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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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Extracted chitosan is generally characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) technique, and scanning electron microscopy (SEM).
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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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Alundum crucibles have an limit of usability. After several experiments (with appropriate cleaning), it is better to throw them out (including to improve the quality of subsequent experiments). This is a consumable item. And the glass is removed mechanically. Sometimes annealing works (800-1000) with backfilling with calcium or magnesium oxide (but not with alkali metal oxides). Backfill simply "absorbs" the glass, staying fragile.
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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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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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If you had indicated how the sample was obtained, it would have been easier to answer. It would also be nice to make sure (prove) that silicon is present there)). Of course, it would be nice to analyze the initial and final samples (after TG). Most likely it is water (remember silica gel, it adsorbs a lot of water), or the decomposition of residual organic matter.
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I am doing O2/CO2 research on Combustion and for that I recently need to run some tests on TGA machine model STA 449-F3. My query concerns the selection of Purge gas 1 on the software. This TGA allows me to select different gases only on Purge 1 while Purge 2 is fixed for a very few options. In my case, I have to use a mix of Oxygen and CO2. I have used 2 controller and a flow meters to mix the the gases in the required composition and then attaching to the input of Purge 1.
Now, my question is, does the selection of a Purge gas 1 on the software, has any effect on my results, where if the input mix remains the same?
like if I choose Oxygen as P1 on the software and input mix in actuality is 30% O2/CO2?
Secondly if I choose a previously defined selection option, in the software, of 30% O2/CO2 having density of 1.82 (as shown by the software) and still the input is the same as before, 30% O2/CO2, will the software change the results depending upon which P1 I have selected?
Are the results in this particular TGA, as per received cases?
Does any of the above assumptions and changes have effect on FTIR results?
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You wrote
1. "N2 gives a barrier or protection against oxidation more efficiently". More efficiently than what? What is an inert gases?
2. The thermal conductivity coefficients of helium is almost an order of magnitude larger than argon (or nitrogen), but I have never heard of helium being used as a purge gas. Still, the price matters, for helium it is much higher. By the way, inert or inactive gases are also distinguished by the content of oxygen ...
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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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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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Dear Dr.Mangrola,
We have a company in which we manufacture low-cost and yet very precise magnetic devices including vibrating sample magnetometer (VSM) with high quality and different options; Giant Magnetoresistance (GMR), Magnetizer, Thermomagnetic Treatment (TMT), B-H Tracer, Four-point Probe, Hyperthermia System, Ferroelectric and Dielectric Testers, Teslameter, Anodizing/Electrodeposition power supplies, Spin coater, etc. Therefore, you may seek a purchase opportunity by contacting my email address: amirh.montazer@gmail.com. With regards.
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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 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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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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I don't fully understand your doubts. The TGA curve looks quite good. But it would make sense to look at TG, since drying is primarily mass loss, and the thermal effect is indirect effect. Also, the heating rate does not inspire absolute confidence. It is quite possible that significant overheating taken place (especially on such a large mass of the sample). Therefore, it is worth looking at the dependence of temperature on time.
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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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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..
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TGA curves show an increase in the thermal stability of the carrier nanoparticles after drug loading. What is the reason?
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Dear Rozita
Without knowing what NPs and kind of drug you are using it is not easy to answer your question. I guess that the loaded drug may have a kind of interaction with the NPS that stabilizes these NPs.
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Could anyone kindly provide the name of Institute/testing centre and contact details if any in India for TGA of Char in CO2 enviroment .
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Apart from IISc bangalore, Institute of chemical technology(ICT) Mumbai and National Chemical Laboratory (NCL) Pune also have the specified facility
Solid state and Structural Chemistry Unit, Indian Institute of Science, Bangalore
Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore
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TGA is used to study the thermal degradation of the polymer based inorganic hybrids, confirming the presence of metal oxides as residual mass. Is it possible to analyze these materials by GCMS to study the fragmentation pattern of the polymers (e.g. cellulose acetate, polyacrylic acid, polylactic acid etc)
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I think it's better to study DTA instate of the MS
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I have functionalized a material with an organic compound and performed different analyses such as TGA, XPS, elemental analysis (by EDS and varioMICRO) but I have a difficulty to determine the general formula. Is there any equation?
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Reconcile elemental analysis for all methods. Determine the mass average. Write a formula, such as water or hydrogen peroxide. You have determined 12% hydrogen and 88% oxygen. Write the unknown formula HxOy. Find the ratio x: y and, resulting in an integer ratio
12/1: 88/16 = 12: 5.5 = 2: 1. Hence, you have identified water, not hydrogen peroxide.
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If I have a complex connected with another ligand by a hydrogen bond with coordinated water from that complex; is this H-bond effect on the range of losing the coordinated water until 210 C because I have it? I need references, please.
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Dear dr.
I guess that the answer is not straightforward, first you have to detect the mechanism in each stage of TGA, find the first and second derivatives and try to obtain the product at 210C and do MS (mass Spectroscopy) and IR, i.e. Monitoring the product at different stages, but don't forget removing the water attached to the crystal surface by leaving the product 48hr in a 60C oven
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What is the relationship between onset temperature (determined from TGA weight loss curve) and Ea? Are they must be linearly proportional?
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Dear Bao,
there is not a direct relationship between the two parameters.
the Tonset or Tstart temperature refers to the start of thermal decomposition, on the other hand, Ea is a kinetic parameter which determines the energy that the reactants must have to transform into products (the energy barrier to be overcome).
isonconversal kinetic models are often used and recommended by ICTAC for solid thermal decomposition studies .
more information on this topic can bé found in our article "Synthesis of copper oxide nanoparticles and their catalytic effect on the thermal decomposition of ammonium perchlorate (ZAAC).
Regards
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Hello,
I would like to validate my regression algorithm which calculates activation energy and pre-exponential factor from the TGA curve. It uses integral method (the exponential integral for resolving the right side of the equation):
d_alfa/alfa = -A/beta*exp(-E/R*T)dT
where alfa is the extent of mass loss, beta - heating rate, A - pre-exponential factor, E - activation energy.
I compared my results with literature TG curves but, the results differ slightly. I'm wondering if the error is caused by my calculation algorithm or uncertainty of A and E estimation is so high.
Could anyone provide a simple TG curve (one component, first-order order kinetics) and corresponding A, E, and beta - I believe that the data calculated would be the best because I should receive exactly the same A,E result during regression using my algorithm.
Best regards,
Marcin Stec
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Marcin Stec Oh. I thought you know and it is clear from the picture.
This is great and almost simple to do with GraphPad Prism software.
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I need to compare the TGA patterns of two similar material. I have heard that comparison between the raw data is not correct! Could you please give me some suggestion to make them comparable?
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It is a bit late to answer Zille huma Malik . Just for other people looking for an answer. When you have TGA results of different materials and mass and looking for comparing them. Make sure you have a mass loss in percentage then it @should be all good.
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Hai all,
I need your advice regarding my TGA result. As you can see from picture below, the weight started to increase after being heated at high temperature of 500C. Fyi, I am using nitrogen atmosphere in TGA testing. Is it due to oxidation of iron? And is it possible for oxidation to occur even using nitrogen?
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Hi Rusila, on top of possiblity of iron been oxidised due to impurity of nitrogen, iron also could react with epdm when it decomposed to form iron carbide. I think both reaction happen. Metallic iron can react even with ppm order of oxygen and carbon species.
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Can someone help me to understand the two step degradation process of Methacrylate POSS in details. I have attached the TGA/DTG plot.
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Dear Dilli, in the first decomposition step you certainly observe the elimination of all eight methacrylate substituents (I assume that you talk about octasubstituted methacrylate POSS, right?). This could certainly occur through decarboxylation, i.e. elimination of CO2 and the propenyl substituents of the methacrylates in the form of C3 fragments. In the temperature range of ca. 500-700 °C the breakdown of the Si8O8 cage will occur. Did you check if the remaining mass corresponds to SiO2?
For a related study which includes TGA / DTG measurements please have a look at the following interesting article:
Synthesis, thermal stability and photoresponsive behaviors of azobenzene-tethered polyhedral oligomeric silsesquioxanes
Unfortunately this paper has not yet been posted as pubic full text on RG, but three of the authors have RG profiles. So there is a good chance that you can request the public full text directly from one of the authors via RG.
I hope this helps answering your question. Good luck with your work and best wishes, Frank Edelmann
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I am trying to clean the TGA crucibles that has adhesive (titanium-based) on it and operated at higher temperature of more than 1000 oC. This material is now stuck on the walls of the crucibles and sometimes it changes into some transparent form at the bottom of the crucible. Argon was used as input gas for analysis.
I have already done the following methods for this:
1. Sonication
2. Hot water treatment
3. Scraping of the material physically
4. Flame treatment
4. Acid treatment of H2SO4, and HCl (both for shorter and longer periods of time)
5. SC2 treatment (HCl + H2O2)
I also have aqua regia and piranha solutions in my mind but I did not try them yet. I am looking forward to any suggestions on this to easily remove that material. I would really appreciate your response.
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My experience shows that purification of aluminum oxide crucibles with acidic solutions quickly renders these unusable (they become brittle after 2-3 treatments and often change in weight during the experiment).
For cleaning I usually filled the crucible tightly with dispersed aluminum oxide, place it on aluminium oxide "pillow" and annealed these at a high temperature (for example 1200 C; heating and cooling are slow - for several hours). During annealing, the overwhelming amount of impurities goes into powder oxide. The crucible does not become completely clean, but it is quite suitable for "rough" experiments. For critical experiments, it is preferable to use a clean crucible.
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I have performed TGA of a metal oxide and have found that it is almost constant up to 750 °C i.e there is no weight loss. Therefore, on what parameter or basis its thermal stability can be explained?
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Dear all, usually a good approach via Ellingham diagram is followed to understand the order of stability of compounds including metal oxide. So simple search leads to how the diagram is constructed and used. My Regards
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I have a molded electrical connector. The density is 1.30 g/cc. In the air, the inorganic residue in TGA or ASH test is 12-14%. The FTIR of inorganic residue shows silica (SiO2). XRF analysis indicated a small amount of Na but mostly Al and Si. The FTIR of the composition (attached) indicated it to be PP-based and having Al2SiO3. The part burns very slow and self extinguishes, so perhaps it is V0 rated. FTIR does indicate it not it o be halogenated or with APP type FR additive. Further, the residue is not black char but white powder, So it is unlikely to be APP or other intumescent FR additives which leave black char.
Having a density of 1.30 for filled PP indicates a large amount of FR additive. Al2SiO3 leaves 60% inorganic, ATH 67%, Silicon rubber nearly 80%. The density of most of the inorganic oxides is 2.4-2.6. So for PP (density 0.905) to have a density of 1.30 requires composition to have a large amount of additive, but the TGA indicates much less presence.
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As Yonatan said, it is quite common to use talc for flame retarded PP. However, you indicated the XRF composition is Al and Si. Since talc contains a large amount of Mg, it is likely not talc. On the other hand, using about 15% char yield, the true density of the inorganic filler needs to be about 3.3-3.4 g/cc, which is possible among many silicate (high end) but very unlikely to be used as a flame retardant additive. An inorganic additive using a physical flame retardation mechanism, such as production of nonflammable gas, absorption of heat, and others, requires at least about 30wt% of additives. One seldom sees only 15wt% additive without chemical mechanisms, such as halogenated or phosphonate. A more likely scenario is that the filler may contain a volatile component, such as carbonate or hydrate, so that during the TGA analysis, those small molecules decompose and evaporate. Thus, despite adding, say 30-40%, the TGA analysis after heating to about 800-900oC leaves only the none-volatile component. This is consistent with the small char yield, but addition of relatively large fraction of inorganic component at the room temperature value.
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We have TA Instruments SDT Q600 and we connected vacuum pump to the furnace with the idea to make TGA/DSC experiments under vacuum conditions. Does anyone have experience with this setup?
I wonder, for atmospheric TGA, the calibration is well described in manuals. Is there something one needs to pay attention when calibrating under vacuum?
Lastly, for atmospheric TGA, one typically uses Calcium Oxalate to check on the performance of the TGA and DSC curves. What standard would one use under vacuum, or more precisely, is there some data that show calcium oxalate TGA+DSC under vacuum conditions?
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The first reasons which come to mind why a TG investigation is planned, are:
* to determine the stability and the content of the volatiles in a material;
* to study a material without interference of oxygen;
* to prepare an inert environment into which the active components of interest can be subsequently introduced.
With this diversity of possible applications, one cannot go much further with advice.
However, some precautions are likely to be of use:
* Even the highest vacuum is never free of molecules; actually, there are plenty of them. Achieving a non-oxidizing environment by evacuation is totally impossible due to the residual leaks and outgassing; the water vapor, always present in up to 500 layers of molecules on every practical surface, can oxidize even stronger than oxygen can. That includes the water vapor on the surfaces of the mechanism of the balance of the TG instrument.
Since the ideal vacuum is un-achievable, a more practical choice is admitting that fact, and working with an added residual bleeding of an inert gas trough the balance chamber, then through the area where the sample is. 1 Torr or a fraction of it can be much more stable in every respect than the "10-6" We need to remember that the vacuum gauge is measuring it's own environment, while the vacuum level at the other locations is anyone's guess.
* 1 ml of air weighs about 1000 micrograms, so evacuation of the moving parts of the balance plus the sample and its support produces a strong shift of the zero line. Still, some procedures allow achieving a ppm precision.
* Samples of the materials when thermally decomposing, produce condensable fumes which can destroy the TG instrument almost immediately.
And so on, and on, and on. A thermogravimetric experiment can produce rich information, but it requires a thorough preparation, to be meaningful. This is the area of conflicts between the user and the customer-support department of the instrument's manufacturer. They say: "The instrument seems to be working properly, as designed." - The user: "The instrument itself may work OK, but it does not work with my samples!" - "Sir, you certainly know much more about your materials than we possibly can; we are only responsible for the performance of the instrument." - "But I have paid so much money for the instrument to study my materials!" - "I recommend your checking Google if any other user had your problems." Please note this: "... your problems". No way around, TG researchers have to research how to use their instruments with their materials. They are never as straightforward as a tape measure.
In this respect the term "capibration" sounds to belong to the area of hopes.
If you are more specific about your experiments and measurements, a more focused help can be tried.
Jerry C.
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I want to know the effect of adding filler with polymer so I used thermal analysis TGA, DTG
which parameter more important in determining thermal stability between polymer and composite?
T onset
maximum temp of decomposition
weight loss percent
or all above
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Dear Eman Fahmy, you should specify wether it is an organic or an inorganic filler. The effect of inoganic minerals additives is more or less understandable. For example CaCO3 imparts additional thermal stability to many polymer such as PVC. The effect of fillers type and loading is much more seen if the mechanical properties are evaluated at different degrees of temperature. The changes is the stages of TGA thermograms also may be an indication when compared to the virgin unloaded matrix. My Regards
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I am analyzing ACC samples with TGA. From the recieved signal plot, there is a steep decline in measured weight loss and then decline rates becomes less. My question is to how to understand the initial decline rate is purley due to ACC dehydration? Is there a standarad that can be used for TGA ACC analysis that calibrates the reults (for example a fully dehydrated Calcite?)? or a blank test with TGA will be enough?
PS: TGA is having some steel sample for testing and calibration.
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Dear Amin Niamir,
I have attached one article which described the TGA analysis of Amorphous calcium carbonate (ACC). I hope it would be useful.
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I'm looking for an expert in master plot method in terms of biomass kinetic reaction mechanism.
I know which equation should I use, however my curves look totally different from these in other papers. I think, I do something wrong.
Can someone explain me step by step, what should I do to do this analysis? The best will be to show me that on one of my biomass TGA data. I can share these data.
regards
Tomasz
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You can use my software - thinks.chemphys.ru - to perform thiskind of analysis
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Would like to know how much oxazolidone is form and how much isocyanurate is formed, or are these two functionalities in the same material? percent conversion to oxazolidone?
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Thank you Ali. I am so sorry for not asking the right question. I was in a hurry and wanted to post question before I go on to other project. Actually Epoxy-isocyanate can have multiple reactions going on simultaneously. Depending on the amount of either epoxy or isocyanate, one reaction favors over other. So when I look at FTIR, I see peaks corresponding to oxazolidone, isocyanurate, if reaction is not complete isocyanate, and homo polymerization of epoxy, so I was asked by my researcher how many percent oxazolidone is formed? So question was regarding that. I have received a paper I requested from ResearchGate from Xavier Ramis and it has mentioned how to calculate. I am going to read carefully and try to learn . Thanks again.
I have used FTIR for quantitative analysis using a quant program in the past.
Thank you.
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I am trying to take the TGA data of my sample. However when I get data from instrument Shimadzu's TGA-50. The data is very noisy in the the instrument. The data is not uniformly degraded. How I can get smooth data without noise? Which parameters should be adjusted to collect uniformly degraded data. I have attached the TGA plot of my sample. Kindly suggest me any solution. I shall be thankful
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You should also consider decreasing the heat flow rate - increasing the measurement time (22 min for 570ºC)
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How to calculate Kinetic Parameters from (TGA,DSC,DTA,DTG) curve using Coats-Redfern?
I hope it will be a practical example with detailed steps, whether in Excel or Origin or any other program (entropy S, enthalpy H, G, A, K)
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A lot of information can be useful.
Best of luck
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During TGA analysis of the concrete sample, the weight loss (H2O, Ca(OH)2, and CaCO3) at different temperature range is observed.
How we can calculate the bound water loss from that analysis? Can anyone able to provide the example sheet of this bound water calculation analysis?
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As a suggestion, I can say that the different components in TGA analysis are eliminated at different temperatures. The mass release for water, Ca(OH)2 and CaCO3 will be different. Particularly, the attention in water should be centered around 100°C. In this case, you will see a peak around this temperature in the derivative of the mass loss. By knowing the amount of the sample used (in grams for example) and knowing the % change of the sample at his particular temperature, you can calculate how much water was released.
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I have a TGA curve which showed that my UiO-66 is completely converted to ZrO2 at around 530 degrees, I just need to know how to calculate the weight loss ratio.
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Vianney Andrew Yiga TG graph can be presnted as mass plotted against temperature or mass loss plotted agaainst temperature. If you plot mass vs. temperature, it starts from 100%. It, in fact, presents residual mass plotted against temperature. But if you really mean, mass loss, it should start from 0%. Please check my previous answer again carefully.
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I am using Vyazovkin's advanced isoconversional method to calculate the activation energies of the co-pyrolysis of biomass and waste tyre mixtures. The problem is that after calculating conversion, the resulting lines cross each other, when in theory they should meet only near conversion = 0 and conversion = 1. The end result is that I am getting negative activations energies, which don't make sense. I belive it might be due to errors during the thermogravimetric analyses, but I have been following the ICTAC recommendations and I don't know what else could be causing these issues. Any input is welcome! thank you in advance.
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You are welcome, I am glad to hear that you have solved the problem.
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I want to determine soil organic carbon using TGA. does anyone know the exact methodology, e.g. temperature, gas flow, ets..?
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Dear Nikou Hamzehpour,
I have attached two articles which TGA method of soil has been explained. I hope they would be useful.
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Target bacterial operon is reported to be co-transcribed and co-translated in wild type host. However, protein expression analysis (SDS PAGE) indicates translation of only first gene in frame with His tag.
Thankyou.
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@ Ana thankyou for your suggestion.
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In my TGA curves related to liquid polysulfide resin-clay nanocomposites, for neat LPS and LPS/CNPs 1% , a small peak can be seen in higher temperatures as in following fig.
what can be an acceptable explanation for this secondary small shoulder?
in other words, what process can suddenly increase the mass of the sample at the end of the process?
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Only an additional chemical reaction can cause this, for example, oxidation. So the experiment should be conducted in a nitrogen atmosphere. However, such a small peak is presumably an instrument error that the software did not compensate for.
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Hello all,
If we need to calculate the release% of a certain inhibitor we have the following formula:
Percentage release of inhibitor(%) = Mt/M0 × 100 %
where Mt represents the amount of the released inhibitor at the time of t, and M0 is
the total amount of inhibitor encapsulated inside the container.
How to get M0 from TGA results with a unit similar to Mt, while TGA results show loading of 18 wt.% of the inhibitor inside the container (Mt unit is µg/ml and is acquired from UV- spectroscopy and its standard curves)?
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You need the initial mass (m) of the sample which used for the TGA. Then:
Percentage release of inhibitor (%) =(Mt.V)/(m.w) × 100 %
where V (mL) is the volume of the release medium and w is the TGA weight loss percentage (here 0.18).
Also, denominator of the formula is the released amount in µg at time t and the numerator is the total amount of the inhibitor inside the container in µg.
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Hi,
Here I attached TGA test results of DGEBA based expoy.
What was the reason to have such a weight drop?
Thank you,
Janitha
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Dear Janitha,
There are two events occurring at 330.81 and 515.28 deg C.DGEBA is a symmetrical molecule and has high stability, but also it is an organic bulky molecule, hence the energy required to break DGEBA maybe substantially higher as compared to conventional organic compounds but also lower than inorganic substances. This means at 330.81deg C , there is a weight loss(probably due to cleaving and elimination at the phenylpropan2-yl region ) and the second event at 515.28 deg C because of elimination of the oxiran group.
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TGA shows solvate formation. DSC shows extra full endotherm of cocrystal.Does it seems polymorph? scxrd shows different cocrystal.
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TGA shows solvate formation-can be determined with 100% certainty subject to the users experiences and skills.
DSC shows extra full endotherm of cocrystal-cannot be as certain as that by TGA.
scxrd shows different cocrystal-different diffraction peaks can and can ONLY conclude a new physical form, which can, however, be a different polymorphic form, salt form, or cocrystal form, if applicable.
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I have performed TGA_DSC of cement paste with different clays. Samples 1-4 showed similar total weight loss and DSC curves, but samples 5 and 6 showed less weight loss.
As all the samples have similar compositions (determined from XRD), what could be the reason for different weight loss for samples 5 and 6?
For samples 1 to 4, 50 mg weight is used whereas for samples 5 & 6, 35 mg weight is used for doing TGA. Can this be a reason for the above change?
thanks
saurabh
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It is important to have a representative sample size when conducting TGA analysis of cementitious or other multi-phase materials. At NIST, we generally tried to use our large volume TGA pans and get a sample size close to or exceeding 100 mg.
Also, results often depend on from which temperature you are measuring your final weight loss. In your figure 7, one can observe that already by 100 C, when the sample should be losing mostly free water, samples 5 and 6 have much less mass loss than those of 1-4. Perhaps these samples were allowed to "dry out" more prior to being loaded into the DSC. You can try renormalizing your mass loss results using the 100 C masses of each specimen as the new basis. This should definitely get rid of some of the variability between specimens.
Regarding the heat flow plot, it would be better to plot the y-axis as heat flow per unit mass as otherwise it is difficult to compare the various curves.
From the mass loss curves, the mass loss between 400 C and 500 C is usually attributed to water lost from calcium hydroxide and while it is difficult to tell exactly from viewing the curves, the six specimens appear to have fairly similar absolute mass losses between 400 and 500 C. This would suggest that the free water loss (prior to 100 C) may indeed be biasing the subsequent cumulative mass loss curves and normalizing based on the mass measured at 100 C may be a good way to go.
Good luck,
Dale
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HDPE samples were aged at higher temperatures in the presence of water and CO2 than the TGA test was performed in Nitrogen? Weight gain is seen in the curve? What could be the possible reason for that?
Kindly see the curve in attached file.
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Aging under H2O or CO2 will end up with a material behavior below 120 C. To follow the behavior of a polymer, the changes in composition and structure may not exceed 400 C because the material is totally destroyed and only carbon may be left if any. Thus, listing examples occurring above 600 or 900 C is completely beyond the study of polymer decomposition. Regards
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Hello all,
I have a two graph ( TGA and DSC) of a biopolymer that I see decomposition starts around 170C. However once I run the DSC I do not see any melting or crystallization peak. Why?