Structure characterization of copolymers of ethylene and 1‐octadecene

Pérez, Ernesto; Benavente, Rosario; Quijada, Raúl; Narváez, Ana; Galland, Griselda B.

doi:10.1002/(sici)1099-0488(20000601)38:11<1440::aid-polb40>3.3.co;2-f

Cited by 19 publications

(28 citation statements)

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“…This indicates fundamental differences in the crystalline structure. This structure was discussed by Pérez et al [43], who found very similar DSC-traces for their sample. Based on their results, they concluded that the octadecene sidechains do not crystallize themselves separately, which is in accordance with Piel et al [16], who didn't find side-chain crystallization by DMTA.…”

Section: Dscsupporting

confidence: 62%

“…The SEC-MALLS-data of both materials show no deviation from the linear reference within the accuracy of the experiment, which points to the fact that neither material contains any long-chain branching (see Ref. [43] for an in-depth discussion of the question of how long-chain branching can be detected in PE). Table 1 shows the molecular characteristics of the samples characterized.…”

Section: Rheologymentioning

confidence: 63%

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Evidence of intra-chain phase separation in molten short-chain branched polyethylene

Stadler¹

2011

Express Polym. Lett.

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Abstract. Intramolecular phase separation is usually associated with block-copolymers, but the same phenomenon is also obtainable by random-copolymers. In this article, evidence of intramolecular phase separation is reported for a linear octadecene-ethene copolymer, which shows an evolving 'yield point' at a long time and low frequency. This is attributed to a partial phase separation of the long short-chain branches. In creep recovery, this behavior is evident as increasing elastic steady-state creep recovery compliance J e 0 . In contrast to 'normal' block-copolymers, this special polymer has an increase in phase separation with temperature, which is caused by the chemical composition and the short chain segments in the side chain domain, leading to a high surface fraction. Vol.5, No.4 (2011) 327-341 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2011 * Corresponding author, e-mail: fjstadler@jbnu.ac.kr © BME-PT length in their paper, as it cannot be determined due to the synthesis method. Such block-copolymers are usually thermorheologically complex [9,14,15]. The group of Bates [9,10], for example, found that below the order-disorder transition temperature, i.e., in the ordered state, the sample behaves like a gel and thermorheologically simple, while in the disordered state, a clear thermorheological complexity is found. The higher the temperature, the less pronounced the long-term relaxation process and, thus, the more similar is the data to a single-phase polymer melt. Recently, it was also proven that pure ethylene-/!-olefin copolymers with very long comonomers (C26) can be phase separating in the solid state, if their comonomer content is sufficiently high [16]. This effect is different from the previous cases, because it only involves one type of chain and, furthermore, occurs on random copolymers. Hence, it is an effect that occurs only on a short length scale, as shown by the fact that the length of the comonomers used were 18 and 26 carbons. Thus, the second phase has to encompass only the maximum of 24 terminal carbons; realistically, 16-20 carbons. This effect had a small trace in X-ray diffraction, which points to a weak side chain crystallization [17,18]. However, it was shown that the samples showing this phase behavior in the solid state [16] did not show it in the melt state, as the samples behaved like normal linear low density polyethylenes (LLDPEs), being only special because of their higher flow activation energy E a , which is the consequence of the side-chain content s c of the comonomer [19,20]. Phase separation in the melt is usually visible by traces of the interfacial tension [21] and different temperature dependencies of the individual blend components and the interfacial processes [22,23]. Hence, if other techniques don't show any trace, e.g., because of too low differences in the electron density in X-ray scattering, rheological behavior can provide a valuable aid to the characterization of phase separation. Recently, molecular dynamics studies revea...

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Section: Dscsupporting

confidence: 62%

Section: Rheologymentioning

confidence: 63%

Evidence of intra-chain phase separation in molten short-chain branched polyethylene

Stadler¹

2011

Express Polym. Lett.

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“…The crystallinity from Raman spectra has been determined following two different protocols: the classical 14,15 and the new one 16,17 in which the band at 1065 cm −1 is considered with a normalization constant of 0.80. The difference between both of protocols comes from the interpretation of a third component within the structure.…”

Section: A Crystalline Structurementioning

confidence: 99%

Influence of thermal history on morphology and viscoelastic behavior of ethylene–1-octene copolymers synthesized with metallocene catalysts

2001

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The relationships among structure and properties have been established in copolymers of ethylene and 1-octene, synthesized by a particular metallocene catalyst system. The most important factor affecting the structure and properties of these copolymers is, evidently, the comonomer content. However, the cooling treatment from the melt has been found to be also a very significant factor and, although its influence on the thermal properties is rather small, some structural parameters and the viscoelastic behavior are clearly dependent upon thermal history. These parameters include the degree of crystallinity, lattice constants, relaxation processes, stiffness, and microhardness of the samples. Regarding the viscoelastic behavior, the ␤ relaxation is shifted to lower temperatures and its intensity is increased as 1-octene content raises. On the other hand, the ␣ mechanism, associated with motions within the crystalline regions, is also moved to lower temperatures. Such a relaxation is only observed up to a certain 1-octene content in the copolymer.

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“…The XRD patterns proposed by Perez et al [35] showed that there were two peaks at about 2y ¼ 19.8 and 21.48 for pure POE. The peak (2y ¼ 21.48) reflects the characteristics of the orthorhombic cell of polyethylene (PE) and the peak (2y ¼ 19.88) could be considered as indicatives of the side branches of octene in the crystalline structure.…”

Section: Xrdmentioning

confidence: 96%

Preparation of Poly(ethylene‐octene) Elastomer/Clay/Wood Flour Nanocomposites by a Melting Method

Liao

2005

Macro Materials & Eng

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Summary: The new nanocomposites consisting of metallocene poly(ethylene‐octene) (POE), silicate clay and wood flour (WF) were prepared by means of a melt blending method. In addition, maleic anhydride grafted poly(ethylene‐octene) (POE‐g‐MAH) was studied as an alternative to POE. The samples were characterized by XRD, FT‐IR spectroscopy, DSC, TGA, SEM, and mechanical testing. Based on the consideration of thermal and mechanical properties, it was found that the clay content of 11 wt.‐% was optimal for the preparation of POE‐g‐MAH/clay nanocomposites. The POE‐g‐MAH/clay/WF hybrid could obviously improve the mechanical properties of POE‐g‐MAH/WF hybrid since the former had the smaller WF phase size (being always less than 1.5 µm), the SiOC bond and the nanoscale dispersion of silicate layers in the polymer matrix. The biodegradation studies showed that the mass of hybrids reduced by about the content of WF. The new POE‐g‐MAH/clay/WF nanocomposites produced from our laboratory can provide a plateau tensile strength at break when the WF content was up to 50 wt.‐%.

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Structure characterization of copolymers of ethylene and 1‐octadecene

Cited by 19 publications

References 0 publications

Evidence of intra-chain phase separation in molten short-chain branched polyethylene

Evidence of intra-chain phase separation in molten short-chain branched polyethylene

Influence of thermal history on morphology and viscoelastic behavior of ethylene–1-octene copolymers synthesized with metallocene catalysts

Preparation of Poly(ethylene‐octene) Elastomer/Clay/Wood Flour Nanocomposites by a Melting Method

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