The triple melting behavior of poly(ethylene terephthalate): Molecular weight effects

Medellín‐Rodríguez, F. J.; Phillips, P. J.; Lin, Jianzhen; Campos, Ricardo Barrios

doi:10.1002/(sici)1099-0488(199708)35:11<1757::aid-polb9>3.3.co;2-6

Cited by 33 publications

(71 citation statements)

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“…The n values of the PET homopolymers ranged from 2.2–2.3 at various T c 's. Similar results have been reported in the literature for PET 5–8. In general, a value of n close to 3 represents an athermal nucleation process, followed by three‐dimensional crystal growth.…”

Section: Resultssupporting

confidence: 84%

“…However, PET still has some undesirable properties, especially slow crystallization behaviors, that limit its applications. Many investigations3–9 of its crystallization and melting behavior have sought to overcome the crystalline characteristics of PET, including those of copolymerization. Poly(trimethylene terephthalate) (PTT) is also a high‐performance polymer with numerous engineering applications 10–13.…”

Section: Introductionmentioning

confidence: 99%

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Crystallization behavior and morphology of poly(ethylene‐co‐trimethylene terephthalate)s

Lin

2004

J Polym Sci B Polym Phys

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The melt crystallization behaviors and crystalline structures of poly(ethylene terephthalate) (PET), poly(trimethylene terephthalate), and poly(ethylene‐co‐trimethylene terephthalate) (PETT) were investigated with differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X‐ray diffraction at various crystallization temperatures (Tcs). The PETT copolymers were synthesized via the polycondensation of terephthalate with ethylene glycol and trimethylene glycol (TG) in various compositions. The copolymers with 69.0 mol % or more TG or 31.0 mol % or less TG were crystallizable, but the other copolymers containing 34–56 mol % TG were amorphous. The DSC isothermal results revealed that the addition of a small amount of flexible TG (up to 21 mol %) to the PET structure slightly reduced the formation of three‐dimensional spherulites. A greater TG concentration (91–100%) in the copolyesters changed the crystal growth from two‐dimensional to three‐dimensional. The DSC heating scans after the completion of isothermal crystallization at various Tcs showed three melting endotherms for PET, PETT‐88, PETT‐84, and PETT‐79 and four melting endotherms for PETT‐9 and PETT. The presence of an additional melting endotherm could be attributed to the melting of thinner and imperfect copolyester crystallites. Analyses of the Lauritzen–Hoffman equation demonstrated that PETT‐88 had the highest values of the product of the lateral and folding surface free energies, and this suggested that the addition of small amounts of flexible trimethylene terephthalate segments to PET disturbed chain regularity, thus increasing molecular chain mobility. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4255–4271, 2004

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Section: Resultssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Crystallization behavior and morphology of poly(ethylene‐co‐trimethylene terephthalate)s

Lin

2004

J Polym Sci B Polym Phys

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“…The intensity of endotherm (III) decreases with increasing T c for all these polyesters. Some researchers3, 4, 14, 16, 27 investigated the effect of heating rate on endotherm (III), showing that its size decreased with increasing heating rate. Most of the researchers attributed endotherm (III) to the melting of crystallites formed by melting and recrystallization during the DSC heating scan.…”

Section: Resultsmentioning

confidence: 99%

“…We did not anneal PET at T c above 200 °C. In the literature3 it was reported that endotherms (II) and (III) merged into one when PET was annealed at a T c above 210 °C.…”

Section: Resultsmentioning

confidence: 99%

“…Poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) are high performance polymers which have been the subject of many investigations concerning their crystallization and melting behaviour. They can be crystallized from the melt over a wide range of supercooling conditions, and usually display three melting peaks during normal scanning in a differential scanning calorimeter 1–13. The lowest melting peak, which was observed about 10 °C above T c (crystallization temperature), was attributed to the fusion of crystals grown during secondary crystallization.…”

Section: Introductionmentioning

confidence: 99%

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Crystallization kinetics of poly(1,4-butylene-co-ethylene terephthalate)

Chou

Chang

et al. 2001

Polym. Int.

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Thermal properties relevant to the processing of PET fibers

Clerck

Rahier

Mele

et al. 2003

J of Applied Polymer Sci

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ABSTRACT:The thermal properties of poly(ethylene terephthalate) (PET) conventional fibers and microfibers are measured and compared to bulk samples. It is shown that the glass transition temperature (T g ) of the fibers can be monitored with modulated differential scanning calorimetry (MDSC). The T g region is about 30°C wide and shifted to approximately 110°C for conventional as well as for micro-PET fibers. The T g of these fibers is compared to the T g of cold-crystallized bulk samples. Upon crystallization, a shift and even a split up of T g is observed. The second T g is much broader and is situated around 90°C. This T g is related to the appearance of a rigid amorphous phase. In comparison, the mobility of the amorphous phase in fibers is even more restricted. The whole multiple melting profile observed on the fibers is the result of a continuous melting and recrystallization process, in contrast to bulk PET. The heat-set temperature is shown to trigger the start of melting and recrystallization. It is seen in the MDSC as an exotherm in the nonreversing signal and an excess contribution in the heat-capacity signal.

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The triple melting behavior of poly(ethylene terephthalate): Molecular weight effects

Cited by 33 publications

References 0 publications

Crystallization behavior and morphology of poly(ethylene‐co‐trimethylene terephthalate)s

Crystallization behavior and morphology of poly(ethylene‐co‐trimethylene terephthalate)s

Crystallization kinetics of poly(1,4-butylene-co-ethylene terephthalate)

Thermal properties relevant to the processing of PET fibers

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