Why the percentage enhancement of tensile strength, young's modulus and elongation doesn't match with each other in case of nanocomposites for a particular wt percentage?
Their mechanical properties depend on several parameters, like filler amount (%), nature and shape of nanofillers, Another important parameter is the interface between the filler and matrix (polymer). This parameter plays a crucial role since the applied tensile stress has to pass through the fillers (who have in most of the case, better mechanical properties), i.e. the matrix has to transfer the stress to fillers. In the literature of last decade, you can find several exemples of filler/matrix, where the surface of the filler is modified for improving the filler-matrix interactions.
In the case of nanocomposites several models have been proposed in order to predict their mechanical behaviour.
For a particular filler % say, 2 wt. % of MWCNTs reinforcement enhances the mechanical properties. Now the question is why the % enhancement of tensile strength, Flexural strength, Young's modulus, Flexural modulus and elongation in 2 wt. % nanocomposites doesn't be same when the same processing method is followed?
hello，you can refer "Reinforcement of transparent poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by incorporationof functionalized carbon nanotubes as a novel bionanocomposite for food packaging"
I'm not really sure I got your explanation. I seems to me that you've reached a plateau where a range of nano-additive gives you the same properties. Can you attach some graph?
From what you said, I think that you mean why by the addition of nano particles, different mechanical properties changed differently and they were not enhanced/suppressed at the same extent !!!
This is due to the fact that each of those mechanical properties depend on different variables (mechanisms) and that's why when the mechanical properties are reported, they report different properties and different test results.
For example, Young modulus shows the resistance of the material against deformation at low strains; tensile strength is a measure of how much stress the material can withstand; Elongation at break shows the maximum strain that the material can withstand and ...
So, Although you can discuss about how solid inclusions affected those properties, you should not be concerned about the differences in their enhancement/suppression.
The most imprtant thing i would like to know is weather you are asking the % enhances of nanocomposites with difference % of additives but with same bulk phase? or you asking changes in mechanical with different % of additives in different bulk phases/ If your answer in second, i would suggest you to go back start looking at the basics of mechanical properties and you will realize their definition to a constant physical composition. any chances in the composition with cause a change in all the mechanical properties with varying percentages.
But if you issue is he first one, then i hope i can shed some light on the topic.
I guess you are not considering the effective dispersion on the filler materials. Ideally we would like the additives to disperse and form a lattice structure i.e uniform spacing between two additives. realistically it is not going to happen cos there is substantial amount of particle-particle interaction, spacing between particles, formation small and large aggregates (trust me , they do form) and occurrence of such aggregates, interaction between bulk phase and additive are few of many parameter which dictates the changes in the mechanical properties.
Also, i wouldn't be judicious to club all the mechanical tests under a single umbrella. Of the modes you have listed i.e tensile, compression, flexural etc etc, if you read in detail you would realize the stress distribution maps of every mode is very difference.
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