Non-Newtonian rheology of entangled polymer solutions and melts

Tsenoglou, C

dc.contributor.author	Tsenoglou, C	en
dc.date.accessioned	2014-03-01T01:16:48Z
dc.date.available	2014-03-01T01:16:48Z
dc.date.issued	2001	en
dc.identifier.issn	0024-9297	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14232
dc.subject	Polymer Solution	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Polymer relaxation	en
dc.subject.other	Mathematical models	en
dc.subject.other	Molecular weight	en
dc.subject.other	Non Newtonian flow	en
dc.subject.other	Rheology	en
dc.subject.other	Viscoelasticity	en
dc.subject.other	Viscosity	en
dc.subject.other	Organic polymers	en
dc.title	Non-Newtonian rheology of entangled polymer solutions and melts	en
heal.type	journalArticle	en
heal.identifier.primary	10.1021/ma0014665	en
heal.identifier.secondary	http://dx.doi.org/10.1021/ma0014665	en
heal.language	English	en
heal.publicationDate	2001	en
heal.abstract	Molecular theory based scaling arguments relating the extent of entanglement depletion to the prevailing flow intensity are utilized for the quantitative description of the shear thinning rheology of entangled linear polymer solutions and melts. A power law decay with respect to shear rate (gamma (over dot)) is assumed for the viscosity, eta similar to K gamma over dot(n-1), and the first normal stress coefficient, Psi (1) similar to L gamma over dot(m-2). Following experience and the Doi-Edwards molecular theory, the lower rate limit of the non-Newtonian regime is taken equal to the inverse of the relaxation time of the whole chain. By analogy, and consistent with Menezes and Graessley's model for polymer relaxation under fast flow, it is assumed that shear thinning ceases at a characteristic higher rate equal to the frequency of the swiftest entanglement renewal process. Within these two gamma (over dot) limits which define the non-Newtonian regime, estimates for the n and nz exponents are made connecting them to molecular relaxation characteristics. Expressions for the K and L coefficients are also derived, relating them to the molecular weight, chain rigidity, polymer concentration, and temperature.	en
heal.publisher	AMER CHEMICAL SOC	en
heal.journalName	Macromolecules	en
dc.identifier.doi	10.1021/ma0014665	en
dc.identifier.isi	ISI:000167615600018	en
dc.identifier.volume	34	en
dc.identifier.issue	7	en
dc.identifier.spage	2148	en
dc.identifier.epage	2155	en