(PDF-2 Release 2015, PDF-4+ 2015, PDF-4/Organics 2016)
Chitin - polyglucosamine, PDF 00-065-0890
Polyglucosamine (L-poly-chitin), PDF 00-065-0890, raw data PD3 XRD pattern with d-spacing, intensity overlay (top) and simulated XRD two-dimensional ring pattern (bottom). Data provided by J. Deschamps, Naval Research Laboratory: Deschamps, J. “Characterization of chitin preparations using powder and film X-ray diffraction methods,” Powder Diffr. 28, 44 (2013).
New Capabilities: Crystallinity and crystallite size measurements
Polymers often can pose a challenge for XRPD investigations. Variations in macromolecule chain length, the occurrence of chain branching, and processing conditions often results in polymer materials that can be amorphous, semi-crystalline, highly crystalline, randomly oriented, or preferentially oriented. In commercial applications, many composites are comprised of a polymer base with inorganic or organic additives present. Inclusion of raw data XRPD patterns for polymers in the PDF database, starting in Release 2009, provides a more complete picture to help identify crystalline and amorphous components of a polymer XRPD pattern. The original discussion of including full pattern polymer data in the PDF began with an International Centre for Diffraction Data (ICDD) task group member. It is now a reality with 125 polymer raw data XRPD patterns in the PDF, focusing on high volume commercial polymers. This includes 24 new patterns added to the 2015 product line release.