Structure and properties of commercial fluoroplast films

It was found that on cutting thin non-oriented PTFE films their dynamic modulus reduces. This is related to loosening of the molecular packing opening the way to more intense thermal generation of conformational defects. During orientation reduction of the size of the crystallites and rise in the paracrystallinity factor are noted. Inversion of the temperature dependence of the dynamic modulus is linked to the influence of the interlamellar shear strains. It is shown that the transparency of the films is determined by the size of the fluctuations of orientation both of the crystallites and larger structural elements.