Temperature-dependent three-dimensional small-angle scattering in semicrystalline polymers

Processes for forming products from synthetic polymers often yield materials whose morphology is of low (orthorhombic, monoclinic, etc) symmetry. Characterizing such morphology by means of small-angle scattering (SAS) requires the mapping of the full three-dimensional scattering pattern from such materials. This requires special protocols in SAXS (small-angle X-ray scattering) or SANS (small-angle neutron scattering) experiments. SAS patterns from such experiments usually contain contributions from more than one scattering mechanism. In the case of semicrystalline polymers we have found that recording SAS patterns as a function of temperature allows the analyst to separate contributions arising from the two-phase morphology from those attributable to other effects such as voids and long-range molecular correlations. The synchrotron SAXS observations presented here extend our previous analysis of temperature-induced contrast variation in two-dimensional SAS patterns to two interesting three-dimensional cases.