| 1. |
- Björn, Linnea, 1994, et al.
(författare)
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Scanning Small-Angle X-ray Scattering of Injection-Molded Polymers: Anisotropic Structure and Mechanical Properties of Low-Density Polyethylene
- 2023
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Ingår i: ACS Applied Polymer Materials. - 2637-6105. ; 5:8, s. 6429-6440
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Tidskriftsartikel (refereegranskat)abstract
- Injection molding is known to create a layered anisotropicmorphologyacross the sample thickness due to varying shear and cooling ratesduring the manufacturing process. In this study, scanning small-angleX-ray scattering was used to visualize and quantify the distributionof hierarchical structures present in injection-molded parts of low-densitypolyethylene (LDPE) with varying viscosities. By combining scatteringdata with results from injection molding simulations and tensile testing,we find that oriented shish-kebab structures, as well as elongatedspherulite structures consisting of semicrystalline ellipsoids, contributeto high ultimate tensile strength along the flow direction. Furthermore,we show that a higher degree of orientation is found close to theinjection gate and in LDPE with higher viscosity, consequently fromelevated shear and cooling rates present during the injection moldingprocess.
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| 2. |
- Casanova, Elisa A., et al.
(författare)
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SAXS imaging reveals optimized osseointegration properties of bioengineered oriented 3D-PLGA/aCaP scaffolds in a critical size bone defect model
- 2023
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 294
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Tidskriftsartikel (refereegranskat)abstract
- Healing large bone defects remains challenging in orthopedic surgery and is often associated with poor outcomes and complications. A major issue with bioengineered constructs is achieving a continuous interface between host bone and graft to enhance biological processes and mechanical stability. In this study, we have developed a new bioengineering strategy to produce oriented biocompatible 3D PLGA/aCaP nanocomposites with enhanced osseointegration. Decellularized scaffolds -containing only extracellular matrix- or scaffolds seeded with adipose-derived mesenchymal stromal cells were tested in a mouse model for critical size bone defects. In parallel to micro-CT analysis, SAXS tensor tomography and 2D scanning SAXS were employed to determine the 3D arrangement and nanostructure within the critical-sized bone. Both newly developed scaffold types, seeded with cells or decellularized, showed high osseointegration, higher bone quality, increased alignment of collagen fibers and optimal alignment and size of hydroxyapatite minerals.
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| 3. |
- Lo Re, Giada, 1971, et al.
(författare)
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Melt processable cellulose fibres engineered for replacing oil-based thermoplastics
- 2023
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 458
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Tidskriftsartikel (refereegranskat)abstract
- If cellulosic materials are to replace materials derived from non-renewable resources, it is necessary to overcome intrinsic limitations such as fragility, permeability to gases, susceptibility to water vapour and poor three-dimensional shaping. Novel properties or the enhancement of existing properties are required to expand the applications of cellulosic materials and will create new market opportunities. Here we have overcome the well-known restrictions that impede melt-processing of high cellulose content composites. Cellulose fibres, partially derivatised to dialcohol cellulose, have been used to manufacture three-dimensional high-density materials by conventional melt processing techniques, with or without the addition of a thermoplastic polymer. This work demonstrates the use of melt processable chemically modified cellulose fibres in the preparation of a new generation of highly sustainable materials with tuneable properties that can be tailored for specific applications requiring complex three-dimensional parts.
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| 4. |
- Nielsen, Leonard, 1992, et al.
(författare)
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Small-angle scattering tensor tomography algorithm for robust reconstruction of complex textures
- 2023
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Ingår i: Acta Crystallographica Section A: Foundations and Advances. - 2053-2733. ; 79:Pt 6, s. 515-526
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Tidskriftsartikel (refereegranskat)abstract
- The development of small-angle scattering tensor tomography has enabled the study of anisotropic nanostructures in a volume-resolved manner. It is of great value to have reconstruction methods that can handle many different nanostructural symmetries. For such a method to be employed by researchers from a wide range of backgrounds, it is crucial that its reliance on prior knowledge about the system is minimized, and that it is robust under various conditions. Here, a method is presented that employs band-limited spherical functions to enable the reconstruction of reciprocal-space maps of a wide variety of nanostructures. This method has been thoroughly tested and compared with existing methods in its ability to retrieve known reciprocal-space maps, as well as its robustness to changes in initial conditions, using both simulations and experimental data. It has also been evaluated for its computational performance. The anchoring of this method in a framework of integral geometry and linear algebra highlights its possibilities and limitations.
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