Statistical theory of the structure of amorphous regions in oriented partially crystalline polymers

An assumption is made according to which the microstructure of amorphous regions in oriented flexible-chain polymers relates to a local conformational free energy minimum. The amounts of regular and friable folds, loop chains and tie chains and their length distributions in the amorphous region have on the basis of this assumption been calculated in relation to the extent of this region and the degree of orientational stretching, taking account of the real density ratio for the crystalline and the amorphous regions and allowing for straightening (elongation) of the macromolecules due to stretching. Predictions of the model are in keeping with the available experimental data.