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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2009-8-6
pubmed:abstractText
The melt rheology of four hyperbranched polymer structures with different molecular weights has been studied using nonequilibrium molecular dynamics (NEMD). Systems were simulated over a wide range of strain rates to capture the crossover behavior from Newtonian to non-Newtonian regimes. Rheological properties including shear viscosity and first and second normal stress coefficients were computed and the transition to shear thinning was observed at different strain rates for hyperbranched polymers of different sizes. The results were consistent with previous findings from NEMD simulation of linear and dendritic polymers. Flow birefringence was characterized by taking into account both form and intrinsic birefringences, which result from molecular and bond alignment, respectively. The stress optical rule was tested and shown to be valid only in the Newtonian regime and violated in the strong flow regime where the rule does not take into account flow-induced changes of the microstructure.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jul
pubmed:issn
1089-7690
pubmed:author
pubmed:issnType
Electronic
pubmed:day
28
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
044902
pubmed:year
2009
pubmed:articleTitle
Rheology of hyperbranched polymer melts undergoing planar Couette flow.
pubmed:affiliation
Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia.
pubmed:publicationType
Journal Article