| Abstract: | The Morphology of quenched poly(ethylene terephthalate) (PET) films crystallized by low-molecular-weight organic penetrants is studied by scanning electron microscopy. Films with thicknesses from ca. 1 mil (0.0025 cm) to ca. 35 mil (0.1 cm) were exposed to methylene chloride (MeCl2) and N,N-dimethylformamide (DMF) in the temperature ranges 0–38°C and 22–70°C, respectively. The effects on the surface and internal structures of contact with liquids and saturated vapors were examined. Severe porosity at the surface results from contact with the liquids, but only minor surface roughness appears following contact with vapors. Internal porosity developed in the thinnest films (ca. 1 mil) during crystallization in liquid environments. Here, the internal void fraction is greatest along the film centerline and decreases with increasing crystallization temperature. A mathematical model discussed previously accounts for the observed behavior. |
