Mechano optical behavior of polyethylene terephthalate films during simultaneous biaxial stretching: Real time measurements with an instrumented system

Hassan, Mohamed K.; Cakmak, Mukerrem

doi:10.1016/j.polymer.2013.09.045

Cited by 31 publications

(23 citation statements)

References 33 publications

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“…Figure shows the variations of Δ H cc and Δ H melt(SIC) and the corresponding percentage of crystallinity obtained for films stretched at different ASR's. PET oriented at 95 °C has developed SIC percentage values which agree well with those found from previous DSC studies conducted on biaxially oriented PET . For PEF, SIC is absent in the samples stretched at 95 °C but increases when PEF is oriented at 100 °C with increasing ASR.…”

Section: Resultssupporting

confidence: 86%

“…PET oriented at 95 °C has developed SIC percentage values which agree well with those found from previous DSC studies conducted on biaxially oriented PET. [34,35] For PEF, SIC is absent in the samples stretched at 95 °C but increases when PEF is oriented at 100 °C with increasing ASR. Accordingly, the cold crystallization phenomenon slightly decreases with ASR.…”

Section: Crystallinity and Shrinkagementioning

confidence: 99%

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Biaxial Orientation of Poly(ethylene 2,5‐furandicarboxylate): An Explorative Study

Berkel

Guigo

Kolstad

et al. 2018

Macro Materials & Eng

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The biaxial orientation behavior of poly(ethylene 2,5‐furandicarboxylate) (PEF) is studied in comparison to poly(ethylene terephthalate) (PET). PEF is a polyester that can be produced through similar steps as PET but using 100% biobased 2,5‐furandicarboxylic acid instead of terephthalic acid. This work highlights the stress–strain behavior of PEF during biaxial orientation at various temperatures. Strain hardening and strain‐induced crystallization in the oriented PEF samples generally appeared at higher stretch ratios for PEF than for PET at comparable molecular weight, while somewhat lower degrees of crystallinity are reached in PEF. Shrinkage in oriented PEF is found to be on par with PET in the region of the glass transition. Higher modulus and improved barrier properties, compared to PET, are found in the oriented materials when sufficiently high stretch ratios are applied in biaxial orientation.

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Section: Resultssupporting

confidence: 86%

Section: Crystallinity and Shrinkagementioning

confidence: 99%

Biaxial Orientation of Poly(ethylene 2,5‐furandicarboxylate): An Explorative Study

Berkel

Guigo

Kolstad

et al. 2018

Macro Materials & Eng

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“…Typical properties of COC includes; low density, high transparency, low water absorption, high rigidity, etc. Density is 1.02 g/cm 3 . The glass transition temperature (T g ) of used COC is 78 • C. We applied the single screw extrusion process to produce cast film measuring 250 µm in thickness.…”

Section: Methodsmentioning

confidence: 99%

“…Ryu et al [1] have shown that SOR does not hold at low temperatures close to T g or at high strain rates due to the contributions of glassy stress and photo-elastic constant, typically at room temperature. Hassan et al [2][3][4] discuss on-line measurements of birefringence and the development of higher order structures in investigations of mechano-optical behavior of PET films during stretching, reporting that SOR continues to apply up to the onset of strain hardening. Studies evaluating the control of strain-induced crystallinity in PET films with different deformation modes, including linear (generally assumed as the standard), exponential, logarithmic, and sigmoidal profile [5], indicate differences in crystallinity behavior.…”

Section: Introductionmentioning

confidence: 99%

Structural Formation of Cyclic Olefin Copolymer (COC) Films as Revealed by Real Time Retardation Measurements during Fast Stretching Process

Hashimoto

Ito

2018

Technologies

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This work reports on an experimental study of the fast stretching of a cyclic olefin copolymer (COC) film. We measured the stress retardation of the polymer film during fast stretching and identified a relationship between stress and birefringence. This relationship indicates that the film obeys the stress optical rule (SOR) at the onset of stretching. At slower stretching speeds, the stress optical constant (SOC) settles at a certain value. With faster stretching speeds, SOC values approach the photo-elastic constant (PEC). Our study also investigated the effects of stretching temperatures and stretching modes for both uniaxial stretching and biaxial stretching. We applied techniques of thermal analysis to evaluate higher order structures after fast stretching.

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“…The films used for the heat setting process were stretched at the rate of 0.125/s in the simultaneous biaxial , sequential biaxial and uniaxial constant width (UCW) modes at 95°C after a preheating period of about 7 min. In this text, the stretching ratios will be denoted as “A×B,” where “A” is the stretch ratio in the machine direction and “B” is the stretch ratio in the transverse direction.…”

Section: Methodsmentioning

confidence: 99%

Rapid structural changes that take place during constrained annealing of biaxially stretched pet films

Hassan

Çakmak

2016

Polym Eng Sci

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The aim of this work is to study the structural changes that take place during the heat setting of simultaneously and sequentially biaxially stretched polyethylene terephthalate films. The rate of structural rearrangement, as detected by real‐time birefringence and off‐line Raman spectroscopy, DSC thermal analysis and X‐rays, was found to be dependent on the state of the orientation and crystallinity attained by the samples during the stretching step. This suggested that the annealing behavior can be categorized into three regimes according to the birefringence behavior of the samples. At low deformations, the films not crystallized by strain exhibit complete birefringence relaxation without showing any sign of crystallization. The intermediate ratio samples that were stretched to the onset of the strain‐induced crystallization exhibited the highest levels of birefringence increase after a short relaxation. The samples stretched well above the onset of the strain‐induced crystallization exhibited intermediate level of birefringence and crystallinity increase. Therefore, the classification of the three regimes was found to be related to the onset of the strain‐induced crystallization during the stretching step. POLYM. ENG. SCI., 57:550–562, 2017. © 2016 Society of Plastics Engineers

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Mechano optical behavior of polyethylene terephthalate films during simultaneous biaxial stretching: Real time measurements with an instrumented system

Cited by 31 publications

References 33 publications

Biaxial Orientation of Poly(ethylene 2,5‐furandicarboxylate): An Explorative Study

Biaxial Orientation of Poly(ethylene 2,5‐furandicarboxylate): An Explorative Study

Structural Formation of Cyclic Olefin Copolymer (COC) Films as Revealed by Real Time Retardation Measurements during Fast Stretching Process

Rapid structural changes that take place during constrained annealing of biaxially stretched pet films

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