Thermal and viscoelastic behaviour of copolymers of propene and 1-hexene

Benavente, Rosario; Pereña, José M.; Bello, A.; Pérez, Ernesto; Locatelli, Paolo; Fan, Zhi-Quiang; Zucchi, Debora

doi:10.1007/bf00294914

Cited by 10 publications

(5 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The constancy of the enthalpy of melting with the cooling rate for VAE68 stands in contrast to the relatively big differences in the degree of crystallinity determined from the X-ray diffractograms. One of the reasons for this behavior is the progressive decrease of the crystal thickness as the cooling rate increases, leading to wider diffraction peaks and making more difficult the deconvolution between crystalline and amorphous components . An additional reason is the relative importance of the interfacial regions, , which may change in the different sample preparations and may be accounted for in a different manner when determining the X-ray crystallinity.…”

Section: Resultsmentioning

confidence: 99%

Wide-Angle X-ray Diffraction Study of the Phase Behavior of Vinyl Alcohol−Ethylene Copolymers

et al. 1998

Self Cite

View full text Add to dashboard Cite

The influence of the composition and thermal history on the type of lattice developed has been studied by wide-angle X-ray diffraction measurements in three vinyl alcohol-ethylene, VAE, copolymers with different compositions, which were crystallized from the melt at various cooling rates. The results are compared with those of the corresponding homopolymers, poly(vinyl alcohol) and lowdensity polyethylene. Both the composition and the cooling rate have been found to determine the crystalline structure of these VAE copolymers. Thus, for the samples slowly crystallized from the melt, a monoclinic lattice is obtained for copolymers VAE71 and VAE68 (with compositions of 71 and 68 mol % VA, respectively) while an orthorhombic lattice has been found for copolymer VAE56 (56 mol % VA). The effect of the cooling rate is very important, since copolymers VAE71 and VAE68 lead to the orthorhombic form when the samples are quenched from the melt. Copolymer VAE56 has been found to crystallize in an orthorhombic lattice under all the crystallization conditions here studied. The polymorphism exhibited by these copolymers is not the usual case for two different unit cells with welldefined lattice parameters: VAE71 and VAE68 show, by the influence of the cooling rate, a continuous change of some of the lattice constants. For instance, the angle β of the monoclinic lattice decreases smoothly from an "equilibrium" value of about 92.2°in the slowly crystallized samples to a final value in the quenched samples of 90°(orthorhombic unit cell). The degree of crystallinity determined from the X-ray diffraction patterns has been found to be in the quenched specimens considerably smaller than that in the slowly crystallized samples, standing in contrast to the constancy of the enthalpy of melting. Moreover, it seems that there are no differences in the melting temperatures between the two crystalline modifications.

show abstract

Section: Resultsmentioning

confidence: 99%

Wide-Angle X-ray Diffraction Study of the Phase Behavior of Vinyl Alcohol−Ethylene Copolymers

et al. 1998

Self Cite

View full text Add to dashboard Cite

show abstract

“…Very few properties have been measured, making it impossible to draw truly quantitative conclusions. Furthermore, since the four major studies on copolymers of propylene with 1-hexene, by Piloz et al [76,77], Arnold, Henschke, and Knorr [78], Benavente et al [79], and Ficker and Walker [80], gave conflicting results, it is even difficult to draw qualitative conclusions. A brief comparison of the key results of these studies will now be made.…”

Section: Isotactic Poly(propylene-co-i-hexene)mentioning

confidence: 97%

“…Consequently, we focus below mainly on these two studies. Benavente et al [79] and Ficker and Walker [80] also used traditional Ziegler-Natta catalysts, but they only reported results over limited composition ranges. Their results [79,80] over these narrow ranges were qualitatively similar to the results of Piloz et al [76,77], but it would be imprudent to extrapolate from them to try to reach conclusions over the full composition range.…”

Section: Isotactic Poly(propylene-co-i-hexene)mentioning

confidence: 97%

“…Among the higher a olefins, 1-hexene [76][77][78][79][80] has been studied most often as a comonomer in PP, although some work has also been reported for longer a olefins with an even number of carbon atoms [78] and for 1-pentene [81]. Very few properties have been measured, making it impossible to draw truly quantitative conclusions.…”

Section: Isotactic Poly(propylene-co-i-hexene)mentioning

confidence: 99%

See 1 more Smart Citation

Crystallization of Polypropylene and Poly(Ethylene Terephthalate)

Bicerano¹

1998

Journal of Macromolecular Science, Part C: Polymer Reviews

View full text Add to dashboard Cite

“…They are excluded from the crystal, due to their strong steric hindrance caused by molecular size, and incorporated in greater amount to the amorphous fraction. [22] Ethylene and 1-butene copolymers have been widely studied in the literature. It is not the case of the terpolymers, a family of polymers that has experimented an increasing interest 3 in recent years.…”

Section: Introductionmentioning

confidence: 99%

Influence of structure on the properties of polypropylene copolymers and terpolymers

et al. 2017

Self Cite

View full text Add to dashboard Cite

A set of Ziegler-Natta copolymers of iPP with ethylene or with 1-butene, and terpolymers with both counits have been characterized, devoting special attention to the effect of composition and processing conditions on the crystal structure and on the final properties.DSC and X-ray diffraction is used to study the polymorphism of copolymers and terpolymers.Comonomer insertion interrupts the isotactic sequences, acting as a structural defect, and the formation of  form is enhanced in the interval of studied compositions. Moreover, crystallinity decreases and crystal structure is modified. Comonomer type and concentration determine the extent of these modifications, resulting on important changes in macroscopicproperties. An important aspect to be considered is the higher ability of 1-butene units to be incorporated in the iPP crystals in relation to ethylene counits. From the balance of different properties, possible applications are suggested for the various types of samples. For instance, the excellent optical properties of the analyzed terpolymers make them very attractive for applications such as transparent film or packaging.

show abstract

Thermal and viscoelastic behaviour of copolymers of propene and 1-hexene

Cited by 10 publications

References 18 publications

Wide-Angle X-ray Diffraction Study of the Phase Behavior of Vinyl Alcohol−Ethylene Copolymers

Wide-Angle X-ray Diffraction Study of the Phase Behavior of Vinyl Alcohol−Ethylene Copolymers

Crystallization of Polypropylene and Poly(Ethylene Terephthalate)

Influence of structure on the properties of polypropylene copolymers and terpolymers

Contact Info

Product

Resources

About