  Thermal transport coefficient $\kappa$ is an important property that often
dictates broad applications of a polymeric material, while at the same time its
computation remains challenging. In particular, classical simulations
overestimate $\kappa$ than the experimentally measured $\kappa^{\rm exp}$ and
thus hinder their meaningful comparison. This is even when very careful
simulations are performed using the most accurate empirical potentials. A key
reason for such a discrepancy is because polymers have quantum--mechanical,
nuclear degrees--of--freedom whose contribution to the heat balance is
non--trivial. In this work, two semi--analytical approaches are considered to
accurately compute $\kappa$ by using the exact vibrational density of states
$g(\nu)$. The first approach is based within the framework of the minimum
thermal conductivity model, while the second uses computed quantum heat
capacity to scale $\kappa$. Computed $\kappa$ of a set of commodity polymers
compares quantitatively with $\kappa^{\rm exp}$.
