  We have used molecular dynamics to simulate an amorphous glassy polymer with
long chains to study deformation mechanism of crazing and associated void
statistics. The Van der Waals interactions and the entanglements between chains
constituting the polymer play a crucial role in crazing. Thus, we have
reconstructed two underlying weighted networks, namely, the Van der Waals
network and the Entanglement network from polymer configurations extracted from
the molecular dynamics simulation. Subsequently, we have performed
graph-theoretic analysis of the two reconstructed networks to reveal the role
played by them in crazing of polymers. Our analysis captured various stages of
crazing through specific trends in the network measures for Van der Waals
networks and entanglement networks. To further corroborate the effectiveness of
network analysis in unraveling the underlying physics of crazing in polymers,
we have contrasted the trends in network measures for Van der Waals networks
and entanglement networks in the light of stress-strain behaviour and voids
statistics during deformation. We find that Van der Waals network plays a
crucial role in craze initiation and growth. Although, the entanglement network
was found to maintain its structure during craze initiation stage, it was found
to progressively weaken and undergo dynamic changes during the hardening and
failure stages of crazing phenomena. Our work demonstrates the utility of
network theory in quantifying the underlying physics of polymer crazing and
widens the scope of applications of network science to characterization of
deformation mechanisms in diverse polymers.
