An application of temperature modulated differential scanning calorimetry to the exothermic process of poly(ethylene terephthalate) crystallization

Toda, Akihiko; Tomita, Chiyoko; Hikosaka, Masamichi; Saruyama, Yasuo

doi:10.1016/s0032-3861(97)85623-6

Cited by 42 publications

(15 citation statements)

References 7 publications

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“…In analogy to the heating run, when cooling with a constant rate, the temperature dependence of the rate of crystallization shows up in the signal. This was shown in works of Toda et al…”

Section: Introductionsupporting

confidence: 69%

“…In analogy to the heating run, when cooling with a constant rate, the temperature dependence of the rate of crystallization shows up in the signal. This was shown in works of Toda et al 6 Carrying out quasi-isothermal temperature-modulated DSC measurements in an investigation of several semicrystalline polymer systems, we have compared the amplitudes of the dynamic heat capacity in the melting ranges. 7 Particularly high signals were found for polyethylene (PE) and poly(ethylene oxide) (PEO).…”

Section: T*(t) ) T H + δTmentioning

confidence: 79%

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Dynamics of Surface Crystallization and Melting in Polyethylene and Poly(ethylene oxide) Studied by Temperature-Modulated DSC and Heat Wave Spectroscopy

et al. 2001

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Polymers with a high longitudinal diffuse mobility within the crystallites are known to show a continuous, reversible surface melting and crystallization; temperature changes are accompanied by shifts of the crystalline-amorphous interface, resulting in a crystal thickening on cooling and a thickening of the amorphous layers on heating. In measurements of the dynamic heat capacity c*(ω), the process shows up as a strong excess contribution which increases up to the temperature of the final irreversible crystal melting. Experiments were carried out for linear polyethylene (LPE) and poly(ethylene oxide) (PEO). Employing both a temperature-modulated differential scanning calorimeter (TMDSC) and a heat wave spectrometer (HWS), thereby covering the frequency range from 10 -3 to 10 2 Hz, we could analyze the process dynamics. The times required for the surface melting or crystallization were deduced from the change at the signal amplitude with frequency. They are remarkably long. For temperatures near to the respective final melting points we found about 12 s for the LPE sample and 120 s for PEO. The dynamic heat capacity of PE measured by TMDSC at low frequencies corresponds to the temperature dependence of the crystallinity. A comparison with the results of a SAXS structure analysis showed perfect agreement. For PEO the quasi-stationary conditions were not reached. Even at the lowest frequencies probed by TMDSC, the dynamic heat capacity was still below the value expected on a basis of the temperature dependence of the crystallinity determined by SAXS. In determinations of the dynamic heat capacity by TMDSC and HWS, it is in general necessary to correct the raw data to account for the inner heat flow resistance, additional heat capacities, and delay times introduced by the electronics. The corrections can be accomplished by an appropriate modeling of the measuring devices.

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“…In analogy to the heating run, when cooling with a constant rate, the temperature dependence of the rate of crystallization shows up in the signal. This was shown in works of Toda et al…”

Section: Introductionsupporting

confidence: 69%

Section: T*(t) ) T H + δTmentioning

confidence: 79%

Dynamics of Surface Crystallization and Melting in Polyethylene and Poly(ethylene oxide) Studied by Temperature-Modulated DSC and Heat Wave Spectroscopy

et al. 2001

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“…A temperature variation of the effective activation energy can be derived from the data by Toda et al, [20,21] (5) and that the a value does not change significantly over the modulation period, one can easily arrive at Equation (14):…”

Section: Resultsmentioning

confidence: 99%

“…We used Equation (14) to convert the dðln GÞ dT values [20] into the values of the effective activation energy. In agreement with our data (Figure 2), the estimated activation energies (Figure 4) are negative and increase with decreasing the crystallization temperature.…”

Section: Resultsmentioning

confidence: 99%

Untitled

Vyazovkin¹,

Sbirrazzuoli

2002

Macromol. Rapid Commun.

109

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“…The method has been mainly employed in glass transition to examine the relaxation phenomena as temperature and frequency dispersions [ 2 ]. Because temperature modulation also influences the degree of supercooling or superheating of the kinetics of first-order phase transitions, we can obtain valuable information regarding the transition kinetics [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ] such as crystallization [ 3 , 9 ], melting [ 4 , 6 , 9 ], and solid-solid phase transitions [ 7 , 10 ] of polymers [ 3 , 4 , 6 , 7 , 8 ], water [ 9 ], and metal alloy [ 10 ]; the heating only condition of Figure 1 is utilized to examine the one-way irreversible transition on heating. The typical responses are schematically shown in Figure 2 for the case of crystalline polymer, which is prepared by quenching and in the state of glass before the heating run.…”

Section: Introductionmentioning

confidence: 99%

Temperature-Modulated Scanning Calorimetry of Melting–Recrystallization of Poly(butylene terephthalate)

Toda

2021

Polymers

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The melting and recrystallization behaviors of poly(butylene terephthalate) (PBT) were investigated using temperature-modulated scanning calorimetry in both fast- and conventional slow-scan modes. With this method, the response of multiple transition kinetics, such as melting and recrystallization, can be differentiated by utilizing the difference in the time constants of the kinetics. In addition to the previous result of temperature-modulated fast-scan calorimetry of polyethylene terephthalate (PET), the supporting evidence of another aromatic polyester, PBT, confirmed the behavior of the exothermic process of recrystallization, which proceeds simultaneously with melting on heating scan in the temperature range of double melting peaks starting just above the crystallization temperature up to the main melting peak. Because the crystallization of PBT is much more pronounced than that of PET, similar behavior of recrystallization was obtained by the conventional temperature-modulated differential scanning calorimetry at a slow-scan rate.

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An application of temperature modulated differential scanning calorimetry to the exothermic process of poly(ethylene terephthalate) crystallization

Cited by 42 publications

References 7 publications

Dynamics of Surface Crystallization and Melting in Polyethylene and Poly(ethylene oxide) Studied by Temperature-Modulated DSC and Heat Wave Spectroscopy

Dynamics of Surface Crystallization and Melting in Polyethylene and Poly(ethylene oxide) Studied by Temperature-Modulated DSC and Heat Wave Spectroscopy

Untitled

Temperature-Modulated Scanning Calorimetry of Melting–Recrystallization of Poly(butylene terephthalate)

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