Crystallization of polydisperse polyethylene fractionated according to pennings' method

Hert, Marius; Rault, J.; Robelin, E.

doi:10.1002/macp.1983.021840122

Cited by 6 publications

(3 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The C, value is usually lower than C,z (see for example [10,11,17]). This is due to the fact that C,1 is related to the alternate crystalline and amorphous regions and this value does not take into consideration the interspherulitic amorphous phase and the defects in crystalline lamellae.…”

Section: First Process Of Polymer Chain Scissionmentioning

confidence: 98%

Rate of thermooxidation and polymer morphology

Mucha¹

1986

Colloid & Polymer Sci

View full text Add to dashboard Cite

Abstracts: A model of the thermooxidation of semicrystalline polymers involving two processes simultaneously is described. The first process is initiated by oxygen dissolved in the interspherulitic amorphous pahse. The second is related to a slower rate of polymer chain scission in the interlamellar amorphous pahse, which is controlled by oxygen diffusion into the spherulite. The presented model describes an exampble of isotactic polypropylene and predicts the effect of polymer morphology on the process of thermooxidation. It leads to the conclusion that the initial rate of polymer chain scission depends on the amount of interspherulitic amorphous phase fraction but the slower rate, considered in steady state conditions of oxygen diffussion into the interlamellar amorphous phase, depends depends on spherulite size according to the derived equation.

show abstract

Section: First Process Of Polymer Chain Scissionmentioning

confidence: 98%

Rate of thermooxidation and polymer morphology

Mucha¹

1986

Colloid & Polymer Sci

View full text Add to dashboard Cite

show abstract

“…Eda et al We raise two questions: Why are the mobilities of the two kinds of peroxy radicals trapped in the crystalline sites different and why do the mobile peroxy radicals abstract hydrogen intermolecularly. 3 In order to answer these 0024-9297/85/2218-0170$01.50/0 questions, one must acquire a knowledge of the surrounding conditions of the peroxy radicals, for instance, the molecular orientations of the polymer chain and the conformational structures of the radicals.…”

Section: Introductionmentioning

confidence: 99%

Assessment of long branches in free radical polyethylene: correlation between the melt and solid states

Larbi¹,

Hert²,

Grenier³

et al. 1985

Macromolecules

Self Cite

View full text Add to dashboard Cite

factors, barring significant crystal packing forces, etc., we are (41) Natta, G.; Corradini, P.; Eassi, I. W. Nuouo Cimento, Suppl.confident that our calculations accurately represent the con-1960, 15, 68. See also ref 27. formational properties of polysilane and poly(dimethy1-(42) Atkins, E. D. T.; Keller, A.; Shapiro, J. s.; Lemstra, P. J. silylene). Polymer 1981, 22, 1161 and references therein.ABSTRACT A series of branched polyethylenes of the same apparent molecular weight have been characterized by gel permeation chromatography (GPC), viscometry, NMR, and SAXS. By use of these different techniques, the molecular weight distribution and the number of long branches have been determined. In these materials quenched from the melt, we show that the long period of the semicrystalline state and the dimensions of the coils in the melt before crystallization are correlated. These correlations permit verification of theories of Zimm and Stockmayer and Daoud and Joanny giving the conformations of the coils in the melt. Finally, we emphasize that the SAXS technique combined with GPC is an accurate method of asseeament of the number of branches, comparable to the 13C NMR technique and viscometry.

show abstract

“…In ref 1, the long periods of polydisperse polyethylene (PE) of various molecular weight distributions were measured. It has been shown that there is no general law between L and Mw but that for low molecular weight material, L can be expressed as a function of Afn according to the relation L s Afn1/2 for Afn < 105 (2) regardless of the value of Afw. In that case it can be concluded that the long period is given principally by the end-to-end distance r of the coils having the molecular weight Ain.…”

Section: Introductionmentioning

confidence: 99%

Relationship between the relaxation of polyethylene coils in the melt and the molecular weight distribution. 1. Crystallization measurements

Robelin-Souffaché¹,

Rault²

1984

Macromolecules

View full text Add to dashboard Cite

We have shown recently that the correlation between the semicrystalline state and the melt of polymers permits, by appropriate annealing and quenching experiments, measurement of the relaxation time of the polymer coils in the molten state. In this article we show that in polyethylene this time is given by the law r = Af"3, where Afn is the number-average molecular weight. This time is found to be of the order of magnitude of the stress relaxation time measured by de Vries and Tochon on similar samples and 3 orders of magnitude greater than the reptation time measured by Klein.

show abstract

Crystallization of polydisperse polyethylene fractionated according to pennings' method

Cited by 6 publications

References 16 publications

Rate of thermooxidation and polymer morphology

Rate of thermooxidation and polymer morphology

Assessment of long branches in free radical polyethylene: correlation between the melt and solid states

Relationship between the relaxation of polyethylene coils in the melt and the molecular weight distribution. 1. Crystallization measurements

Contact Info

Product

Resources

About