Jon! Surprised you have not got inputs already on this extremely significant fundamental question. I'd suggest you spread the word by trying a few other topics as well. Once I touch the question, you'll see those that are connected with me do the same. RG is setup that way. I'd "poke" Matteo Leoni ("basturist") & Edward Payzant ("swordsman") with this notion as well, if I were you. Incidentally, I found you by a general search. I'll also post similar other RG discussions with significantly higher participation rate. Check out the topics they are listed under. That may be helpful to all the RG members reviewing this post.

1. When you are referring to many of these formulae you must bare in mind to compute the Integrated Intensity under each constituent phase in order to be precise. This is not a trivial task. You must correctly & precisely identify instrumental aberrations, back-ground signal, absorption effects, Compton effects, and many more. Besides, absent the 2D diffractogram, you only have a "partial idea" any way. Conventional 1D diffractograms (such as yours) are "blind" to any potential "preferred orientation".

2. You must identify your sample morphology or present photos (sample, XRD tool, beam conditioning, etc. details!) for the best advise from the highly competent and knowledgeable RG membership. Present all the facts simultaneously rather than piece meal. As you embellish the information base the precision of the answers from RG will be unequivocal. SEM, TEM and other literature about your material would be helpful. For example, I have no clue yet what "PLA" means for now. Once you express or I Google, I'll know.

3. Present a "known" standard diffractogram from the same XRD tool with identical conditions.

4. Use XRD for quantifying "relative quality" of Nano structure. Compare with internal or external standards. Learn about "convolutions"!

5. Master the classic book by Andre Guinier if you are serious about using advanced real time, in situ, NDE XRD techniques and tools tried and tested for nearly a century:

http://www.flickr.com/photos/85210325@N04/10515372183/lightbox/

Here is an example of the use of "known standard" and "relative analyses" with XRD:

http://www.flickr.com/photos/85210325@N04/10888339173/lightbox/

http://www.flickr.com/photos/85210325@N04/10885954484/

Jon! Your data! Here's approximately what you need to figure out numerically and do so with several calibration samples of known Nano structure

http://www.flickr.com/photos/85210325@N04/11228321453/

Please review contents of: https://www.researchgate.net/post/How_can_I_find_the_phases_corresponding_to_the_XRD_peaks_at_135_and_165_in_the_XRD_patterns_of_carbon_materials

Hi! Ravi! Thank you very much for your advices, i'll look at all of the stuff you have gently let me here :) (PLA =polylactic acid).

Anyway i have found a professor who is in my project who knows about this, my question was more based because i was thinking that somebody with no expererience on crystallinity of polymers was to make the XRD - so - i had to be ready for any question :)

Cheers! :) and thank you very much :)

Jon! Cool! What are the applications of PLA? What are your ultimate objectives for looking at this material with XRD?

Hi!

I have been continuing my experiments on crystallization :). I have been looking on the suggested topics and in the literature, and i have clear what i need to do but not how.

The PLA (poly lactic acid) is a biopolymer and i intend to use it on food packaging applications. Now im working with nanocomposites which among other stuff, they act as nucleating agent, this means that they enhance the crystallization of this polymer).

Now i have gone further on this research and i have followed the crystallizattion of those nanocomposites at different temperatures by XRD, (I have the XRD patter on PLA after 5 minutes at 140 C, after 10 minutes at 140 C .... and so on) and i would like to retrieve from my XRD data 2 things:

- the DC of crystallinity vs time to check it wiith the data of the DSC and MDSC. (i need a software that helps me calculating the area in the amorphous domain and the crystalline

- the spherulite size (i will need to use the schreer ecuation, i need a software to calculate the FWHL, this should be easy ... )

I just forgot .. i hope that my crystals will have micro size (around 10-60 microns) ... and although i have seen people making this on the literature im not completely sure if i can use scherrer equation for this ...

Hi all of them .. still struggling with tha XRD ... 

From Polarized Optical microscopy i have found that my PLA has a really non-homogeneous crystallinity, with this i mean that there is no homogeneous spherulite distribution within the matrix and that you can find spherulites ranging 1 micron to 60 microns. I guess that different spherulite size, could also lead to different lamela thickness, and now my question is ..

How much a broad lamella thickness distribution can affect the XRD pattern? I mean the braggs equation says that smaller the particle (lamella) broader the peak, so what I really fear is that im getting the peak thickness from "large" lamelas and a broad peak width coming from "small" lamella, hence having "false" results from XRD.

You may need to consider the use of transmission Laue technique to simultaneously monitor "preferred orientation" due to the presence of lamellar constituents.

"hence having "false" results from XRD" - Usually, it is not the results (observations) from XRD that are false, but their INTERPRETATIONS :-)

"FWHL", you mean FWHM?