Improving visible-light transparency of drawn melt-crystallized linear polyethylenes: influence of molecular weight distribution

A series of drawn melt-crystallized linear polyethylenes (LPEs) with different molecular weight distributions (MWD = M_w/M_n) ranging from 2 to 25 are investigated with respect to the visible-light transparency. The results indicate that the MWD of the LPEs significantly influences the visible-light transparency of drawn melt-crystallized LPEs. At a high MWD, drawn melt-crystallized LPEs films are transparent and glass-like, this in contrast to the LPEs with a low MWD. A mechanism behind the observed results is proposed based on differential scanning calorimetry (DSC) analysis, small-angle X-ray scattering, wide-angle X-ray scattering, and small-angle light scattering experiments. A correlation between the molecular characteristics, especially the MWD, and the visible-light transparency of the drawn melt-crystallized LPEs is proposed. (Figure presented.).