Structure evolution during film blowing:an experimental study using in-situ small angle x-ray scattering

The on-line morphological development during film blowing of 2 different linear low density polyethylenes (LLDPE) and a blend of LLDPE with low density polyethylene (LDPE) has been investigated, for the first time, using synchrotron Small Angle X-Ray Scattering (SAXS). The processing conditions, blow-up ratio and take-up ratio, have been varied and the resulting lamellar thickness, linear crystallinity and orientation evolution in machine direction is obtained from a detailed analysis of SAXS data. Ex-situ SAXS and wide angle X-ray Diffraction (WAXD) confirmed the effect of molecular structure and composition on structure evolution observed in the on-line experiments. The results obtained provide a valuable set of data for the understanding of the film blowing process and can be used to extend and improve numerical model