Structural changes in a uniaxially oriented copolymer of vinylidene fluoride and tetrafluoroethylene during strain

X-ray and spectroscopic methods have been employed to evaluate the structural changes during elastic loading of uniaxially extended films of the copolymer of vinyldene fluoride and tetrafluoroethylene. The rise found in the degree of crystallinity is linked with the processes of precrystallization of portions of the chains at the end surfaces of the β crystallites. The idea of a possible para-electric→ferro-electric transition during this loading is put forward.