Temporal evolution of structure in uniaxially stretched PET/PEI blends during constrained annealing: A real time birefringence study

Choi, Jun H.; Serhatkulu, T.; Çakmak, Mükerrem

doi:10.1016/j.polymer.2016.05.058

Cited by 6 publications

(4 citation statements)

References 23 publications

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“…(A) T cc , T g , T m of the blend's spheres: (literature value: Choi et al 5,6 ), stars: Calculated values from DSC (B) ΔT g of the blends…”

Section: Resultsmentioning

confidence: 99%

“…of the blend's spheres: (literature value: Choi et al 5,6 ), stars: Calculated values from DSC (B) ΔT g of the blends F I G U R E 3 Thermal analysis of poly (ethylene terephthalate) (PET)/poly (ether imide) (PEI) films, stretched at T g + 20 C at the stretch rate of 20 mm/min and 200 mm/min (for all compositions) (stretch ratio: 4 λ)) Figure 3. Thermal analysis of PET/PEI films, stretched at Tg + 20 at the stretch rate of 20 mm/min and 200 mm/min (for all compositions) (stretch ratio: 4Â)…”

Section: F I G U R E 2 (A) T Cc T G T Mmentioning

confidence: 99%

“…Choi et al reported the structure evolution of uniaxially stretched PET/PEI films during annealing and concluded that when the PEI concentration was low, at lower deformations heat setting leads to complete elimination of birefringence whereas at higher deformation levels, annealing leads to initial birefringence relaxation followed by rapid increase associated with oriented crystallization. 5,6 Mechanical and other physical properties of PET/PEI blends are notably influenced by the blend composition and processing conditions particularly by the chain orientation. There have been various offline studies on the effect of deformation during structure development, 4,9 however; understanding the performance requires an in-situ method to evaluate chain orientation during film formation or in post formation processing.…”

Section: Introductionmentioning

confidence: 99%

“…The flexible ether linkages enable melt processing of this polymer. PET/PEI blends are melt miscible 4,5,6,7,8 and by increasing PEI content, the T g increases while suppressing the tendency to crystallize and facilitate higher deformation levels to be achieved when stretched in rubbery state from amorphous precursors. Choi et al reported the structure evolution of uniaxially stretched PET/PEI films during annealing and concluded that when the PEI concentration was low, at lower deformations heat setting leads to complete elimination of birefringence whereas at higher deformation levels, annealing leads to initial birefringence relaxation followed by rapid increase associated with oriented crystallization 5,6 …”

Section: Introductionmentioning

confidence: 99%

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Mechano‐opticalbehavior in poly (ethylene terephthalate)/poly (ether imide) blends

Mutlu

Jain

Yook

et al. 2021

Journal of Polymer Science

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Mechano-optical behavior and related structural evolution during uniaxial stretching of melt miscible poly (ethylene terephthalate) (PET)/poly (ether imide) (PEI) blends were studied near their glass transition temperature using an instrumented machine that measures true stress, true strain and spectral birefringence simultaneously. Stretching from amorphous state, two distinct stress-optical regimes were observed at temperatures between T g and T cc (cold crystallization).Near T g , a typical photoelastic behavior persists until a critical temperature above which temperature independent initial stress optical behavior is observed. At those temperatures above T g , where glassy behavior is observed, decreasing stretching rate was also found to eliminate this glassy photo elastic regime leading to the observation of a linear initial stress optical behavior that becomes temperature independent as expected from linear stress optical rule. Increasing PEI concentration in the blends suppresses crystallizability and increases temperature at which initial elastic region disappears giving way to pure liquid behavior where linear stress optical behavior is observed. This is attributed to the increase and broadening of the glass transition temperature with the addition of noncrystallizable PEI. In PET/PEI blends, the stress-optical coefficient (SOC), determined in a linear stress optical regime, was found to increase linearly with the increase in PEI concentration.

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“…(A) T cc , T g , T m of the blend's spheres: (literature value: Choi et al 5,6 ), stars: Calculated values from DSC (B) ΔT g of the blends…”

Section: Resultsmentioning

confidence: 99%

Section: F I G U R E 2 (A) T Cc T G T Mmentioning

confidence: 99%