Segregation behavior of polyethylene with broad molecular weight distribution by annealing procedure in temperature gradient

Siriprumpoonthum, Monchai; Mieda, Naoya; Nobukawa, Shogo; Yamaguchi, Masayuki

doi:10.1007/s10965-011-9661-z

Cited by 9 publications

(8 citation statements)

References 16 publications

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“…Temperature gradient might be one of the triggers. Segregation behavior of molecular weight due to the temperature gradient under the melt has been confirmed for PE . Low molecular weight fraction tends to localize on the surface at the high temperature side and vice versa.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Crystallization/Melting Kinetics and Morphological Analysis of Polyphenylene Sulfide

Furushima

Nakada

Yoshida

et al. 2017

Macro Chemistry & Physics

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Crystallization and melting kinetics of polyphenylene sulfide (PPS) are determined using fast scanning calorimetry. The temperature dependence of half‐time crystallization of isothermally melt‐crystallized PPS shows a downward convex curve with a minimum at 160 °C. The minimum crystallization half‐time is about 3 s. The analysis of heating rate dependence of the melting temperature reveals a zero‐entropy‐production melting temperature of the sample. The microstructure of the sample, which is prepared by fast scanning calorimetry, is investigated by small‐angle X‐ray scattering and polarizing optical microscopy. The crystallinity and lamellar thickness of the sample annealed for 400 s decrease with decreasing crystallization temperature. The size of spherulites becomes small as the isothermal temperature is decreased. Transcrystalline morphology is observed near the surface between the sample and nitrogen gas at a crystallization temperature of 120 °C. The thickness of the transcrystalline layer disappears as the isothermal temperature is increased.

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Section: Resultsmentioning

confidence: 99%

“…Segregation behavior of molecular weight due to the temperature gradient under the melt has been confirmed for PE. [47] Low molecular weight fraction tends to localize on the surface at the high temperature side and vice versa. A large temperature gap leads to pronounced segregation.…”

Section: Morphologymentioning

confidence: 99%

Crystallization/Melting Kinetics and Morphological Analysis of Polyphenylene Sulfide

Furushima

Nakada

Yoshida

et al. 2017

Macro Chemistry & Physics

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“…7 However, the intensities of neither peak change significantly. This result indicates Apparently, the molecular weight of the surface sample at 250°C is low, which is consistent with the ATR-FTIR results.…”

Section: Segregation Behaviormentioning

confidence: 95%

Surface localization of poly(methyl methacrylate) in a miscible blend with polycarbonate

Sako

Nobukawa

Yamaguchi

2015

Polym J

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A new method to localize poly(methyl methacrylate) (PMMA) at the surface of a miscible blend with polycarbonate (PC) is demonstrated. Low-molecular-weight PMMA, which is found to be miscible with PC, is used in this study. After annealing the PC/PMMA blend in a temperature gradient, PMMA is found to localize on the high temperature side, as detected by infrared spectroscopy and molecular weight measurements. Furthermore, the sample exhibits good transparency even after annealing. This phenomenon is notable because it is applicable to enhancing the anti-scratch properties of PC.

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“…have shown that for high‐density PE, annealing causes a significant decrease in the thickness of the interfacial layer and the amorphous phase and an increase in the lamellar thickness. It is well known that phase changes of PE during annealing result from rearrangement . Two possible types of rearrangement mechanisms have been revealed by Matsuda .…”

Section: Introductionmentioning

confidence: 99%

In situ confocal micro‐Raman spectroscopic investigation of rearrangement kinetics and phase evolution of UHMWPE during annealing

2014

J Raman Spectroscopy

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Ultrahigh molecular weight polyethylene was investigated using in situ confocal micro-Raman spectroscopy during annealing at 110.0°C. Based on the Raman spectra, crystalline, amorphous, and all-trans noncrystalline fractions were recognized to evaluate rearrangement kinetics during isothermal annealing at 110.0°C and phase evolution during cooling from 110.0 to 30.0°C. For the crystalline fraction, a substantial increase from 0.600 ± 0.001 to 0.639 ± 0.008 was observed during the first 24.2 min of annealing; a very gradual increase from 0.639 ± 0.001 to 0.679 ± 0.001 occurred during the following 114.6 min. For the amorphous phase fraction, conversely, a sharp decrease from 0.240 ± 0.000 to 0.213 ± 0.004 was exhibited during the first 24.2 min of annealing, and then, a flat decrease happened from 0.213 ± 0.004 to 0.192 ± 0.001 as time expanded to 138.8 min. For the all-tans noncrystalline fraction, a gradual decrease was shown from 0.160 ± 0.000 at 0.0 min to 0.128 ± 0.001 at 138.8 min. The rearrangement rate constant K was obtained to be 0.632 by an Avrami equation. During cooling from 110.0 to 30.0°C, there were two phase evolution regions: region 1 from 110.0 to 90.0°C and region 2 from 90.0 to 30.0°C. The crystal lamella thickened faster in region 1 than in region 2. The amorphous layer continually decreased in content in the combined region of 1 and 2. The all-trans noncrystalline phase obviously decreased in region 1 and then almost maintained a constant level in region 2.

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Segregation behavior of polyethylene with broad molecular weight distribution by annealing procedure in temperature gradient

Cited by 9 publications

References 16 publications

Crystallization/Melting Kinetics and Morphological Analysis of Polyphenylene Sulfide

Crystallization/Melting Kinetics and Morphological Analysis of Polyphenylene Sulfide

Surface localization of poly(methyl methacrylate) in a miscible blend with polycarbonate

In situ confocal micro‐Raman spectroscopic investigation of rearrangement kinetics and phase evolution of UHMWPE during annealing

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