THE INTERPLAY BETWEEN POLYMER POLYDISPERSITY AND FILM GAUGE IN HDPE BARRIER FILMS: HOW POLYDISPERSITY CONTROLS THE GAUGE DEPENDENCE OF FILM BARRIER PROPERTIES

摘要

We studied the barrier properties of films produced from eleven different HDPE resins as a function of film thickness. The gauge-normalized water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) depend on film thickness for samples with a larger z-average molecular weight, and the gauge-normalized WVTR and OTR are independent of film thickness for samples with a smaller z-average molecular weight. We also find that WVTR tracks with the average degree of crystallinity of the film as determined by DSC, and that the dependence of film crystallinity on film thickness apparently accounts for the dependence of WVTR on film thickness.