Crystallization from Anisotropic Polymer Melts

Silva, Daniel P. da; Holt, J.J.; Pratumshat, Supatra; Pascoal‐Faria, Paula; Mateus, Artur; Mitchell, Geoffrey R.

doi:10.1002/9783527839247.ch10

Cited by 2 publications

(2 citation statements)

References 40 publications

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“…The data shown in Figure 15 show a modest level of anisotropy for PP1 compared to the higher level of anisotropy exhibited by the data for PP2. In both cases, the maximum scattering is observed at α = 0 • and 180 • , indicating that the lamellar stack is arranged parallel to the flow direction, with the lamellar growth direction perpendicular to the flow direction, as is expected for a system nucleated by row nuclei [20,21,32].…”

Section: Preferred Crystal Orientationsupporting

confidence: 51%

“…scattering is observed at α = 0° and 180°, indicating that the lamellar stack is arranged parallel to the flow direction, with the lamellar growth direction perpendicular to the flow direction, as is expected for a system nucleated by row nuclei [20,21,32]. We applied the methodology of Mitchell and co-workers to evaluate the orientation parameters for the data in Figure 15, and the results are shown in Table 3.…”

Section: Preferred Crystal Orientationmentioning

confidence: 88%

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Time and Spatially Resolved Operando Small-Angle X-ray Scattering Measurements during Injection Moulding of Plastics

Arioli,

Massano,

da Silva

et al. 2023

JMMP

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We recently introduced the possibility of performing operando small-angle X-ray scattering measurements using a novel industrially relevant injection moulding system for plastics. We show that useful time-resolving measurements can be performed with a time-cycle of 1 s and highlight the possible steps to reduce this to 0.5 s. We show how we can use the transmission measurements to provide a time marker when plastic first enters the mould cavity in the region probed by the incident X-ray beam. We show the opportunities provided by this experimental stage mounted on the NCD-SWEET beamline at ALBA to probe the reproducibility of the injection moulding system on different scales. The design of the equipment allowed for the development of the structure and the morphology to be evaluated in different parts of mould cavity, and we evaluated any differences in a rectangular mould cavity. We identified future prospects for this equipment in terms of novel mould heating and cooling systems and the opportunities for quantitatively evaluating radical approaches to injection moulding technology.

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Section: Preferred Crystal Orientationsupporting

confidence: 51%

Section: Preferred Crystal Orientationmentioning

confidence: 88%

Time and Spatially Resolved Operando Small-Angle X-ray Scattering Measurements during Injection Moulding of Plastics

Arioli,

Massano,

da Silva

et al. 2023

JMMP

View full text Add to dashboard Cite

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Property mapping of LDPE during 3D printing: evaluating morphological development with X-ray scattering

et al. 2023

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Direct digital manufacturing has been identified as one of the key tools of Industry 4.0 and it enables the creation of products directly through digital definition. Commonly known as additive manufacturing, it comprises a set of technologies that are expressively agile in small-scale productions and prototyping, in comparison to conventional mass manufacturing processes, such as injection molding of plastics. It streamlines mass customization, allows the production of highly complex objects, and has been broadly applied in several fields, from medical devices to the aerospace industry. Although a new era of design possibilities and accessibility was unveiled, most developments are focused on shape reproduction precision and the development of new feeding systems and materials. This work is focused on a shift in design for additive manufacturing, where the polymer properties, by means of the adjustment of the process conditions (extrusion rate, the write speed, and the nozzle temperature, among others), constitute a decision-making variable. In order to evaluate the morphology of semicrystalline polymers during extrusion-based 3D printing, in-situ time-resolving small and wide-angle X-ray scattering measurements were performed at the ALBA synchrotron light source in Barcelona (Spain). The goal of this research is to develop a material property mapping methodology during semicrystalline polymer melt extrusion-based 3D printing Some experiments were performed with low-density polyethylene, and we were able to confirm a correlation between the extrusion rate and writing speed of the printing with the level of preferred orientation of the chain folded lamellar crystals in the extrudate.

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Crystallization from Anisotropic Polymer Melts

Cited by 2 publications

References 40 publications

Time and Spatially Resolved Operando Small-Angle X-ray Scattering Measurements during Injection Moulding of Plastics

Time and Spatially Resolved Operando Small-Angle X-ray Scattering Measurements during Injection Moulding of Plastics

Property mapping of LDPE during 3D printing: evaluating morphological development with X-ray scattering

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