Study of the structure of oriented blends of polypropylene and polyethylene obtained by the method of polymerization in situ combination

Попов, В. П.; Антипов, Е. М.; Kuptsov, S. A.; Kuz'min, N. N.; Bezruk, L.I.; Frenkel, S.Ya.

doi:10.1002/actp.1985.010360302

Cited by 17 publications

(3 citation statements)

References 3 publications

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“…Polyethylene, being an organic flexible-chain polymer, does not form a mesophase spontaneously when heated. To induce LC ordering, it is necessary to have a mechanical field retaining the chain in an unfold state above the melting point [19,20]. However, a thermodynamically stable existence of the mesomorphous state of the condis-crystalline (or condis-mesophase) type in the temperature range 303-600 K was found in polytetrafluoroethylenes which, as distinct from polyethylene, have carbon atoms framed with fluorine instead of hydrogen atoms [21].…”

Section: Thermodynamics and Structure Of Polyorganophosphazenesmentioning

confidence: 99%

Mesophase State of Polyorganophosphazenes

Kulichikhin¹,

Антипов²,

Borisenkova³

et al. 1994

Partially Ordered Systems

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Earlier it was believed [1] that an ordering at a level exceeding the shortrange order of low molecular liquids cannot exist above the melting point in flexible-chain polymers which do not contain meso genic groups. However, recently, a large number of polymers, for example, polyphosphazene, has been found, which cannot be described in the framework of the traditional classification of liquid crystals. An additional type of mesomorphic state, that of a conformationally disordered crystal, was suggested [2,3].A more common approach is analyzing this type of mesophase as a threedimensional ordered crystal having a different perfection extent along each of its crystallographic dimensions. In order to gain a better insight into this problem, it is necessary to accumulate experimental evidence.Polyorganophosphazenes (PPh) with the following general formula:are of interest from the viewpoint of the meso phase class of polymers [4], since many of the representatives of this class may have an ordering level intermediate between a crystalline and an amorphous state in a broad temperature range [5]. A comprehensive review of earlier works on the structure and properties of PPh was published in [6]. The number of publications on the description of the structure, morphology, and characteristics of the physical transitions and physical-mechanical properties of these polymers has considerably increased in recent years. However, there is no complete information on the structure of PPh, especially in the mesomorphous state. V. P. Shibaev et al. (eds.), Liquid Crystalline and Mesomorphic Polymers

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Section: Thermodynamics and Structure Of Polyorganophosphazenesmentioning

confidence: 99%

Mesophase State of Polyorganophosphazenes

Kulichikhin¹,

Антипов²,

Borisenkova³

et al. 1994

Partially Ordered Systems

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“…or conformationally different from both the crystalline and the disordered amorphous phases, and its role in crystallization/melting and mechanical relaxation processes have been the subject of discussion for some decades already [2,3,5,7,[9][10][11][12][13][14]. Three (the high temperature α-relaxation and the low-temperature β-and γ-relaxation) relaxation processes lying below the melting temperature T m , and another thermal transition (termed λ) just above T m , i.e.…”

Section: Introductionmentioning

confidence: 99%

“…This intermediate phase is also referred to as mesophase, interfacial or rigid amorphous phase [5]. A series of studies [13,14] showed that the melting/crystallization processes in flexible-chain polymers are actually more complicated than originally thought. X-ray diffraction measurements revealed that during heating, the crystalline phase of PE first transforms into a liquid crystal state and then into the true isotropic melt.…”

Section: Introductionmentioning

confidence: 99%

Sensitive temperature-dependent phase resolution of polyethylene-clay nanocomposites

Sagitova¹,

Donfack²,

Prokhorov³

et al. 2022

Laser Phys.

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With the help of spectroscopic and differential scanning calorimetry (DSC) techniques, we have studied conformational and phase reorganizations as function of temperature in intercalated polymer-clay nanocomposites based on low-, middle-, and high-density polyethylene (PE) matrices. We show that Raman spectroscopy is sensitive to structural changes appearing during heating at much lower temperatures (about 47 °C) in comparison to DSC measurements. In fact, in the melting region where DSC traces show endotherms, Raman spectra reveal dramatic changes in the phase and conformational compositions of PE and PE-matrices within PE-clay nanocomposites. Noteworthy, the structural reorganization pathway, through which the semicrystalline nanocomposites transform into a melt state, depends primarily on the PE density and weakly on the filler (nanoclay). Moreover, the temperature-dependent crystallinity degree and the total amount of trans-conformers of the PE system are determined, and the evidence for the formation of intermediate crystal-like phase during heating is shown.

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Mesophase structure of flexible‐chain polymers

Антипов

Kuptsov

Куличихин

et al. 1989

Makromolekulare Chemie. Macromolecular Symposia

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Astructure a?polyethylene(PE)and polycbis(2, 2,2-trifluoroethoxy)phosphazene] (PPh)haa been studied by means of the X-ray diffraction technique, scanning electron microscopy and differential scanning calorimetry. The polymers under investigation are examples of the organic and inorganic mesophase flexible-chain polymersnotcontaining the mesogenic groups. Whenheated above the melting point both polymers form the condis crystal mesophase state which is stable in a wide temperature range. The PE mesophase reveals the pseudohexagonal structure, while the structure of mesophase PPh has some peculiarities arising from the sharp increase in the chain stiffness within a certain temperature range. The PPh mesophase structure is characterized by the perfect one-dimensional long--range order of the monomolecular layers and by the short-range order Only along the two other directions within the layer. This structure may be due to the difference between the interactions of the inorganic backbones and regularly alternating side trifluoroethoxy groups.

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Study of the structure of oriented blends of polypropylene and polyethylene obtained by the method of polymerization in situ combination

Cited by 17 publications

References 3 publications

Mesophase State of Polyorganophosphazenes

Mesophase State of Polyorganophosphazenes

Sensitive temperature-dependent phase resolution of polyethylene-clay nanocomposites

Mesophase structure of flexible‐chain polymers

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