Dynamic mechanical properties of homogeneous copolymers of ethylene and 1‐alkenes

Clas, S.‐D.; McFaddin, Douglas; Russell, K. E.

doi:10.1002/polb.1987.090250507

Cited by 52 publications

(36 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, it is possible that long branches can crystallize, forming crystallites with different sizes when compared with the main crystallizable chain. 17 In the case of ethylene/1-octadecene copolymers, several DSC thermograms exhibit the presence of more than one endotherm, indicating that the copolymers have more than one melting temperature (Table I). This behavior has been observed, especially for the copolymer with 5.1% of 1-octadecene and indicates the presence of crystals with different sizes.…”

Section: Methodsmentioning

confidence: 97%

“…[2][3][4] It is known that copolymers of ethylene and ␣-olefins with long chains, such as 1-octadecene, might show a different behavior from that usually found for ethylene/short ␣-olefins copolymers. 7,17 It is accepted that long branches may participate in the crystallization process, favoring the crystallinity. Also, it is possible that long branches can crystallize, forming crystallites with different sizes when compared with the main crystallizable chain.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Influence of the type and the comonomer contents on the mechanical behavior of ethylene/?-olefin copolymers

Simanke

Galland

Neto

et al. 1999

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

ABSTRACT:The influences of the type and concentration of ␣-olefin (1-hexene, 1-octene, 1-decene, 1-octadecene, 4-methyl-1-pentene) on the mechanical behavior and crystallinity degree of some ethylene/␣-olefin copolymers obtained by metallocene catalysts were studied by means of stress/strain experiments. The crystallinity degree of these copolymers has been determined by X-ray measurements. It has been observed that the copolymers show less resistance to strain as the comonomer content increases and the crystallinity decreases. Most of the studied copolymers exhibit a significant increase in the crystallinity level after the stress/strain experiments.

show abstract

Section: Methodsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Influence of the type and the comonomer contents on the mechanical behavior of ethylene/?-olefin copolymers

Simanke

Galland

Neto

et al. 1999

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

show abstract

“…Clas et al 17 observed also by DMA a deviating behavior between homogeneous ethene-butene, ethene-octene, and ethene-octadecene copolymers synthesized with vanadium catalysts: The intensity of the b transition increased with the comonomer content in 1-butene and 1-octene copolymers and also with the amount of interfacial material present. In ethene-1-octadecene copolymers, this intensity was comparatively low, even though there was about 20% interfacial material present.…”

Section: Dmamentioning

confidence: 98%

“…The influence of the structure and morphology on the dynamic mechanical behavior of PEs has been discussed in a number of publications, [11][12][13][14][15][16][17] An understanding of the principles involved is of value in predicting the response of these polymers in various product applications. In general, linear and branched PEs exhibit up to three transitions, which are labeled a, b, and c in order of decreasing temperature.…”

Section: Introductionmentioning

confidence: 99%

Thermal and mechanical analysis of metallocene‐catalyzed ethene–α‐olefin copolymers: The influence of the length and number of the crystallizing side chains

Piel

Starck

Seppälä

et al. 2006

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

Copolymers of ethene and 1-octene, 1-dodecene, 1-octadecene, and 1-hexacosene were carried out with [Ph 2 C(2,7-ditert BuFlu)(Cp)]ZrCl 2 /methylalumoxane as a catalyst to obtain short-chain branched polyethylenes with branch lengths of 6-26 carbon atoms. This catalyst provided high activity and a very good comonomer and hydrogen response. In this study, the influence of the length and number of the side chains on the mechanical properties of the materials was investigated. The crystalline methylene sequence lengths of the copolymers and lamellar thicknesses were calculated after the application of a differential scanning calorimetry/successive self-annealing separation technique. By dynamic mechanical analysis, the storage modulus as an indicator of the stiffness and the loss modulus as a measure of the effect of branching on the a and b relaxations were studied. The results were related to the measurements of the polymer density and tensile strength to determine the effect of longer side chains on the material properties. The hexacosene copolymers had side chains of 24 carbons and remarkable material properties very different from those of conventional linear low-density polyethylenes. The side chains of these copolymers crystallized with one another and not only parallel to the backbone lamellar layer, depending on the hexacosene concentration in the copolymer. The side chains crystallized even at low hexacosene concentrations in the copolymer. A transfer of these results to 16 carbons

show abstract

“…Three relaxation processes of PE have been extensively studied. [21][22][23] It is generally considered that the ␤ (ϳ Ϫ20°C) and ␥-transitions (ϳ Ϫ120°C) are due to the motion of branches 24 -27 and to the crankshaft motion of short polymer segments requiring a minimum of three methylene units 23,[27][28][29] in the amorphous matrix, respectively. In contrast, the ␣-transition (ϳ 45°C) is attributed to motions or deformations in the interfacial region (tie molecules loops, folds, etc.…”

Section: Ultradrawing Of Gel Films Of Uhmwpe and Lmwpe Blendsmentioning

confidence: 99%

Ultradrawing behavior of one- and two-stage drawn gel films of ultrahigh molecular weight polyethylene and low molecular weight polyethylene blends

Yeh

Chang

Yen

1998

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

ABSTRACT:The ultradrawing behavior of gel films of plain ultrahigh molecular weight polyethylene (UHMWPE) and UHMWPE/low molecular weight polyethylene (LMWPE) blends was investigated using one-and two-stage drawing processes. The drawability of these gel films were found to depend significantly on the temperatures used in the one-and two-stage drawing processes. The critical draw ratio ( c ) of each gel film prepared near its critical concentration was found to approach a maximum value, when the gel film was drawn at an ''optimum'' temperature ranging from 95 to 105°C. At each drawing temperature, the one-stage drawn gel films exhibited an abrupt change in their birefringence and thermal properties as their draw ratios reached about 40. In contrast, the critical draw ratios of the two-stage drawn gel films can be further improved to be higher than those of the corresponding single-stage drawn gel films, in which the two-stage drawn gel films were drawn at another ''optimum'' temperature in the second drawing stage after they had been drawn at 95°C to a draw ratio of 40 in the first drawing stage. These interesting phenomena were investigated in terms of the reduced viscosities of the solutions, thermal analysis, birefringence, and tensile properties of the drawn and undrawn gel films.

show abstract

Dynamic mechanical properties of homogeneous copolymers of ethylene and 1‐alkenes

Cited by 52 publications

References 18 publications

Influence of the type and the comonomer contents on the mechanical behavior of ethylene/?-olefin copolymers

Influence of the type and the comonomer contents on the mechanical behavior of ethylene/?-olefin copolymers

Thermal and mechanical analysis of metallocene‐catalyzed ethene–α‐olefin copolymers: The influence of the length and number of the crystallizing side chains

Ultradrawing behavior of one- and two-stage drawn gel films of ultrahigh molecular weight polyethylene and low molecular weight polyethylene blends

Contact Info

Product

Resources

About