Influence of the mixing time on the phase structure and glass‐transition behavior of poly(ethylene terephthalate)/poly(ethylene‐2,6‐naphthalate) blends

Wang, Tao; Wu, Wei; Chen, Yu; Ren, Wei; Luo, Qi

doi:10.1002/app.39196

Cited by 6 publications

(7 citation statements)

References 23 publications

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“…The observed behavior of the sequence length and the degree of randomness in this study are consistent with previous reports of the copolymerization of PET/PEN and PET/PBT …”

Section: Resultssupporting

confidence: 93%

“…This suppression in T mB becomes more exaggerated with reaction time. Experimental studies have previously shown that substantial T m depression is observed in the copolyesters of PET/PEN, PET/PBT, PBT/PBS, PBT/PBN, and PBN/poly(butylene adipate) . Lu and Windle observed the same trend in T mB independent of whether the samples had been quiescently or strain crystallized.…”

Section: Resultsmentioning

confidence: 75%

“…In this study, the degree of randomness and sequence length of the product PET/PEN random/block copolymers are determined by statistical calculation using the 1 H NMR peak area ratios . This quantitative approach has been applied in many studies by 1 H NMR . The mole fractions of PET ( F T ) and PEN ( F N ) units in the PET/PEN copolymers are calculated by the ratio of the three ethylene glycol residues obtained by three 1 H NMR peak areas ( A TET , A NET , and A NEN ) and the total peak area A (= A TET + A NET + A NEN ) as

F_{T} = \frac{0.5 A_{NET} + A_{TET}}{A}, F_{N} = \frac{0.5 A_{NET} + A_{NEN}}{A} .

…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of statistical PET/PEN random block copolymers and their crystallizability in the bulk and at the surface

Shinotsuka

Assender

Claridge

2018

J of Applied Polymer Sci

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A series of PET/PEN copolyesters were synthesized by molten transesterification. The degree of randomness and the sequence length of the copolymers were determined by 1H NMR spectroscopy, and the changes in the bulk glass transition temperature (TgB), bulk crystallization temperature (TcB), and bulk melting temperature (TmB) were observed by DSC. A clear relationship was obtained between the observed enthalpy of melting (ΔHm) and degree of randomness (B), and TmB was suppressed for the midcompositions. As with their homopolymer counterparts, there was significant depression in crystallization temperature at the surface (TcS) of the random/block copolymers compared with the bulk, and so surface‐localized crystallization could be induced in spin‐coated thick films (thickness ranging from ca. 400 to 700 nm) by annealing at a temperature in which the surface region is mobile, but the bulk is not. The formation of these clear surface crystals allows the morphology to be directly imaged by AFM, and we observed that the crystallizability and the lamellar morphology of the surface crystals deviated from those of the original homopolymers, depending on the mixing ratio of PET/PEN and degree of randomness. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46515.

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“…The observed behavior of the sequence length and the degree of randomness in this study are consistent with previous reports of the copolymerization of PET/PEN and PET/PBT …”

Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 75%

F_{T} = \frac{0.5 A_{NET} + A_{TET}}{A}, F_{N} = \frac{0.5 A_{NET} + A_{NEN}}{A} .

…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of statistical PET/PEN random block copolymers and their crystallizability in the bulk and at the surface

Shinotsuka

Assender

Claridge

2018

J of Applied Polymer Sci

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“…A desirable combination of PET and PEN can be achieved through blending. The phase structure, transesterification reaction, crystallization, and physical characteristics of TN blends have been studied, which revealed distinct miscibility levels for each blend. − When molten PET and PEN are blended, a transesterification reaction occurs, which results in the formation of block copolymers, with increasingly random distribution as the reaction proceeds. , Khonakdar et al studied the transesterification reaction and copolymer structure formation for various average sequence block lengths and degrees of randomness. A decrease in the block length results in an incease in elasticity and relaxation time .…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure and Tensile Fracture Morphology of Poly(ethylene terephthalate)-co-poly(ethylene 2,6-naphthalate) Block Copolyesters and Fibers

Chen

Yang

Lin

et al. 2020

Ind. Eng. Chem. Res.

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Poly(ethylene terephthalate) (PET) and poly(ethylene 2,6-naphthalate) (PEN) homopolyesters were synthesized and then copolymerized at different molar feed ratios into PET-co-PEN (TN) block copolyesters. The sequence distribution of the TN copolyesters was analyzed through proton nuclear magnetic response spectroscopy. The results demonstrated that the block segments of PET and PEN are highly miscible and tend to be randomly or nearly randomly distributed in the synthesized TN molecular chains. For TN block copolyesters with PET as the main component and number-averaged sequence length of PET > 3, wide-angle X-ray diffraction (WAXD) profiles indicated that all TN copolyester crystals were related to PET. TN block fibers were produced from a TN block copolyester through melt spinning at a 90:10 PET-to-PEN molar feed ratio and then subjected to different heat treatments. The relaxation of the oriented amorphous chain at elevated temperatures reduced the birefringence of the TN fiber. When the relaxation heat treatment time or stretching was longer, the oriented amorphous molecular chains were reoriented and crystallized, which increased the birefringence of the TN fiber. The differences in the segmental mobility of PET and PEN led to a multinecking and a mushroom-head morphology with transverse striations along the fiber axis because of the snapback effect after tensile failure.

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“…As the reaction progresses, the sequence length L T and L N gradually decreases and degree of randomness B increases, depending on the ester exchange reaction rate. The observed behavior of the sequence length and the degree of randomness are consistent with previous reports of the copolymerization of PET/PEN …”

Section: Resultsmentioning

confidence: 97%

Crystalline morphologies at the surface of PET/PEN random copolymer films

Shinotsuka

Assender

2019

Polymer Crystallization

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Crystalline Morphologies of the Surface of Random Copolymer Films In their work reported in article e10087, Shinotsuka and Assender demonstrate that polymers can crystallize preferentially at the free surface when annealed at temperatures between the surface and bulk glass transition temperatures, forming dendritic structures observable by AFM. This is a near‐surface rather than a thin‐film phenomenon. A 436nm thick 50/50 PET/PEN random copolymer shows surface crystallization at a temperature 90°C lower than bulk crystallization. In 31nm films, the crystallization is affected by the confinement of the thin film and the first stages of crystallization, near the nucleus, form with one morphology (orientation) and then switch to clearer dendrites, likely of edge‐on orientation. (DOI: https://doi.org/10.1002/pcr2.10087)

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Influence of the mixing time on the phase structure and glass‐transition behavior of poly(ethylene terephthalate)/poly(ethylene‐2,6‐naphthalate) blends

Cited by 6 publications

References 23 publications

Synthesis of statistical PET/PEN random block copolymers and their crystallizability in the bulk and at the surface

Synthesis of statistical PET/PEN random block copolymers and their crystallizability in the bulk and at the surface

Crystal Structure and Tensile Fracture Morphology of Poly(ethylene terephthalate)-co-poly(ethylene 2,6-naphthalate) Block Copolyesters and Fibers

Crystalline morphologies at the surface of PET/PEN random copolymer films

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