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RE: [sdpd] Percentage crystallinity calculation using Powder XRD
The separation of x-ray scatteering patterns in to crystalline and
amorphous components to calculate a fraction of crystallinity is a
widespread practise in the study of semi-crystalline polymers. With such
materials the number of crystalline peaks in the region of Q 0.5 to 2/A
is usually small and often the basic form of the amorphous scattering
can be obtained by the study of a quenched or molten sample. Of course
at room temperature, the amorphous component will not be exactly the
same, but thye fully amorphous sample provides a good starting point in
terms of peak fitting. We usually equate the integrals of Q*Q*I(Q)
(conservation of intensity).
Geoffrey Mitchell
Geoffrey Mitchell
Professor of Polymer Physics
Director of the Centre for Advanced Microscopy
Department of Physics and Polymer Science Centre
University of Reading
Whiteknights, Reading RG6 6AF UK
Tel + 44 118 3788573 Fax + 44 118 9750203
Tel + 44 118 3788541 (Secretary)
www.reading.ac.uk/psc g.r.mitchell...@reading.ac.uk
www.reading.ac.uk/cfam www.reading.ac.uk/physics
-----Original Message-----
From: bixam manthri [mailto:mantri_21...@yahoo.com]
Sent: 17 February 2005 08:11
To: sdpd...@yahoogroups.com
Subject: Re: [sdpd] Percentage crystallinity calculation using Powder
XRD
Dear Sir,
Thanks for your reply,
Is there any method for the same without using any Internal reference
standerd.
Without establishing a calibration curve can we simply calculate the
percentage of cystallinity in a sample, having the diffractogram.
Physically can we do this??: calculating the Area of each individual
peaks seperately and the net area of the total diffractogram.
%crystallinity= 100* sum of area of each individual peak/ Net area of
the Diffractogram.
%crystallinity= 100* C/ A+C
where C= net area of crystaline peaks
A+C= Net area Of the Diffractogram.
Please confirm me how far this method is accepted.
Thanking you
Best Regards
Manthri.
Armel Le Bail <alb...@cristal.org> wrote:
>Iam an working on the percentage of crystallinity calculation using the
>powder XRD pattern. Could any one can give me some documentation or the
>reference information.
If you do not have access to the Web of Knowledge nor
direct access to other commercial systems, then try
the new Scholar Google search engine :
135 references obtained by a search with keywords "crystallinity
percentage X-ray":
http://scholar.google.com/scholar?hl=en&lr=&q=crystallinity+percentage+X
-ray&btnG=Search
Anyway, I am afraid that this kind of estimation needs
for a calibration curve established from well known mixtures
of crystalline and amorphous phases.
And the question is : is there really a clear separation between these
two parts when the crystalline part becomes highly defective ? So, be
prudent with your results...
Best wishes,
Armel
PS - Other search for references possible at :
INGENTA: http://www.ingentaconnect.com/
INIST : http://www.inist.fr/
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