Crystallographic texture evolution in ultra high molecular weight polyethylene during uniaxial tension

Movva, Sahitya; Burrell, Reeshemah K.; Pooyan, Parisa; Garmestani, Hamid; Jacob, Karl I.

doi:10.1016/j.polymer.2022.124649

Cited by 4 publications

(7 citation statements)

References 27 publications

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“…The ODF of the samples’ crystallites gives more quantitative insights into the effect of texture. It is defined as the volume fraction of crystallites having a specific orientation ( g ) with respect to the sample coordinate system and it is the rotation required for the sample coordinate system [extension direction/rolling direction (ED/RD or x -axis), transverse direction (TD or y -axis) and normal direction (ND or z -axis)] to coincide with the crystal coordinate system . Bunge’s notation of ϕ 1 Φϕ 2 has been used throughout this study.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…There have also been studies that confirm the presence of shish kebab structures of UHMWPE fibers prepared by gel spinning − and the formation of shish-kebab structure of UHMWPE during injection molding of UHMWPE/HDPE blends as well as effect of change in UHMWPE molecular weight when melt blended with HDPE . Our previous work investigated crystallographic orientation or texture evolution in UHMWPE during uniaxial tension . For polymer products, texture plays a major role in determining the properties of the product for specific end uses.…”

Section: Introductionmentioning

confidence: 99%

“…The lamellar crystals are further oriented under a shear flow in extrusion, giving rise to additional crystalline orientation that can be studied using scattering or diffraction techniques. Depending on the method of processing the polymer undergoes, the size, the number of crystallites present, and their orientation can vary, affecting the resultant structural architecture and properties . It has been established that when both UHMWPE and HDPE are present together, their molecular chains can affect each other during the structure evolution resulting in improved overall structure of the blends. , It has also been reported that UHMWPE chains become more easily disentangled when blended with HDPE in melt processing, and also the HDPE addition enhanced the mobility and crystal structure of UHMWPE significantly. − In HDPE/UHMWPE blends, it has been reported that the crystallization of UHMWPE could induce the crystallization of HDPE at higher temperatures resulting in lower crystallization rates of the blends than those of their neat components .…”

Section: Introductionmentioning

confidence: 99%

“…Understanding the evolution of microstructure and the resultant texture, defined as the preferred alignment of crystallographic orientations in a polycrystalline medium, has been of great interest among the materials community. ,− , Additive manufacturing techniques, especially fused filament fabrication (FFF), also known as fused deposition modeling (FDM), an extrusion-based 3D printing technique, has shown to be very promising to fabricate sustainable customized complex materials. , 3D printing is more customizable and less expensive compared to injection molding. It is also possible to have better control of the process through its parameters like 3D printing speed, orientation, and temperature, thereby obtaining better control of microstructure and hence the resultant properties …”

Section: Introductionmentioning

confidence: 99%

“…Depending on the method of processing the polymer undergoes, the size, the number of crystallites present, and their orientation can vary, affecting the resultant structural architecture and properties. 8 It has been established that when both UHMWPE and HDPE are present together, their molecular chains can affect each other during the structure evolution resulting in improved overall structure of the blends. 9 , 10 It has also been reported that UHMWPE chains become more easily disentangled when blended with HDPE in melt processing, and also the HDPE addition enhanced the mobility and crystal structure of UHMWPE significantly.…”

Section: Introductionmentioning

confidence: 99%

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Crystallographic Texture Evolution in 3D Printed Polyethylene Reactor Blends

Movva,

Schirmeister,

Hees

et al. 2024

ACS Omega

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In this work, crystallographic texture evolution in 3D printed trimodal polyethylene (PE) blends and high-density PE (HDPE) benchmark material were investigated to quantify the resulting material anisotropy, and the results were compared to materials made from conventional injection molded (IM) samples. Trimodal PE reactor blends consisting of HDPE, ultrahigh molecular weight PE (UHMWPE), and HDPE_wax have been used for 3D printing and injection molding. Changes in the preferred orientation and distribution of crystallites, i.e., texture evolution, were quantified utilizing the wide angle X-ray diffraction through pole figures and orientation distribution functions (ODFs) for 3D printed and IM samples. Since the change in weight-average molecular weight (M w ) of the blend was expected to significantly affect the resulting crystallinity and orientation, the overall M w of the trimodal PE blend was varied while keeping the UHMWPE component weight fraction to 10% in the blend. The resulting texture was analyzed by varying the overall M w of the trimodal blend and the process parameters in 3D printing and compared to the texture of conventional IM samples. The printing speed and orientation (defined with respect to the axis along the length of the samples) were used as the variable process parameters for 3D printing. The degree of anisotropy increases with an increase in the nonuniform distribution of intensities in pole figures and ODFs. All the highest intensity major texture components in IM and 3D printed samples (0°printing orientation) of reactor blends are observed to have crystals oriented in [001] or [001̅ ]. Overall, for the same throughput, 3D printed samples in the 0°orientation showed greater texture evolution and higher anisotropy compared to IM samples. Most notably, an increase in 3D printing speed increased the crystalline distribution closer to the 0°direction, increasing the anisotropy, while deviation from this printing orientation reduced crystalline distribution closer to the 0°direction, thus increasing isotropy. This demonstrates that tailoring material properties in specific directions can be achieved more effectively with 3D printing than with the injection molding process. Change in the overall M w of the trimodal PE blend changed the preferential orientation distribution of the crystal planes to some degree. However, the degree of anisotropy remained the same in almost all cases, indicating that the effect of molecular weight distribution is not as significant as the printing speed and printing orientation in tailoring the resulting properties. The 3D printing process parameters (speed and orientation) were shown to have more influence on the texture than the material parameters associated with the blend.

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Section: Experimental Methodsmentioning

confidence: 99%