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Stribeck N, Schneider K, Zeinolebadi A, Li X, Sanporean CG, Vuluga Z, Iancu S, Duldner M, Santoro G, Roth SV. Studying nanostructure gradients in injection-molded polypropylene/montmorillonite composites by microbeam small-angle x-ray scattering. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2014; 15:015004. [PMID: 27877646 PMCID: PMC5090607 DOI: 10.1088/1468-6996/15/1/015004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/17/2014] [Accepted: 12/24/2013] [Indexed: 06/06/2023]
Abstract
The core-shell structure in oriented cylindrical rods of polypropylene (PP) and nanoclay composites (NCs) from PP and montmorillonite (MMT) is studied by microbeam small-angle x-ray scattering (SAXS). The structure of neat PP is almost homogeneous across the rod showing regular semicrystalline stacks. In the NCs the discrete SAXS of arranged crystalline PP domains is limited to a skin zone of 300 μm thickness. Even there only frozen-in primary lamellae are detected. The core of the NCs is dominated by diffuse scattering from crystalline domains placed at random. The SAXS of the MMT flakes exhibits a complex skin-core gradient. Both the direction of the symmetry axis and the apparent perfection of flake-orientation are varying. Thus there is no local fiber symmetry, and the structure gradient cannot be reconstructed from a scan across the full rod. To overcome the problem the rods are machined. Scans across the residual webs are performed. For the first time webs have been carved out in two principal directions. Comparison of the corresponding two sets of SAXS patterns demonstrates the complexity of the MMT orientation. Close to the surface (< 1 mm) the flakes cling to the wall. The variation of the orientation distribution widths indicates the presence of both MMT flakes and grains. The grains have not been oriented in the flowing melt. An empirical equation is presented which describes the variation from skin to core of one component of the inclination angle of flake-shaped phyllosilicate filler particles.
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Affiliation(s)
- Norbert Stribeck
- Department of Chemistry, Institute TMC, University of Hamburg, Bundesstrasse 45, D-20146, Hamburg, Germany
| | - Konrad Schneider
- Leibniz-Institut für Polymerforschung (IPF), D-01069, Dresden, Germany
| | | | - Xuke Li
- Department of Chemistry, Institute TMC, University of Hamburg, Bundesstrasse 45, D-20146, Hamburg, Germany
| | - Catalina-Gabriela Sanporean
- Department of Mechanical and Manufacturing Engineering, Aalborg University, Fibigerstræde 16, DK-9220, Aalborg, Denmark
| | - Zina Vuluga
- National Research and Development Institute of Chemistry and Petrochemistry ICECHIM, Splaiul Independentei 202, Bucharest, Romania
| | - Stela Iancu
- National Research and Development Institute of Chemistry and Petrochemistry ICECHIM, Splaiul Independentei 202, Bucharest, Romania
| | - Monica Duldner
- National Research and Development Institute of Chemistry and Petrochemistry ICECHIM, Splaiul Independentei 202, Bucharest, Romania
| | | | - Stephan V Roth
- HASYLAB at DESY, Notkestraße 85, D-22603, Hamburg, Germany
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Oliveira RP, Driemeier C. CRAFS: a model to analyze two-dimensional X-ray diffraction patterns of plant cellulose. J Appl Crystallogr 2013. [DOI: 10.1107/s0021889813014805] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Cellulose from higher plants is a vast renewable resource organized as crystals. Analysis of these crystals by X-ray diffraction poses very specific challenges, including ubiquitous crystallite texture and substantial overlapping of diffraction peaks. In this article, a tailor-made model named Cellulose Rietveld Analysis for Fine Structure (CRAFS) is developed to analyze two-dimensional X-ray diffraction patterns from raw and processed plant cellulose. One-dimensional powder diffractograms are analyzable as a particular case. The CRAFS model considers cellulose Iβ crystal structure, fibrillar crystal shape, paracrystalline peak broadening, pseudo-Voigt peak profiles, harmonic crystallite orientation distribution function and diffraction in fiber geometry. Formulated on the basis of the Rietveld method, CRAFS is presently written in the MATLAB computing language. A set of meaningful coefficients are output from each analyzed pattern. To exemplify model applicability, representative samples are analyzed, bringing some general insights and evidencing the model's potential for systematic parameterization of the fine structure of raw and processed plant celluloses.
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Diddens I, Murphy B, Krisch M, Müller M. Anisotropic Elastic Properties of Cellulose Measured Using Inelastic X-ray Scattering. Macromolecules 2008. [DOI: 10.1021/ma801796u] [Citation(s) in RCA: 183] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Imke Diddens
- Institut für Experimentelle and Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany, and European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - Bridget Murphy
- Institut für Experimentelle and Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany, and European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - Michael Krisch
- Institut für Experimentelle and Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany, and European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - Martin Müller
- Institut für Experimentelle and Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany, and European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
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Stribeck N, Nöchel U, Fakirov S, Feldkamp J, Schroer C, Timmann A, Kuhlmann M. SAXS-Fiber Computer Tomography. Method Enhancement and Analysis of Microfibrillar-Reinforced Composite Precursors from PEBA and PET. Macromolecules 2008. [DOI: 10.1021/ma8015322] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Norbert Stribeck
- Department of Chemistry, Institute of Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany; Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand; Institute of Structure Physics, Technical University of Dresden, 01062 Dresden, Germany; and HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
| | - Ulrich Nöchel
- Department of Chemistry, Institute of Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany; Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand; Institute of Structure Physics, Technical University of Dresden, 01062 Dresden, Germany; and HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
| | - Stoyko Fakirov
- Department of Chemistry, Institute of Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany; Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand; Institute of Structure Physics, Technical University of Dresden, 01062 Dresden, Germany; and HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
| | - Jan Feldkamp
- Department of Chemistry, Institute of Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany; Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand; Institute of Structure Physics, Technical University of Dresden, 01062 Dresden, Germany; and HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
| | - Christian Schroer
- Department of Chemistry, Institute of Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany; Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand; Institute of Structure Physics, Technical University of Dresden, 01062 Dresden, Germany; and HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
| | - Andreas Timmann
- Department of Chemistry, Institute of Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany; Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand; Institute of Structure Physics, Technical University of Dresden, 01062 Dresden, Germany; and HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
| | - Marion Kuhlmann
- Department of Chemistry, Institute of Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany; Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand; Institute of Structure Physics, Technical University of Dresden, 01062 Dresden, Germany; and HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany
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Sturcová A, Davies GR, Eichhorn SJ. Elastic modulus and stress-transfer properties of tunicate cellulose whiskers. Biomacromolecules 2005; 6:1055-61. [PMID: 15762678 DOI: 10.1021/bm049291k] [Citation(s) in RCA: 424] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Experimental deformation micromechanics of natural cellulose fibers using Raman spectroscopy and X-ray diffraction have been widely reported. However, little has been published on the direct measurements of the mechanical properties, and in particular the elastic modulus, of the highly crystalline material in the native state. Here we report on measurements of the elastic modulus of tunicate cellulose using a Raman spectroscopic technique. A dispersed sample of the material is deformed using a four-point bending test, and a shift in a characteristic Raman band (located at 1095 cm(-1)) is used as an indication of the stress in the material. Relatively little intensity change of the Raman band located at 1095 cm(-1) is shown to occur for samples oriented parallel and perpendicular to the polarization direction of the laser, as compared to a highly oriented flax sample. This indicates that the tunicate sample is a two-dimensional in-plane random network of fibers. By use of this result, the Raman shift, and calibrations with strain from other materials, it is shown that the modulus of the material is very high, at about 143 GPa, and a lack of Raman band broadening is thought to be due to the fact that there is pure crystalline deformation occurring without the effect of crystalline/amorphous fractions. A strain sensitivity of the shift in the 1095-cm(-1) Raman peak for this specimen is shown to be -2.4 +/- 0.2 cm(-1)/%. A molecular mechanics approach, using computer simulation and an empirical force field, was used to predict the modulus of a highly oriented chain of the material, and this is found to be 145 GPa, which is in agreement with the experimental data. However, by use of a normal-mode analysis, it is found that a number of modes have positions close to the central positions of the experimental Raman band. One in particular is found to shift at a rate of 2.5 cm(-1)/%, but due to the complex nature of the structure, it is not entirely conclusive that this band is representative of the experimental findings.
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Affiliation(s)
- Adriana Sturcová
- Materials Science Centre, School of Materials, University of Manchester, Grosvenor Street, Manchester, M1 7HS United Kingdom
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