Biomedical subjects

Giuseppe Marrucci

Publications and source records attributed to Giuseppe Marrucci.

2 recordsLinked to original sources

PubMed2004

Highly entangled polymer primitive chain network simulations based on dynamic tube dilation.

The concept of dynamic tube dilation (DTD) is here used to formulate a new simulation scheme to obtain the linear viscoelastic response of long chains with a large number of entanglements. The new scheme is based on the primitive chain network model previously proposed by some of the authors, and successfully employed to simulate linear and nonlinear behavior of moderately entangled polymers. Scaling laws are generated by the DTD concept, and allow for prediction of the linear response of very long chains on the basis of suitable simulations performed on shorter ones, without introducing adjustable parameters. Tests of the method against existing data for linear monodisperse polyisoprene and polystyrene show good quantitative agreement.

Journal Article↗

PubMed2003

Flow-induced orientation and stretching of entangled polymers.

A single-mode constitutive equation is proposed which accounts, in a very simple way, for the most important feature of the molecular theory for entangled polymers based on the 'tube' concept, i.e. that the orientation of the tubes and the stretching of the chain within them relax over different time-scales. The much faster relaxation of stretch is essentially a Rouse process, whereas orientational relaxation takes place by a combination of several factors, including reptation, tube-length fluctuations and constraint release, both thermal and convective. The model presented here accounts for all of these mechanisms, albeit in a simplified way, with the exception of fluctuations, which cannot be dealt with in a single-mode theory. Extension to a multi-mode version should, however, be easy.

Models, Molecular↗