CRYSTALLIZATION OF POLY (ETHYLENE TEREPHTHALATE) IN ORGANIC SOLVENT

Abstract

The amorphous and undrawn poly (ethylene terephthalate) (PET) was treated with several kinds of organic solvents and silicon oil at temperatures of -10°C to 200°C, and the fine structure was investigated by means of X-ray diffraction (wide-angle and small-angle) and density gradient tube. The degree of swelling of PET treated with benzyl alcohol, benzene, tetrachloroethylene, and chloroform increased with the rise of treatment temperature. On the other hand, the degree of swelling of PET treated with dimethyl formamide (DMF), dimethyl acetoamide, and nitrobenzene at -10°C_??_75°C increased with a lowering of temperature. This unusual swelling behavior of PET was discussed on the basis of the interaction between PET and organic solvent. The degree of crystallinity of PET treated with organic solvent increased with the rise of temperature in every case. The crystallization was almost completed up to about 10°C in DMF and benzene. Acceleration of the crystallization in organic solvent may be attributed to the fact that the glass transition temperature of PET is lowered in organic solvent. The dominant selective uniplanar orientation of (100) plane was found for the PET which was treated with DMF in lower temperature.