Real‐time wide‐angle X‐ray diffraction during polyethylene blown film extrusion

Gururajan, Giriprasath; Shan, Hangguan; Lickfield, Gary C.; Ogale, Amod A.

doi:10.1002/pen.21111

Cited by 19 publications

(21 citation statements)

References 22 publications

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“…Recently, efforts to monitor the structure evolution during film blowing in real time have been made, using techniques such as small-angle light scattering (Bullwinkel et al, 2001), Raman spectroscopy (Gururajan & Ogale, 2009) or X-ray diffraction using sealed tubes (Gururajan et al, 2008). While the advantages of using commercial X-ray sources for structural analysis are evident, they still lack the collimation which is so beneficial when using synchrotron radiation.…”

Section: Film Blowingmentioning

confidence: 99%

Polymer crystallization studies under processing-relevant conditions at the SAXS/WAXS DUBBLE beamline at the ESRF

et al. 2013

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Recent developments on the experimental infrastructure and the acquisition of new detectors on the Dutch-Belgian beamline BM26B at the ESRF offer novel and promising possibilities for synchrotron X-ray experiments in the field of polymer crystallization under processing-relevant conditions. In this contribution, some of the most recent experiments mimicking conditions similar to those relevant for the plastics processing industry are discussed. Simultaneous thermal analysis and wide-angle X-ray scattering (WAXS) experiments, at the millisecond time-frame level, on -nucleated isotactic polypropylene (i-PP) samples subjected to ballistic cooling up to 230 K s À1 , show that the efficiency of the nucleating agent can be suppressed when quenched cooling rates higher than 130 K s À1 are used. In situ WAXS experiments using small-scale industrial equipment during a real film blowing process reveal the dependence of the onset of crystallinity (the so-called freeze line) and the crystal orientation as a function of different take-up and blow-up ratios. In situ small-angle X-ray scattering (SAXS) experiments during high-flow fields reveal the formation of shish and kebab structures in i-PP as a function of the imposed stress. Quantitative analysis of i-PP flow-induced structures is presented. The beamline specifications required to obtain high quality and industrially relevant results are also briefly reported.

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Section: Film Blowingmentioning

confidence: 99%

Polymer crystallization studies under processing-relevant conditions at the SAXS/WAXS DUBBLE beamline at the ESRF

et al. 2013

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“…However, all of these methods, while useful in some cases, are indirect and cannot result in differences in the blown film process for polymers of different structures. Therefore, with the continuous development of detection methods, some researchers have tried to in situ study the film blowing process by using synchrotron radiation technology in recent years . Giri Gururajan and coworkers used WAXD technology to establish a real‐time detection measurement, which is possible to detect the structure of bubble during blown film process, and roughly plot the LDPE bubble crystallization and orientation curve.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, with the continuous development of detection methods, some researchers have tried to in situ study the film blowing process by using synchrotron radiation technology in recent years . Giri Gururajan and coworkers used WAXD technology to establish a real‐time detection measurement, which is possible to detect the structure of bubble during blown film process, and roughly plot the LDPE bubble crystallization and orientation curve. Van Drongelen and Troisi used WAXD measurement and the first time used SAXS technology in situ to detect the structural evolution of several different molecular structure of PE at different processing conditions.…”

Section: Introductionmentioning

confidence: 99%

A real‐time WAXS and SAXS study of the structural evolution of LLDPE bubble

Zhao

Zhang

Ali

et al. 2018

J Polym Sci B Polym Phys

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The structural evolution during the linear low-density polyethylene (LLDPE) film blowing has been studied with a combination of home-made blown film apparatus and in situ WAXS and SAXS measurements. Analyzing the evolution of orientation parameters and crystallinity of the bubble shows that the blown film process can be divided into four regions. Distinctly different features of LLDPE bubble are observed in first three regions: (a) lower orientation parameters during the blown film process, (b) higher crystallinity is required to form a deformable crystalline crosslinked network, and (c) the weaker stretching effect and the difficulty of reaching equilibrium when the crystal network deforms. These results should provide a basis for understanding the poor blown film stability of LLDPE.

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“…Among various characterization methods, X‐ray diffraction techniques such as Small Angle X‐ray Scattering (SAXS) or Wide Angle X‐ray Diffraction (WAXD), provides for a direct measurement technique to obtain the crystallinity and molecular orientation within a sample. For practical reasons, on‐line structure analysis using X‐ray based methods, was still reserved for lab‐scale environments . Combining a pilot‐plant film blowing setup with X‐ray leads to many impracticalities and limits the accessibility of the blown film line because of the presence of radiation sources.…”

Section: Introductionmentioning

confidence: 99%

Structure Development of Low-Density Polyethylenes During Film Blowing: A Real-Time Wide-Angle X-ray Diffraction Study

Drongelen

Cavallo

Balzano

et al. 2014

Macromol. Mater. Eng.

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We studied experimentally the structure development during film blowing for three different low-density polyethylenes at four different processing conditions. For this, we combined blown film extrusion with in situ X-ray diffraction at a synchrotron radiation beam line. The measurements were performed at rheological similar conditions at the die exit, with each grade possessing different molecular properties in terms of molecular weight distribution and branching content. The development of crystallinity and molecular orientation was determined as function of the distance from the die. It is shown that this approach provides a valuable method to study structure evolution during film blowing and can be used to validate results from numerical models and help to improve and/or extend these models.

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Real‐time wide‐angle X‐ray diffraction during polyethylene blown film extrusion

Cited by 19 publications

References 22 publications

Polymer crystallization studies under processing-relevant conditions at the SAXS/WAXS DUBBLE beamline at the ESRF

Polymer crystallization studies under processing-relevant conditions at the SAXS/WAXS DUBBLE beamline at the ESRF

A real‐time WAXS and SAXS study of the structural evolution of LLDPE bubble

Structure Development of Low-Density Polyethylenes During Film Blowing: A Real-Time Wide-Angle X-ray Diffraction Study

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