Based on the crystallographic data in Table $13\mathrm{.}2,$ calculate the density of crystalline PTFE

$($I$)$ and iPS.

TABLE $13\mathrm{.}2$

Unit Cell Parameters for Several Polymers

Note: Asterisks in column $4$ denote the chain axis.

Source: From B$.$ Wunderlich, in Macromolecular Physics, Vol. I: Crystal Structure, Morphology, Defects, Academic Press,

New York, $1973.$