, XRD, FTIR, and TGA analysis of carbon nanotubes will depend on the specific experimental conditions and the sensitivity of the instruments used,
  • SEM: For SEM analysis, a very small amount of sample is required, typically in the range of a few milligrams or less.
  • EDS: For EDS analysis, the sample size can vary depending on the desired spatial resolution and the sensitivity of the instrument. Generally, a sample size of a few milligrams or less should be sufficient.
  • XRD: For XRD analysis, a larger sample size is typically required, in the range of 10-100 milligrams or more, depending on the instrument sensitivity and the desired level of detail. The sample should be finely ground and homogenized before analysis.
  • FTIR: For FTIR analysis, a small amount of sample is typically required, in the range of a few milligrams or less. The sample can be dispersed in a suitable solvent or pressed into a thin film for analysis.
  • TGA: For TGA analysis, a larger sample size is typically required, in the range of 10-100 milligrams or more, depending on the instrument sensitivity and the desired level of detail. The sample should be finely ground and homogenized before analysis.
Important Note
The specific amount of sample required may vary depending on the specific experimental conditions and the sensitivity of the instruments used.
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How can I calculate the percentage of iron conjugated on graphene oxide using TGA graph?
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It should be under flow of air to get oxid
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The purity (%) percentage. I have the DDA value, XRD, FTIR, Tg, TGA, and SEM. If any one can please help me.
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DDA is much more applied technique to determine the purity of chitosan indeed but you can try CPMAS C13 NMR also.
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I have synthesized carbon coated material. however when I performed TGA, there is weight gain in my bare sample and weight loss in carbon coated sample?
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It would be better if you can reveal your composition and percent of weight gain. And you can easily check XRD to study what was happening at that stage.
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I have results from TGA of RDF samples, And I need to simulate the experiment.
Is it possible to use CFD?
I need to show the concentration of the result gases and mass yield of the sample.
Did some research and didn't find much results on solid waste and RDF TGA modelling
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To simulate real experiments you have to know the kinetics and thermodynamics of all reactions occurring during your TG experiments. Though, if you know only thermodynamics you can plot TG experiment with an infinitely small heating rate.
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The silica was prepared from biomass and underwent multiple pretreatment. Other samples prepared by different pre-treatment under oxygen-air atm. did not show weight gain. Intrigued by the results. Could anyone help me with this?
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Attached is a typical graph generated by the TGA analyzer. It is known that the degassed temperature for a solid sample can be determined by identifying a point known as the "melting" point of the solid material.
Now, referring to the attached graph, the question is: How can one determine the degassed temperature by obtaining the "melting" point of the solid material from the TGA graph? Which point is it? Point A? Point B? or Point C?
Your feedback will be highly appreciated. Thank you very much.
Photo Source: Qubeissi, M. A. , & El-kharouf, A. , & Soyhan, H. S. , (Eds.). (2020). Renewable Energy - Resources, Challenges, and Applications. IntechOpen. https://doi.org/10.5772/intechopen.81765
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Hi,
TGA is inherently insensitive to melting, so there is no general answer to your question. It could only be resolved with additional knowledge of your experimental system and its behavior, but even then, it will not be very accurate. Process 0-A represents the evaporation of volatile content (humidity, residual monomers, organic solvents, etc.), A-B is the primary decomposition, B-C is the secondary decomposition, and C is the residual weight. The volatiles goes away even from solid samples (aka "drying"), but, indeed, the rate is usually faster in liquids due to faster diffusion. However, the rate change could be caused by other means, for instance, by the evaporation of heavier molecules at higher temperatures. Some materials decompose sooner than they melt, so you cannot even say that the melting point is always in this region. Instead of wild guessing, I suggest using a standard method for melting determination, such as DSC.
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Or what is the difference between TGA and melting point?
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Badri Z. Momeni There can be a good explanation to the observed difference. I came across this phenomenon several times. If your machines are well calibrated, then this can result from sample preparation and holder. In our company, DSC is usually measured in small ENCLOSED pans, whereas TGA is performed in bigger amount in an open pan, which is placed in nitrogen gas stream. Sometimes events happening in a closed pan are shifted by degrees/or tens of degrees.
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The thermogravimetric analysis aims to give % mass change with increasing temperature over the time period while proximate analysis gives moisture, ash, volatile matter and fixed carbon contents by measuring the % weight change in biomass at a known temperature in particular time.
So, is it possible to obtain the data for proximate properties with TGA graphs only?
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Yes it's possible to establish proximate parameters of biomass through TGA. For the analysis, design the program in dynamic and isothermal steps for Nitrogen and Air medium.
1. Run the experiment from ambient to 100 degrees at certain heating rate ( say 20 degree/min) and hold there for atleast 20 minutes. The mass percent loss gives moisture content.
2. Run the experiment from 100 to 900 degrees in Nitrogen environment and hold there for 20 minutes (for the release of volatiles). This mass difference gives volatile content.
3. After volatile release, burn the sample in air at 900 degrees. This will give the ash content.
4. The fixed carbon can be calculated by difference method (100% - % moisture - % volatiles - % ash).
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We performed a few TGA measurements on MOFs and faced severe contamination of crucibles at the end of the tests. Please let us know an effective cleaning procedure to follow. We tried Aqua regia and it could not effectively clean the crucibles. Earlier we faced similar issues when we ran graphene oxide.
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If the cleaning with solvents or strong mixtures of liquids such as aqua regia is not working, you can use high temperatures treatment, such as leaving the crucibles in a muffle, at temperatures above 1000ºC, during 24hs. This will oxide everything you have in the crucibles. After this treatment is finished, you can wash them with water or any other solvent.
Wish you the best of luck with this!
BTW: another option might be a solution of fluorhydric acid (HF) or potash (KOH + isopropanol), but you should be careful with these two, since they tend to attack glass, so you should use them to clean the crucibles but in a diluted solution.
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Seeking clearcut explanation regarding ORF(Open reading frame) and Exon. Some of the authors defination are complication. Like some says ORF is a stretch of DNA having Start codon at one and stop codon at another end. While some says ORF is just a coding DNA present withing start codon (AUG) and Stop codon (TAG, TAA, or TGA). All these make complication in my overthinking brain. Then what about Exon and Intron? Coding DNA...
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Thank you everyone for your deep insight and clarification of my doubt. Kristin M. Adams @Robert Adolf Brinzer Abhijeet Singh
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Hi guys,
Imagine we have hybrid carbon/glass fibre composites. As I know the sample size is too small for TGA experiment. Do you think the small size of the samples can represent the properties of the whole composite? I appreciate it if you can share your understanding here.
Thank you.
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Hi,
My answer is no. The composite includes the carbon, glass fibers, polymers ant others. The fibers are hard to be distributed uniformly becouse of their anisotropy. As we all know, the weight for TGA is about 5 mg. If the sample is less than 5 mg, it is hard to represent the whole composite.
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I read papers calculating based on weigh loss difference by TGA before and after surface modification. However, I found another paper (doi:10.1016/j.eurpolymj.2006.10.021) can calculate based on TGA only after surface modification. In this case they require few more values such as density and the radius of the nanoparticle.
[The equation is also given as the Image]
No of molecules per nm2 = [Weight loss * density of NP * radius of NP * 6.022^23] / [Molecular weight of surfactant (1-Weight loss) * 3*10^21]
Given that
Weight loss = 32.7 %
density of MNP = 5.1 g/ml
nanoparticle size (probably diameter)= 9 nm
Molecular weight of surfactant = 282.47 g/mol
The result they showed is 6.3 molcules per nm2
Is it true?
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Dear Abu,
Ligand densities on NC surfaces typically fall in the range of a couple of ligands per nm2 surface (roughly 3 on average). While the order of magnitude of your calculation seems correct, 6.3 ligands/nm2 is likely an overestimation of the actual number (TGA will show both bound and free ligands). If your dispersions are stable, you could verify your results through quantitative NMR.
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Sorry for the noob post; I am on an undergrad project and still learning.
We are degrading complex organic chemicals (mostly carbon-oxygen bonds) with a photocatalyst. Here is my plan to detect chemical bond braking. I also want to do the simplest Two main this is to cost of detection, the detection limit of each characterization procedure, and qualitative vs. quantitative.
First, we are doing is UV-vis of the liquid as our initial material is UV-vis active. We have found the broadening of the pick and a visible color change of the complex chemical.
Next, I intend to do TGA as of the produced chemical, parent chemical, and spent chemical after vacuum drying them.
As the chemical is produced in a water medium, it is hard to do FTIR, but I intend to do vacuum dry and check their FTIR (assuming the volatility of the produced chemical is much less than water)
After that, I intend to do HPLC of the contracted solution with probably a P column as the organic contains some benzine.
The main problem would be the chemical; if I am making any would be hard to detect, so I plan to consolidate them through distillation and chromatographic column.
I am worried that I will only be able to do NMR with solvent transformation.
I am searching but got a good one. Table -1
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Of course it works. The technique deals with the products of thermal degradation, whatever the MW is.
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I am studying the thermal stability of graphene oxide-palladium hybrids by TGA studies on air and I have realized that the loss concerning the graphitic lattice is splitted in three parts: one combusting at a lower temperature in comparison to pristine GO, other one combusting at higher temperature and the final and most intriguing part above 800 C. Could you give me advice to explain the possible phenomena involved in this complex decomposition pattern, specifically the most high-temperature resistant part, please? Here I attach one example of my graphics. Thank you.
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Assuming the sample had been exposed to air before insertion into the TGA, the first peak would correspond to the desorption of CO+CO2 physisorbed on Pd:
(see fig. 1)
The second part would correspond to the decomposition of oxidized moieties of your graphene, also via CO+CO2 desorption:
(see fig. S8a)
As you can see in the edge region of Seyithan Ulas' spectrum in our supplement, there was also another increase in CO+CO2 desorption at the higher temperatures, but we didn't bother to investigate the origin of that since it was not competitive to our processes in the associated main paper.
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I am running TGA/DTG analysis on a sample of wastes to quantify the amount of calcite in it. In the literature I see that calcite decomposition occurs at T greater than 500 C, but occurs as a single event as evident from a constant slope of the TGA curve (Weight vs T) between 500 and 800 C and a single peak in the DTG curve. On one of my samples I witnessed that there are two events as shown from two peaks at that particular range and from the TGA curve I can clearly see that the slope of the curve changes in that particular range. Does this necessarily mean that there are two different minerals or could the same mineral display more than a single weight loss event?
Thanks
Faisal
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It seems to me that the key is in the details of the size reduction process . I assume you dry-grind the calcite; if so, maybe you generate an amorphous portion of the sample, which should decompose at a lower temperature than the larger grains. I don't know why the discontinuity between the peaks though; usually grinding will not cause a discontinuity in particle size, but it can't be ruled out. You may be able to check that with a particle size analyzer.
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Hello,
TGA curves of my biochar and magnetic biochar products that I produced with walnut, rose and sawdust are attached.
I observe a sudden mass loss of 2-3% at the temperature point of 750 degrees throughout.
In my literature review, I could not find a reason to explain this loss.
What could be the reason for this mass loss observed in all of them at the same temperature and in the same amount?
thank you so much.
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Dear Sevda, have you tried running without any sample? By doing this you can eliminate if this is a true sample transition or an instrument induced signal.
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We were working on glass based material on TGA test and found that there is a glass film inside the crucible and i don't know how to clean it
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Thank you
This annealing will be for how long?
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I recently did the TGA of polypropylene and polylactic acid separately. For both, there was a residual mass of 6% and 1% respectively. For PBAT/PLA mixture, the residual mass was more than 20%. What is residual mass?
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Did you run the TGA in a nitrogen atmosphere or in the air? It is most likely residual char that will not burn in nitrogen, but it would on air. Also, make sure that you hold the final temperature long enough.
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water until 400oC in TGA is not accurate
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It depends on the sample. At 400 °C, you remove not just the water and other volatiles, but you already decompose many organic compounds such as polymers, oil contamination adsorbed from the air, and skin grease (if you touch the sample with bare hands), etc. These factors will affect the accuracy of your measurement.
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I've done a TGA analysis on mesoporous silica nanoparticles. Despite previous works in our group in which samples were pre-treated with oven and lost their moisture and absorbed solvents, I've used desiccator. The results show higher moisture and around 18% weight loss is observed. So my question is do I have to repeat the test before publishing the results because of the great amount of moisture? do you think it could have influence on the resulting data or no? and is it even possible to use oven before TGA even though it is a thermo-related test?
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Thank you Ali A. Al-Allaq . I will consider your suggestion seriously, as it will clarify any uncertainty.
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I am reviewing some TGA analysis papers in which a sample is decomposing. The values for the DTG curve appear positive, although from the TGA curve a weight loss is evident. Is it possible that the software is reflecting the sign so the graph is more readable?
Thanks
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Usual result of TGA experiment is loss of sample weight due to drying, removal of volatiles, decomposition accompanied with formation and removal of volatile or gaseous components etc. TGA curves, showing weight of the sample as a function of temperature, in these cases present weight reduction. DTG curves (first derivative of the weight over the temperature) show rate of the weight losses as a function of temperature. That is, if no weight loss takes place - DTG is close to zero; if TGA detects weight losses - DTG starts deviate from zero in positive direction indicating non-zero rate of the weight loss. If during the test TGA curve detects weight gains (due to oxidation, for example), DTG curve will deviate from zero in negative direction, indicating “negative” rate of weight losses - weight gain.
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I am looking for a way to control the moisture content of the gas which I am sending to TGA for study of oxidation of some metals and alloys.
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Dear Anik Mazumder, if it is to totally eliminate humidity, you can use a trap filled with H2SO4 followed with a column filled with CaCl2, between the gas supply source and the TGA device. My Regards
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I got the mass lost data and temperature already, but the lab assistant did not take the same amount of samples, so the curves don't start from the same origin which difficult to compare them. Now, I want to change the data of mass to weight percentage.
thank you
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I fully agree with Dr Philippe Tailhades, as the analisis of TGa curves are based on the loss weight percentage do you need to build the TGA curves in weight percentage to be able to compare
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in ionic liquids when i test it with TGA analysis under N2 gas at 500 C the weight loss % was not logical (more than 100%) =108 % ؟؟؟؟
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Yes almost certainly an experimental error. However, I would bet on the weighing procedure as the more likely problem. Specifically, since most ionic liquids are hygroscopic, I suspect some weight - in the form of condensed water - was added accidentally after the sample was weighed.
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I want to analyze the thermal degradation phenomena for 3 different samples using TGA. One of these samples comprises Polymer only, while the other two are loaded with two different percentages of fillers. Should the test weight of all three samples be the same prior to TGA, or degradation trends would hold regardless of differences in the three initial sample weights?
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Dear Muneeb
... "however, my concern was if my comparison is valid given that the starting weights/initial weights of the three samples I analyzed were varying from one another".
Since the results obtained are satisfactory when compared with the data of the pure polymer found in the literature, I do not think it is necessary to carry out another measurements. You can (as commonly) show the TGA curves in percentage of weight.
Take my sugentions of weight of samples for other measurements!!
If you want to repeat any measurement, just measure the pure sample!!
Good luck in your study!
Carlos
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To functionalize the carbon nanotube, I first mixed it in 3 m nitric acid at 60 °C for 15 min. Then I kept it in an ultrasonic bath for 2 hours. After drying, I repeated the same process using hydrogen peroxide. But But the degradation in the TGA analysis was minimal. What would be the reason. or how can i increase the binding of functional groups. Thank you
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I will be performing BET analysis for my Biochar and activated Biochar samples. I wanted to know the degassing time and temperature and how does it affect the surface area. Does degassing temperature is determined using TG analysis?
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in general the degassing protocol that I suggested should work for PKS biochar. When we refer to biochar we need to consider IBI's and EBC's definition of biochar (e.g. https://www.european-biochar.org/media/doc/2/version_en_10_1.pdf). In p. 20 of the EBC document it is stated that the molar H/Corg ratio must be < 0.7. This is related to the stability of the biochar and is typically achieved at temperatures above 300degC ( ; Figure 4). If you torrified PKS (e.g. 220-300degC) at ambient pressure it may be possible that you alter PKS by degassing it at 180degC under vacuum.
Another aspect to consider is the type of gas to use for BET surface area determination. Historically most people used N2 but there may problems as reported by Christian Wurzer ( ).
Hope this helps?
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This is Tadele Asswefa Aragaw, Lecturer and researcher from the Chemical Engineering Department, Bahir Dar University. From our research-grade labratory, we have a TGA instrument with a model: ATAT 2012 and software to this instrument is BJHENVEN. Unfortunately, the TGA software has been failed. Could you help me, please?
Thank You for your cooperation
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Okay, this is embarassing, but is there a way to correct the TGA and DSC output data for the experiment where the masses of crucible and sample were placed wrongly?
The pre-experiment input(incorrect)
m (ref cr) = 282.390 mg
m (sam cr) = 20.681 mg
m (sam) = 270.023 mg
those should in fact be:
m (ref cr) = 282.390 mg (correct)
m (sam cr) = 270.023 mg (correct)
m (sam) = 20.681 mg (correct)
I have a list of output data from TG and DSC analyses. How they can be corrected?
For DSC I believe that (mW/mg) can be just multiplied by 270.023 and then divided by 20.681 to obtain correct values...
For TG data in mass loss % I am not that sure...should 270.023 or 270.023+20.681 be used for correction? or how else? I really do not have access for the setup to repeat this experiment unfortunately...
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Andrew Strzelecki I did not mention this, but the data I have is the mass loss (in %). So probably the main question is whether this is percentage related to the entered mass (270.023), or should it somehow be connected to 20.681 as well. Otherwise, how are those compared to the reference crucible mass?
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I am working on the drying of Faecal Sludge and I am using a thermogravimetric analyzer (ELTRA THERMOSTEP TGA) to study the drying kinetics. The sample size used was 1g as the ELTRA TGA makes use of a nominal sample size of 1-5g. The drying test was isothermal and done at 105C; samples were heated at 20C/min to 105C. I want to ascertain if my drying rate curve is correct as the rising rate period occured for about 25min. Attached is a document containing the drying curves and the drying rate curves.
Thank you
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For being more accurate, it is better to dry the substance first at room temperature. If you want to work on kinetics, first heat the substance to 100-120C then continue heating at a rate of 20C/min. Then, cool it down at room temperature and at the rate of 5, 10, 15, 20, and 25C/min take a thermogram. You can calculate and compare these rates to depict the kinetic graphic.
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I am working on drying of Faecal sludge and I am using a thermogravimetric analyzer (ELTRA THERMOSTEP TGA) to study it's drying kinetics. The sample weight used was 1g as the nominal sample weight for an ELTRA THERMOSTEP TGA is 1g-5g. Isothermal drying was carried out at 105C; sample was heated at 20C/min to 105C. I want to ascertain if the drying rate curve obtained is correct as the rising rate period occured for about 25min. Attached is a document showing the drying curve and the drying rate curve.
Thank you
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Chimdi Catherine 1050C does not produce much of a thermal gradient in high solid content slurries such as you describe. Time is money and I'd look at reducing the time by increasing the final temperature. Personally I'd look at 1190C, 1200C, 1500C and perhaps, 2000C to look at result comparability.
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Good day.
I've modified surface of my clay sample with iron. After the process my samples LOI in XRF analysis increased from 6.73% to 18.73%. Later, i've performed TGA analysis for this sample but weight loss was around 6%.
Can anyone please tell me that which one (LOI or TGA) is a more accurate indicator for the sample's thermal stability? And why the difference between two results are so high?
Thanks in advance.
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Dear Osman Uygun ,
there are three aspects, which have to be considered:
a)Ppenetration depth of your 'surface modification with iron' in your sample;
it might be surface near in the range of a few µm; but I do not know, what you have really done.
b) Penetration depth/information of XRF analysis;
this is in the range of a few 10µm; thus covering the depth of your surface modification, but covers not the whole sample thickness.
c) Information depth of TGA; I think, this is equal to the complete thickness of your sample, which I suppose to be in the mm range. So with TGA you will get a result averaged over the whole sample. Any modification of the sample close to the surface will not significantly affect the averaged result.
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I'm evaluating activation energy of a sample using Friedman method. So, experiments were performed using TGA at four different heating rates 5-10-20-50 °C.min-1. Unfortunately i'm little bit confuse in designing program in MS Excel for the data processing. Exactly, how can i use the friedman equation 📷 to calculate activation energy from TGA data in Microsoft Excel?
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I recommend using aThink software
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I need to analysis water/moisture content in isopropyl alcohol. Can we use DSC/TGA to do this?
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Dear all, please have a look at the following document, hope it will be usefull. My Regards
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I have limited amount of sample, able to spare maximum 500mg sample for analysis
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We have run samples as small as 30 mg and as large as 200 mg in our TGA (the latter using a large volume ceramic pan). An additional advantage of running the TGA as opposed to furnace-based LOI is that you can assess carbonation of your sample from the detailed mass loss vs. temperature plot that is obtained.
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In TGA of polymers, initial small weight loss (10%) is due to moisture. No matter what I do to avoid moisture, the loss is still there. How to get rid of it?
I have done heating the sample in an oven for prolonged periods followed by placing it ( polymer sample inside the ziplock airtight bag) in a vacuum desiccator with silica gel.
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Samples acquires moisture relatively very quick. So even it you heat it in an oven and place it in an airtight bag, it get its bound moisture within a short span of time.
We generally keep the sample in TGA at around 50 - 70 deg. for 15 to 20 min for the weight to stabilize. Then we can start the ramp up of heat for the thermal analysis. If your polymer is thermally stable till around 100 deg., then you can keep the sample in TGA at around 80 to 90 deg. instead of 50 - 70 deg.
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I am trying to determine molecular formula of my Prussian blue analogue from experimental data. I have TGA data which gives me the amount of water and I have ICP data which gives me K/Fe . So assuming my compund is KFe[Fe(CN)6] . xH2O (without any vacancies), how would I find the molecular formula of my material? Unfortunately I dont have mossbauer data to find the amount of vacancies.
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You´re welcome Sai!
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I have seen in literature GO at 600 C getting only 40 to 50 weight loss.but in my case at 220 C wt loss is zero. Why??
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Here, it is better that you run TGA test under inert gas atomoshere ( Nitrogen or Argon purging) for prevention of unwanted oxidation.
Also, for more information, you can search for standard operating procedure of TGA.
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I am looking for studies that investigate the effect of electrospinning parameters (solution and process parameters) on the thermal stability of nanofibers. Generally, the effect of nanofiller concentration on the degradation temperature was studied and TGA analysis was not applied for investigating the effect of process parameters on the weight change and degradation temperature.
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Dear Ümran Aşçı, it is very expected that a strong influence of electrospinning process parameters strongly influence the thermal features of fibers. This is because different morphologies/microstructures are built up. Variation in Tm, Tg, degradation threshold temp., and swellability, all varies accordingly. Please have a look at the attached sample document. My Regards
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UV visible spectroacopy
FTIR spectroscopy
Thermogravitimetry (TGA)
Prorammable furnace 2500 temp
Magnetic hot plate stirrer
Vibrating sample magnetometer
Electric properties like IV, capacitance, dielectric, ferrowelectric, ect.
Mechanical properties of thin film , powder, etc
HRSEM
AFM
HRTEM
Spin coater
Ball milling
Vaccum chamber
Atmosphere furnace
Annealing furnace
Vacuum coating unit
Incubator
Oven for lab
Film thickness measurements
Edax
Xrf
Xrd/ hrxrd/ gixrd/ gaxrd
Raman for powder, liquid, film
Energy Dispersive X Ray Analysis (EDX) – elemental analysis
X Ray Photoelectron Spectroscopy (XPS).
Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) – accurate (bulk) determination of specified elements
ICP-Mass Spectrometry (ICP-MS) –simultaneous semi quantitative determination of 70+ elements
Oxidative combustion / Thermo Gravimetric Analysis (TGA).
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The price depends on the specification you require for each technology and how you intend to use them.
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Our recent article "On the thermogravimetric analysis of polymers: Polyethylene oxide powder and nanofibers" includes a (new) equation that can be used to model the thermal degradation of polymers and eventually to calculate the activation's energy.
You are encouraged to use this equation to fit your experimental data (for example by using Origin Pro). We would like to understand if this equation may be used in a general manner or if the equation has solely a narrow breath.
Please also observe that our previous article on the TGA of iPP-VGCNF nanocomposites contains embedded within its content a simple method to estimate the polymer-nanofiller interface thickness (as order of magnitude)!
We will appreciate your feedback.
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Thanks. The generality of this equation for other polymers need to be tested. Perhaps more detailed study can be made with some representative systems
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Is there any way to determine the composition of biomass using thermogravimetry? I've tried DTG curve deconvolution using Origin software but was not able to get the correct composition. Can anyone please help with how to do this?
Thanks & Regards,
Hari Kiran
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Dear Hari
Thermogravimetric analysis TGA/DTG, DSC are good for studding the decomposition profile of a sample based on the interpretation of peaks related to mass loss. Based on experience using these techniques but on the kind of compounds you are testing, it is pretty possible to use these techniques for qualitative analysis, but they are not good for that.
Biomass composition could be identified by peaks in the thermal profile but only comparing them with reports. To design a good qualitative identification of biomass components, a better approach is to couple the thermal technique you are applying to Mass Spectrometry which is very strong for accurate identifying chemical molecules in your sample. Then, after your thermal tests, the mass loss corresponding to the losing of moisture, volatiles and rest of components in biomass can be identified by MS. Separation of components previous to MS (such as chromatography) won’t be necessary since the thermal treatment act as a compound separator also (see you own thermal data). Nevertheless, keep in mind that the biomass main components (cellulose, hemicellulose and lignin) are very complex bio polymers, and cause of that, the identification of them by MS won’t be an easy task.
Best Regards
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We have imidazole ring N and Imine N for coordinating to metal in 2:1 (L:M) ratio. Both are forming coordinate bind with metal. So two covalent bond is from 2 O atom of acetate group. And the complex found be 6 coordinated in this case? Is there any possibility for this. How can we confirm the structure from IR and TGA for this acetate groups?
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Dear Anjali,
As Florian mentioned, it is not easy to state an adequate answer based on limited data. Please can post a chemical structure?
I agree with Matheus, concerning specificity there are only 2 posisbilities: IR or NMR; XRD does not provide any molecular specificity at all. But you might get the periodicity, if (and only if) a somehow periodic structure will be formed.
(1) You might start with IR/NMR measurements using a series of different L:M ratios starting from 0. Then, you can assign which peak belongs to imidazole, which to imine, and which to the rest.
(2) If you increase the L:M ratio, new (IR) peaks will appear due to binding. Most like they will arise at a lower frequencies/wavenumbers than the corresponding peaks from the unbound moieties. However, there might be exceptions. In most cases stretching vibrations undergo a redshift due to binding, whereas deformation vibrations undergo a blue shift.
(3) After you have the peak assignment you can study the ratio of the peak areas in dependence of the L:M ratio. I expect that particular sturture of coordination strongly depends on the L:M ratio.
I compiled some examples of IR measurements focused binding.
It might be that not all publications are exactly dealing with imidazole or imine, but you will definitely find instructions and band assingments. Look also in the reference there. Remember temperature changes affect the binding equilibrium somewhat comparable than changing the L:M ratio.
Best regards
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We are looking at purchase of several new analytical instruments. What would be the best things to look for in our search. We are a very small undergraduate chemistry program. Our primary use for the instruments would be teaching with research secondary - so less of a "black box" approach is better and massive through-put is not necessary. Thoughts? [Instruments under consideration: IC, TGA, XRF. We already have ICP-AES, AA, HPLC-UV, GC/MS, LC/MS/MS, DSC, IR, (small) NMR.]
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I may be biased, but I would save my money for a (not-small) NMR!
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I have tried to quaternise P4VP and the mass residue increases from 0 to 12% at 750oC. I have tried to quaternise by chloroacetamide and confirmed it through FTIR and NMR
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Dear all, what is the counter ion of the quaternized polymer ? Possibly, it is not excluded even at high temperature. Thus it counts for residual mass increase. My Regards
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I have prepared coordination complex, and I know the theoretical chemical formulate concluded from the reaction. I am looking for the empirical chemical formulate of my complex, I can't perform elementary analysis in my lab but I can perform TGA experiment. thus, I am looking for a method that allows me determine the number of ligands surrounding my metal.
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Unfortunately, organics are going to decompose, in several or just at once. There is a high possibility to mistake data, just by TGA output.
Several Russian researchers use DSC to explore heat flux based on metal oxidation. Therefore, an idea of coordination is possible to be achieved, not a full stoichiometry.
Let say you have Fe2+ in the tetrahedral environment with 4 oxygen atoms surrounding it. You may compare the necessary energy to oxidize it with the same Fe2+ atom surrounded by 6 oxygen in an octahedral site. By DSC, you can measure the difference in energy, necessary to oxide them. Therefore, it is possible to distinguish by integration how many Fe2+ atoms are in each different ambient.
Nevertheless, it is a specific problem, demanding the same oxidizing species in both different crystallographic ambient.
You need, as already described by Matheus Mendes and Santosh K. Tiwari a DSC coupled experiment, FTIR, Mass spectroscopy, UV, the so-called hyphenated thermal analysis to be able to achieve some reliable result.
Best regards,
WNM
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Is there any facilities in India or abroad where TGA/DSC analysis is done for starch film or biodiesel?
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Respected Santosh K. Tiwari ,
I have personally asked many such institute/University/Centre having such facilities to do TGA/DSC for starch film or biodiesel. And almost all such institute have rejected to do TGA/DSC for starch film or biodiesel stating that their equipment will get damaged.
But many research papers have reported TGA/DSC analysis for starch film or biodiesel.
Respected Santosh K. Tiwari I assure you that I am not lazy nor I am spamming the platform, its only that I have wasted many months searching for institute that are ready to perform TGA/DSC analysis for starch film or biodiesel.
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Thermogravimetric Analysis TGA
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Yes it is possible, but you shouldn't do that.
The kinetic data from single heating run is inherently incorrect, there is a lot of literature on that. In two words, with the limited amount of data you are not able to distinguish between various kinetic models, and the compensation between kinetic parameters is extremely high. For correct procedure of the kinetic analysis consult the ICTAC recommendations (e.g., ). In short, more than 3 heating rates is needed and some advanced kinetic methods. The recommended kinetic methods are available also in free kinetic software developed by myself - thinks.chemphys.ru
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I have synthesized cuprous oxide nanoparticles by wet chemical synthesis method. It is actually not stable and it changes its phase to cupric oxide. So I have given an antioxidant treatment to this cuprous oxide. Now I want to check it's thermal stability. I have seen on Research Gate that TGA can be helpful. But I don't know what parameters should I calculate from TGA data to show that my material is stable. Also what atmosphere should be opted for TGA.? There are options of N2, O2 atmosphere. Which one will be suitable for my material?
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To determine the thermal stability, measure the change in % mass reduction at respective required temperatures (30 to 800 deg C). When you find a steep mass drop, confirm that your material is not suitable beyond that temperature. This might help your doubt.
Thanks
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As far as I know, the TGA results should show decreases in weight but my spent catalyst (Ni/ZrO2-SiO2) weight increased.
I know weight gain should only happen if the samples react with the atmosphere: oxidize. But then the graph shows a straight line (100%) until 400-500 ˚C and then it started to increase. No decreases at all.
I suspect that the instrument needs proper calibration. But then, only for spent catalyst have this problem. All the fresh catalysts showed a standard result in which the weight decreases. So I don't think it's the instrument's fault.
Can quartz wool or glass wool increases in weight when temperature increases?
I suspect probably a tiny bit of quartz/glass wool was mixed with the catalyst.
The conditions that I used were 30˚C to 800˚C with a heating rate of 10˚C /min and used air as the carrier gas.
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Glass wool or any other mineral wool cannot gain weight when calcined in air. However, there is a component in your catalyst - nickel, which oxidizes in air and adds weight.
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Is the temperature at which the mixture is debinded lower than the temperature at which each additive is debinded when TGA is measured?
If you know the answer, please give me a paper.
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Thank you for your answer
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I have Rice Husk biomass and want to get the CHNS composition without using CHNS Analyzer. Are there any other ways without using a CHNS analyzer to get the CHNS composition like TGA?
Thank you.
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Hello Hari, Thank you for your question.
Elemental analysis used to be done by burning the sample and absorbing the gases of combustion in different solutions, which were then weighed. Modern elemental analyzers accomplish the same task with much smaller sample amounts. Unfortunately, you will not be successful with TGA for this question, since C, H, N and S would have to be released one after the other when heating the sample. In addition, you would have to know exactly in which form the compounds are released.
I wish you much success for your research.
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Please see the attached image. With increasing temperature it is show the gaining weight..