Effects of Blending on the Melting and Crystallization of Polyethylene ahd Polypropylene under High Pressure

Nakafuku, Chitoshi

doi:10.1295/polymj.15.641

Cited by 7 publications

(3 citation statements)

References 14 publications

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“…T m of ECC is about 141 8C which is considered to be almost the same temperature as the value of the equilibrium melting temperature of PE. Pressure dependence of T 0 m (ECC) in PE[9] is 0.30 KMPa 21 and that of T m (FCC)[10] is 0.28 KMPa 21 . The temperature difference of T 0 m and T m is about 9 8C in PE.…”

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Melting parameters of poly(glycolic acid)

Nakafuku

Yoshimura

2004

Polymer

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confidence: 92%

Melting parameters of poly(glycolic acid)

Nakafuku

Yoshimura

2004

Polymer

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“…Higher pressure is also associated with higher chain end mobility, especially in extension. The melting temperature–pressure curves for crystalline polymers have also been studied for branched polyethylene, polypropylene (PP), and poly(1‐butene) …”

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Impact of compression molding conditions on the thermal and mechanical properties of polyethylene

Shamloo

Fathi

Elkoun

et al. 2017

J of Applied Polymer Sci

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Compression molding is a current technique in polymer processing. Despite numerous studies, effect of molding pressure on physical properties has surprisingly not been fully investigated. In this study, the thermal and mechanical behavior of the compression-molded polyethylene were thus explored to better grasp the relationship between processing parameters and ensuing properties. The effect of the molding temperature, pressure, cooling rate, and temperature profile on the tensile and flexural moduli as well as melting point of polyethylene was studied. We conclude that higher tensile and flexural moduli are obtained by increasing pressure and molding temperature, as well as decreasing the cooling rate. Our results were corroborated by X-ray diffraction and differential scanning calorimetry measurements. Moreover, the use of a temperature gradient with different temperatures for the upper and bottom plates of the mold leads to asymmetric samples whose tensile and flexural moduli are improved. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46176.

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“…In the polymer-polymer mixture, for example, the PE/polypropylene blend, the DT A melting curve of PE showed three endothermic peaks, as in the melting of pure PE at high pressure, and the melting peaks shifted to the low temperature side with decreasing PE content. 8 The high pressure crystallization of pure PE produced ECC which melted at about 142°C at 1 atm as shown in Figure 7(a). The DTA melting curve at 1 atm of the binary mixture ( WPE = 0.8) crystallized at 460 MPa showed two peaks due to the melting of PE (high temperature peak) and the eutectic melting as shown in Figure 7(b).…”

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Melting and Crystallization of a Pseudo-Binary Mixture of Polyethylene and 1,2,4,5-Tetrachlorobenzene under High Pressure

Nakafuku

1985

Polym J

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ABSTRACT:High pressure differential thermal analysis (DT A) was performed for a pseudobinary mixture of polyethylene (PE) and 1,2,4,5-tetrachlorobenzene crystallized at a cooling rate of about 5 K min -1 to study the change in melting temperature T m with pressure and composltlon ratio. The phase diagram of the eutectic binary mixture at elevated pressures up to 400 MPa was determined. In the hypereutectic region of the phase diagram of PE, two endothermic peaks appeared in the DT A curve of melting and approached each other with pressure. In the hypoeutectic region, the distance between the two melting peaks increased with pressure. The pressure dependence of the eutectic point at I atm was 0.33oC MPa -1 on the average for all compositions. The DT A curve of the binary mixture under high pressure above 350 MPa indicated that the high pressure phase usually appearing in pure PE does not appear in PE in the binary mixture. The DT A curve at I atm of a sample crystallized under high pressure suggests that the extended chain crystal (ECC), easily formed by melt crystallization of pure PE above 350 MPa, was formed only slightly in the mixture even at a PE content 90%. In recent years, many papers on the compatibility or solubility of polymer-polymer mixtures have been published, but only a few have dealt with eutectic binary mixtures contammg crystalline polymers. Smith and Pennings 1 -3 reported that polyethylene (PE) and 1,2,4,5-tetrach1orobenzene (1 ,2,4,5-TCB) pseudo binary mixture solidifies in eutectic form by melt-crystallization at an appropriate cooling rate at atmospheric pressure. They pointed out that the eutectic temperature and composition of the binary mixture depends significantly on the kinetic factors governing the crystallization of polymers. For samples quenched to 81 oc from the melt, the eutectic temperature is 115°C and the eutectic composition for the polymer volume fraction is 0.79. 3 pure PE under high pressure have been studied by many investigators. The average pressure dependence of the melting temperature of PE at 1 atm is 0.28°C MPa -1 . 4 Above 350 MPa, a phase transition from orthorhombic to the hexagonal phase (high pressure phase) occurs. Furthermore, the so called extended chain crystal (ECC) is formed by melt-crystallization of pure PE under high pressure.The melting and crystallization behavior of This paper reports the melting phase diagram of a PE/1,2,4,5-TCB pseudo binary mixture under high pressures up to 400 MPa. Differential thermal analysis (DT A) was carried out under high pressure for the binary mixture. Pressure dependence of the eutectic temperature was determined. The effect of 1,2,4,5-TCB on the phase transition of PE under high pressure was also investigated. The melting behavior of the high pressure crystal-869

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Effects of Blending on the Melting and Crystallization of Polyethylene ahd Polypropylene under High Pressure

Cited by 7 publications

References 14 publications

Melting parameters of poly(glycolic acid)

Melting parameters of poly(glycolic acid)

Impact of compression molding conditions on the thermal and mechanical properties of polyethylene

Melting and Crystallization of a Pseudo-Binary Mixture of Polyethylene and 1,2,4,5-Tetrachlorobenzene under High Pressure

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