I have fabricated a composite comprising of High density Polyethylene (HDPE) and Polypropylene (PP). I have verified the non compatibility of the polymers by FTIR , XRD and DSC tests. But I have captured few images of the composite surface by scanning electron microscope (SEM). Is it possible to differentiate the surfaces and distinguish both the phases through SEM images. I am not finding any clue to differentiate the phases through SEM test. Please help.
As both are polymers , so its difficult to distinguish phase. You first take SEM image of pure HDPE and PP and both will show single phase and compare it to composite. The PP-HDPE composite should show phase separation. Either PP or HDPE will have continous phase depends on quantity. If PP is more then it will show continuous phase and HDPE will show disperse phase. If HDPE is more then it will show continuous phase and PP will show disperse phase.
HDPE and PP are incompatible, but I think there will be significant diffusion of phase upon mixing within film formation.
If phase segregation is visible in SEM, Zonal elemental mapping (EDAX) could help in identification of elements not phases.
You can do either line/ zonal mapping to locate the elemental distribution.
Other option I wonder could be to use Tracer in any one polymer matrix
@Madhumita Mukhopadhyay
Both polymers consist of C and H, so no help from EDS (or, as you called it, EDAX).
@ Harekrushna Sutar
There are some stains for polymers, mostly used for TEM but they could be useful and for SEM, such as OsO4 (toxic!). You may want to observe cross section, because surface of specimen can contain just one of your polymers.
@Vladimir Dusevich
Can phases be differentiated from cross section.
I do not have experience with polymer/polymer composite, but for glass/polymer composite outer surface (of specimen made in mold) may completely consist of polymer, no glass (glass is encapsulated in polymer).
But then, how are you confirming about their incompatibility.. are they incompatible in all temperature, pressure regims?
Consult phase diagram,, if found... then the specific region of compatibility can also be judged..
Incompatible signifies non formation of new component as verified by FTIR, XRD and DSC tests. But the region of non compatibility in terms of pressure and temperature is unknown. Up to 200 degree centigrade the DSC tests verify the non compatibility of both the polymers. But at high pressure it is unknown to me.
If your samples have a pretty smooth surface, it is possible to use an AFM in tapping mode with phase contrast.
Article Mapping Polymer Heterogeneity Using Atomic Force Microscopy ...
Good luck!
@Denis Korneev
Your answer is appreciable. I will proceed with your suggestions. Thank you.
Hi, once I worked on composites of polymer blend. For the SEM analysis of PP and HDPE blend, make a solution blending of PP and HDPE in Xylene or Toluene solution at 120oC. When the polymers become completely miscible, pour in a glass petri disc and let it to dry in oven. After drying, use the blend for SEM analysis. You can see the one polymer form granules over other polymer. As per my knowledge, you will see PP granules on HDPE continues matrix. For reference SEM image, check the file attached..Good luck
YOU MAY also study the samples under TEM. I think you may easily get to differentiate shades based on the densities of the individual polymers. You may also select different spots/area for SAAD analysis, it will be an interesting study. I dont have much knowledge in polymers, but if the C and H percentages are different in both you may go for EDAX attached with TEM.
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