X-ray Diffraction Analysis of Polymers Expanding Materials Characterization Capabilities Using the ICDD Powder Diffraction File TM

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1 X-ray Diffraction Analysis of Polymers Expanding Materials Characterization Capabilities Using the ICDD Powder Diffraction File TM Tom Blanton Stacy Gates, Soorya Kabekkodu, Justin Blanton, Cyrus Crowder and Tim Fawcett, International Centre for Diffraction Data (ICDD), Newtown Square, PA International Center for Diffraction Data

2 Polymer analysis using XRD Many techniques are used for polymer characterization IR, NMR, GC/MS, Raman, etc. Why use XRD? Polymers can have amorphous and crystalline regions Crystallite size is small and measurable by XRD Polymers are often used as the base component in composite materials

3 Searching for polymer entries in PDF-4+

4 Polymer entries in PDF-4+ Release 2014

5 First polymer entry in the ASTM/JCPDS/ICDD Powder Diffraction File Simulated XRD pattern

6 Polymer order: chemistry matters Highly crystalline - Teflon Semi crystalline polyethylene terephthalate Micro crystalline cellulose 1β Amorphous - polycarbonate

7 Polymer microstructure: all about the processing Melt,quench polyethylene terephthalate (PET) Amorphous PET ε Thermally crystallized PET Strain crystallized PET

8 Nonwoven fabrics: spunbond polypropylene with additive Backscattered SEM

9 XRD pattern for spunbond fabric composite M

10 Phase ID using the PDF: CaO exposed to ambient air

11 Phase ID using the PDF: CaO exposed to ambient air

12 RIR quantitative analysis using the PDF

13 XRD analysis of polyvinyl chloride (PVC) polymer Unit cell from fiber patterns

14 PVC XRD powder patterns calculated vs. observed Adjust crystallite size to 50Å Commercial PVC sample You need the raw data to correctly define the XRD pattern

15 Raw data patterns in the PDF

16 Raw data (PD3) in the today s PDF

17 Polymer PD3 entries in PDF-4+ Release 2014

18 Polymer PD3 entries in PDF-4+ Release 2014

19 Polymer PD3 entries in PDF-4+ Release 2014

20 PDF3 data for Kapton film two different data collection geometries Reflection mode Transmission mode

21 Name search in the PDF

22 PEN example

23 The problem with using only d and I data for polymer analysis poly(ethylene-2,6-naphthalate)

24 Simulated XRD pattern for α-pen using only d and I data poly(ethylene-2,6-naphthalate) Default Pseudo-Voigt profile parameters

25 Simulated vs. raw data XRD patterns for thermally crystallized α-pen poly(ethylene-2,6-naphthalate)

26 Simulated vs. raw data XRD patterns for α-pen poly(ethylene-2,6-naphthalate) Crystallite size simulation 65Å

27 If we only had an amorphous reference pattern for α-pen! poly(ethylene-2,6-naphthalate)

28 Simulated from d,i list vs. raw data XRD patterns for amorphous α-pen poly(ethylene-2,6-naphthalate) Crystallite size simulation 8Å

29 (Amor. + Sim.) vs. raw data XRD patterns for α-pen 75% crystalline, 65Å 25% amorphous PD3 raw data

30 Effect of processing on α-pen

31 Are they really the same PEN phase? Thermal crystallization Strain crystallization

32 Are they really the same PEN phase? Crystallite size simulation 65Å

33 Are they really the same PEN phase? 65Å crystallite size (-110) preferred orientation From semi crystalline d and I pattern Raw data

34 PD3 raw data pattern for PDF entry , biaxially oriented α-pen

35 Similarity Index Can compare a raw data pattern to patterns in the PDF Especially useful when the sample contains amorphous or semicrystalline polymers

36 Similarity Index

37 Similarity Index Use Sieve, another SM program, or your knowledge for inorganic phase identification Use similarity index to confirm polymer identification

38 Rietveld refinement of Cellulose II with Si internal standard a = 8.076(13) Å b = 9.144(10) Å c = ) Å γ = (8) V = 683.5(18) Å 3 S.G. P112 1 R wp = χ 2 = Observed (with a Si internal standard), calculated, and difference patterns from the Rietveld refinement used to determine the lattice parameters of cellulose II. The red crosses represent the observed data points, the green line through them the calculated pattern, with the magenta difference plotted below. Blanton, Kaduk, Johnson, Powd. Diff., 29(2), 2014,

39 PDF-4+ Cellulose II PDF features Electron diffraction pattern Electron backscatter pattern Ring pattern Bond lengths/angles Simulated profile 3D structure Raw diffraction data PD3

40 Bragg Brentano reflection mode XRD patterns - effect of processing on Polypropylene Cast No heatset No stretch Heatset 120 C, 10s No stretch Heatset 6X Uniax stretch

41 2-D Transmission XRD patterns effect of processing on Polypropylene Cast No heatset No stretch Heatset 120 ºC, 10s No stretch Heatset 6X Uniax stretch

42 XRD data for polyvinylidene fluoride (PVF2) α-pvf 2 (random) γ-pvf 2 (random) β-pvf 2 (random) β-pvf 2 (uniax oriented) All have an amorphous component present

43 Ring patterns

44 β PVF2 2D XRD pattern PDF Ring pattern for β PVF2

45 Summary The ICDD Powder Diffraction File is the source for phase identification Beyond phase ID, the PDF provides property data that allows for a more complete characterization of a material and a better understanding of material properties Polymer PD3 data continue to be added the PDF helping the analyst get the right answer when analyzing materials 44 new PD3 polymer patterns will be included in PDF-4+ Release 2014

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