Elektronenbeugung

Hendus, H.

doi:10.1007/978-3-642-45971-9_32

Cited by 12 publications

(12 citation statements)

References 32 publications

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“…The values of a=, ab and ac for these samples are also given in this table. They also determined the degree of crystallinity from wide-angle X-ray diffraction measurements following the method of Hendus and Schnell [34]. The degree of crystallinity (1 -).…”

Section: Discussionmentioning

confidence: 99%

A Raman spectroscopic study of the morphological structure of the polyethylenes

Glotin

Mandelkern

1982

Colloid & Polymer Sci

182

107

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Abstract:The method described by Strobl and Hagedorn to analyze the Raman spectrum internal modes of semi-crystalline polyethylene has been applied to a set of selected polyethylene samples crystallized under controlled conditions. The crystallite structure can be described in terms of the relative amounts of the crystalline orthorhombic phase, the liquid-like amorphous phase and the interracial region. The dependence of the level of crystallinity on molecular weight and crystallization conditions is very similar to that found by other methods. However, this method allows for the quantitative determination of the interfacial content which becomes significant for molecular weights greater than about 1 • 10 5 for linear polyethylene fractions, and for all the branched samples and copolymers. The degree of crystallinity determined from density measurements is equal to the sum of the crystallinity and interfacial content obtained from the Raman analysis while enthalpy of fusion measurements yield values which are equal to just the crystallinity content. The difference between the level of crystallinity obtained from density and enthalpy of fusion is thus found to be primarily due to interfacial contributions.

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Section: Discussionmentioning

confidence: 99%

A Raman spectroscopic study of the morphological structure of the polyethylenes

Glotin

Mandelkern

1982

Colloid & Polymer Sci

182

107

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“…High reaction temperature favors chain-transfer reactions. For this reason the polyethylene waxes formed have many short-chain and only a few long-chain branches [142] and thus low densities. Higher-density waxes with lower degrees of branching are formed at lower reaction temperature.…”

Section: Productionmentioning

confidence: 99%

Waxes

Krendlinger¹,

Wolfmeier²,

Schmidt³

et al. 2015

Ullmann's Encyclopedia of Industrial Chemistry

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“…were 0c is the density of the crystalline phase and 0a = 0.86 g/cm 3 the density of the amorphous phase [7].…”

Section: Preparation Of Quenched Samples and Techniquesmentioning

confidence: 99%

Equilibrium and non-equilibrium melting of branched polyethylene relating to defect incorporation within crystals

Martínez‐Salazar

Cuesta

Calleja

1987

Colloid & Polymer Sci

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New equilibrium melting point data, for polyethylene containing chain defects, are tested in the light of random copolymer predictions. A simplified expression for the melting point depression of random copolymers containing small amounts of non-crystallizable units is derived. Non-equilibrium melting data for rapidly quenched polyethylene samples are also reported. The fusion enthalpy AH~ and the surface free energy oe for crystals containing defects are evaluated using crystallinity, equilibrium meltingtemperatures and X-ray long period data. It is shown that increasing defect penetration within crystals induces a decrease of AH~ with X in accordance with theoretical predictions. Finally oe is, similarly, shown to decrease with increasing number of chain defects attached to the crystal surface.

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Elektronenbeugung

Cited by 12 publications

References 32 publications

A Raman spectroscopic study of the morphological structure of the polyethylenes

A Raman spectroscopic study of the morphological structure of the polyethylenes

Waxes

Equilibrium and non-equilibrium melting of branched polyethylene relating to defect incorporation within crystals

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