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Tesi etd-06302016-102913


Thesis type
Tesi di laurea magistrale
Author
CALONACI, NICOLA
URN
etd-06302016-102913
Title
Elasticity and yielding in model polymer glasses
Struttura
FISICA
Corso di studi
FISICA
Supervisors
relatore Prof. Leporini, Dino
Parole chiave
  • connectivity
  • polymers
  • glass transition
  • plasticity
  • elasticity
  • molecular dynamics
Data inizio appello
21/07/2016;
Consultabilità
Completa
Riassunto analitico
The goal of this thesis is to characterize the mechanical response to deforma-
tions of a coarse-grained polymer model in the glassy state. In particular, we want
to relate the mechanical behaviour to connectivity. To this aim MD simulations are
performed with systematic variation of bond length and chain stiffness, which are
the interaction parameters determining the connectivity of the model. Mechanical
deformation is simulated via the Athermal Quasi-Static (AQS) procedure at zero
temperature. We show that connectivity does not directly affect the elastic shear
modulus. However, since the latter depend on the morphology of the solid state, con-
nectivity still plays a role as it determines the solidification behaviour of the model.
In the plastic regime, we show that the stress at yielding depends on the connectivity-
related parameters of the model. Moreover, we find a correlation between the elastic
shear modulus and the stress at yielding, compatible with experimental data reported
in the literature.
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