I synthesized MWCNTs/M doped ZnO nanocomposites.Given that MWCNTs are functionalized with NH2.The nanocomposites were calcined at temperature range 300-500 C and then investigated by SEM. SEM images of calcined nanocomposites showed a difference in size and shape of MWCNTs in comparison with pristine one(without calcinations). What is the effect of temperature on the properties of MWCNTs.
Calcined at 300-500C for how much time?.. In case of Nh2-CNT, calcining at 500C will drive away much of N2 moieties.. so check FTIR.. Calcining ZnO/NCNT may 'unzip' CNT..
Dear colleague Hassan Alshamsi,
Have a nice time and good day, peace be up on you.
How you decide this temperature range (300-500)? do you have the DTA or DSC of MWCNTs? any how the effect pf temperature to be highly effective, the thermal stability of the materials should be follow (Tc-Tg); Tc is the crystallization temperature and Tg is the glass transition temperature, to get high temperature response the investigated temperature should be included through the range of (Tc-Tg) if not you will have no or low response. So firstly you need to know both Tg and Tc. You can get it using DTA or DSC, (see the attach file). Secondly decide the temperature range.
I wish this is useful and help you.
Your
A. El-Denglawey
Dear colleague Hassan Alshamsi,
Have a nice time and good day, peace be up on you.
1- The annealing temperature is a function of substrate type, ambient of vacuum, properties of material (physical and chemical). structural form of the materials( amorphous, poly crystalline and crystalline). etc. the annealing may develop the properties of material or vice versa depending on the mentioned parameters.
2- The annealing temperature may reduces the presence of imperfections, defects or localized states. So the annealing may develop the structural properties of material; more order and arrangement are available consequently the small particle size my be joined or agglomerate to produce larger one with different sizes and different shapes. The growing process of particle size due to annealing may has different orientations. Also annealing may has a negative effect on the structural properties of material such this issue is accompanied by the decreasing of XRD intensity and the increasing of FWHM.
The two mentioned issues are the available effect of annealing temperature, you can compare to MWCNTs.
I wish this is useful and help you.
Your
A. El-Denglawey
Dear Dr.Hassan Alshamsi , the temperature effect the average grain size .
Hassan.. to get the right answer for your question we need to know the bonding type of the NH2 group. A purely inorganic system like the MWCNT doped with ZnO may not retain NH2 unless you used special introduction route. There is no possible bonding between ZnO and NH2 because they are both of basic reactivity. IR spectrum my give some confirmation about the nature of the bonding by focusing on the 3200-3350 cm-1 signals. Calcination is a tough treatment that may result in the loss of NH3 or perhaps NH2-NH2. Any further information may help us to find the most relevant answer.... Good luck.
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