Investigation of the superstructure of polymers during deformation by synchrotron radiation

Firstly a short review of some frequently used models for fibre structures is given. Then a model, based on a three-dimensional monoclinic paracrystalline macrolattice is described. This model allows the calculation of the two-dimensional intensity distribution for the small-angle scattering from semicrystalline polymers with different orientational states. The parameters of the model result from comparison with the measured intensity. The method of analysis is applied to low-density polyethylene deformed uniaxially at different temperatures. The use of synchrotron radiation makes it possible to follow the destruction and rebuilding of the superstructure. A reversible change of the superstructure during stretching and relaxing was found for different draw ratios for very high-molecular-weight polyethylene samples.