  The structural properties of a linear polymer and its evolution in time have
a strong bearing on its anisotropic stress response. The mean-square bond
length and mean bond angle are the critical parameters that influence the
time-varying stress developed in the polymer. The bond length distribution
along the chain is uniform without any abrupt changes at the ends. Among the
externally set parameters such as density, temperature, strain rate, and chain
length, the density as well as the chain length of the polymer have a
significant effect on the stress. At high density values, changes in
mean-square bond length dominates over changes in radius of gyration and
end-to-end length. In other words, bond deformations dominate as opposed to
changes in size and shape. Also, there is a large change in the mean-square
bond length that is reflected as a jump in the stress. Beyond a particular
value of the chain length, $n = 50$, called the entanglement length,
stress-response is found to have distinctly different behavior which we
attribute to the entanglement effects. Short chain polymers more or less behave
like rigid molecules. There is no significant change in their internal
structure when loaded. Further, temperature and rate of loading have a very
mild effect on the stress. Besides these new results, we can now explain well
known polymeric mechanical behavior under dynamic loading from the point of
view of the evolution of the molecular dynamics and the derived structural
properties. This could possibly lead to polymer synthesis with desired
mechanical behavior.
