Biaxial orientation in HDPE films: comparison of infrared spectroscopy, X-ray pole figures and birefringence techniques

Ajji, Abdellah; Zhang, X.; Elkoun, Saïd

doi:10.1016/j.polymer.2005.03.002

Cited by 39 publications

(42 citation statements)

References 19 publications

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“…Such quantitative differences in spectroscopic (FTIR) and X-ray diffraction have also been reported in a recent study. [31] A reasonable estimate of the molecular orientation in LDPE can also be obtained from the ZZ-backscattered Raman spectrum. Pigeon et al [11] reported an increase in the intensity ratio I 1132 /I 1064 with the increase in orientation factors P 2 and P 4 .…”

Section: Resultsmentioning

confidence: 99%

Molecular orientation evolution during low‐density polyethylene blown film extrusion using real‐time Raman spectroscopy

Gururajan¹,

Ogale²

2008

J Raman Spectroscopy

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Real-time polarized Raman spectroscopy was used in this study to measure the molecular orientation evolution during blown film extrusion of low-density polyethylene (LDPE). Spectra were obtained at different locations along the blown film line, starting from the molten state near the die and extending up to the solidified state near the nip rolls. The trans C-C symmetrical stretching vibration of polyethylene (PE) at 1132 cm −1 was analyzed for films possessing uniaxial symmetry. For the given peak, the principal axis of the Raman tensor is coincident with the c-axis of the orthorhombic crystal, and was used to solve a set of intensity ratio equations to obtain second ( P 2 (cos θ) ) and fourth ( P 4 (cos θ ) ) moments of the orientation distribution function. The orientation parameters (P 2 , P 4 ) were found to increase along the axial distance in the film line even past the frost-line height (FLH). The P 2 values also showed an increasing trend with crystalline evolution during extrusion, consistent with past observations that molecular orientation takes place even after the blown film diameter is locked into place. It was also found that the integral ratio (I 1132 /I 1064 ) obtained from a single, ZZ-back-scattered mode can provide a reasonable estimate of molecular orientation. These results indicate the potential of real-time Raman spectroscopy as a rapid microstructure monitoring tool for better process control during blown film extrusion.

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Section: Resultsmentioning

confidence: 99%

Molecular orientation evolution during low‐density polyethylene blown film extrusion using real‐time Raman spectroscopy

Gururajan¹,

Ogale²

2008

J Raman Spectroscopy

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“…However, the accuracy and precise significance of the different orientation factors determined from these techniques is to be established, although some studies in the past addressed partially this issue as well as their correlations to structure and properties [7][8][9][10][11][12][13][14][15][16]. In a recent paper [19], we addressed this issue for high-density polyethylene (HDPE), for which some discrepancies were observed and discussed. However, because of the much higher crystalline content and typical structure that could be developed in an HDPE (row nucleated structure) in comparison with an LLDPE (random lamellar structure) [20], those results could not be transposed to LLDPE.…”

Section: Introductionmentioning

confidence: 99%

“…A comparison is also made with the approaches of Kissin and Krishnaswamy mentioned above. A first paper was dedicated to the case of HDPE [19] and this second paper addresses the case of LLDPE.…”

Section: Introductionmentioning

confidence: 99%

Biaxial orientation in LLDPE films: Comparison of infrared spectroscopy, X‐ray pole figures, and birefringence techniques

Ajji¹,

Zhang²,

Elkoun³

2006

Polymer Engineering & Sci

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In this study, linear low-density polyethylene films were produced using different processes (film blowing and biaxial orientation) and processing conditions. The orientation of the films was characterized in terms of their biaxial crystalline, amorphous, and global orientation factors using birefringence, tilted incidence polarized Fourier Transform Infrared Spectroscopy (FTIR), and Xray diffraction pole figures. Evaluation of a simplified FTIR procedure without the use of the tilted method for the determination of crystalline orientation factors proposed in the literature is also evaluated and assessed. The results indicate that FTIR overestimate the crystalline orientation factors, particularly for the crystalline a-axis. Significant discrepancies are also observed for the b-axis orientation, which may be due to an overlap of the amorphous phase contribution. Those differences are larger for films with low orientation, such as blown films. Amorphous phase orientation from FTIR depends on the band used and is not necessarily in agreement with that determined from the combination of X-ray and birefringence. The simplified FTIR procedure is proven to be inadequate in the case of linear low-density polyethylene blown films studied having a random lamellar crystalline morphology. POLYM. ENG. SCI., 46:1182-1189, 2006.

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“…In film blowing lines in industry, online measurements of the film quality are established by means of optical quality check in order to locate surface defects such as shark‐skin or to detect the occurrence of melt fracture. On a smaller scale, several researchers report on real‐time measurements combined with different methods such as SALS, Raman spectroscopy or birefringence . 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.…”

Section: Introductionmentioning

confidence: 99%

“…On a smaller scale, several researchers report on real-time measurements combined with different methods such as SALS, [24] Raman spectroscopy [25] or birefringence. [15,26] 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.…”

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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Biaxial orientation in HDPE films: comparison of infrared spectroscopy, X-ray pole figures and birefringence techniques

Cited by 39 publications

References 19 publications

Molecular orientation evolution during low‐density polyethylene blown film extrusion using real‐time Raman spectroscopy

Molecular orientation evolution during low‐density polyethylene blown film extrusion using real‐time Raman spectroscopy

Biaxial orientation in LLDPE films: Comparison of infrared spectroscopy, X‐ray pole figures, and birefringence techniques

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

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