Rheology of polydisperse polymers: relationship between intermolecular interactions and molecular weight distribution

Cassagnau, Philippe; Montfort, J. P.; Marin, G.; Monge, Ph.

doi:10.1007/bf00366679

Cited by 71 publications

(58 citation statements)

References 30 publications

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“…The qualitative variations of the relaxation times are in agreement with the experimental observation on bidisperse samples [22] but also with the predictions of tube renewal. The shift in relaxation times together with the feature of double reptation of previous theories are retrieved but in a self-consistent way.…”

Section: Comparison With Double Reptation With Tube Renewal On Bidispsupporting

confidence: 85%

“…However, it has been asserted [11,[22][23][24][25] that the double reptation alone misses the dependence of relaxation times with respect to the MWD and especially it cannot take into account the change of the relaxation time of high molecular weight species in a composite surrounding though this effect becomes increasingly important for high polydispersity. The correct behaviour can be described by the introduction in the relaxation function of a relaxation time which depends on the molecular weight distribution.…”

Section: Introductionmentioning

confidence: 97%

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A modified tube dilatation theory for the relaxation of entangled linear polymer melts

Carrot

Majesté

2005

Journal of Non-Newtonian Fluid Mechanics

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Section: Comparison With Double Reptation With Tube Renewal On Bidispsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 97%

A modified tube dilatation theory for the relaxation of entangled linear polymer melts

Carrot

Majesté

2005

Journal of Non-Newtonian Fluid Mechanics

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“…For example, assuming that contour length fluctuations can be included in the reptative motions, Cassagnau et al 20) have successfully used this theory to calculate the dynamic moduli in the terminal zone for various commercial polymers. Peirotti et al 21) recently showed that chain reptation with contour length fluctuations and tube constraint release are the relevant mechanisms of chain relaxation, even though the polymer samples are nearly monodisperse.…”

Section: A Blend Relaxation Function Modelmentioning

confidence: 99%

Structure and dynamics of melt poly(ɛ-caprolactone) from inverse rheological calculation

Gimenez¹,

Cassagnau²,

Fulchiron³

et al. 2000

Macromol. Chem. Phys.

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IntroductionThe correlation of the flow curves of a melt polymer and its molecular weight distribution (MWD) has long been a subject of discussion. The first papers on the inverse problem were published by Tuminello 1) and Malkin et al. 2)Within the last ten years, the resolution of the inverse problem has been extensively treated because the forward problem of the calculation of the dynamic moduli has received interesting new developments from a molecular point of view. For example, the concept of double reptation proposed by Tsenoglou 3) and Des Cloizeaux 4) is now viewed as the reference model for the calculation of dynamic moduli from known MWDs.Two different approaches to the inverse solution were generally used. The first one tries to solve the ill-posed problem by using either a numerical algorithm based on a Tikhonov regularization procedure (Wasserman 5) , Leonardi et al. 6) ) or a regularization method using quadratic programming (Ramkumar and Wiest 7) ). Wasserman used various relaxation spectra with a mixing rule based on the double reptation concept, whereas Leonardi et al.6) used an empirical blending law on complex viscosities. This second method also uses numerical methods but these methods postulate the shape of the MWD, giving its analytical form as some typical shapes of the MWD which are generally assumed in the case of a particular polymerization process. Different works can be cited: Tuminello 1,8,9) , Malkin and Teishev 2) , Wood-Adams and Dealy 10) . Carrot and Guillet 11) proved that a reasonable solution to the inverse problem, i. e., the determination of the MWD from dynamics experiments in the linear viscoelastic domain, can be found using simple molecular dynamics together with additional information concerning the shape of the MWD. Full Paper:The linear viscoelastic behavior of poly(ecaprolactone) (PCL) in situ synthesized between the plates of the rheometer was investigated. The polymerization of e-caprolactone was initiated and catalyzed by titanium tetrapropoxide. These polymers are very sensitive to hydrolysis of the alkoxy-titanium bonds included in the polymer chains. Two different forms of PCL can be studied: hydrolyzed or non-hydrolyzed PCL. However, only the molecular weight distribution (MWD) of the hydrolyzed chains can be accessed from size exclusion chromatography (SEC) analysis. The MWD of the in-situ synthesized poly(e-caprolactone) was calculated by solving the inverse problem of determination of the MWD from rheological data. A continuous form of the relaxation function was derived and an a priori shape (Wesslau or bi-modal Wesslau ) of the MWD was assumed. Then MWDs calculated from complex moduli curves were used to investigate the structure of the poly(e-caprolactone) at the end of the polymerization process. About 85% of the polymer chains consist of a single branched linear structure. The remaining 15% are assumed to be mainly two fold branched. The presence of star structures cannot be precluded. The present work describes an illustrative example of the s...

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“…(4) and (12), where c is also rather small, approaching log T at small values of index i. These points are most representative of the convolution and the relations from w (log t) to G(t) and G c (t), which we show in Section 3.3 to be within the measurement error.…”

Section: Effective Distribution W (T) By the Characteristic Modelmentioning

confidence: 93%

Linear viscoelastic models

Borg¹,

Pääkkönen

2009

Journal of Non-Newtonian Fluid Mechanics

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Rheology of polydisperse polymers: relationship between intermolecular interactions and molecular weight distribution

Cited by 71 publications

References 30 publications

A modified tube dilatation theory for the relaxation of entangled linear polymer melts

A modified tube dilatation theory for the relaxation of entangled linear polymer melts

Structure and dynamics of melt poly(ɛ-caprolactone) from inverse rheological calculation

Linear viscoelastic models

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