Crystalline organization in useful plastics

The size of the crystallites in nylon 66, polytetrafluoroethylene, and polyethylene correlates with the degree of crystallinity. This supports the suggestion that the amorphous content of partially crystallized polymers can be attributed to chain folds and other regions directly related to the crystalline structure, at least down to a level of 40–60% crystallinity. In all cases, the term “percent crystallinity” is a useful unifying concept expressing the over‐all degree of order including mesomorphic structures, the relative amounts of ordered and disordered material, and the quality of the ordered regions.