The study of structure and properties of polypropylene film for oil-filled cable

The relation of aggregates structure and morphology to the properties of polypropylene (PP) film used in polypropylene laminated paper (PPLP) for high-voltage oil-filled cable is studied. The interaction between PP film and oil is also investigated. It is shown that the aggregate structure parameters of PP film, such as crystallinity, orientation, and morphology (determined by infrared spectroscopy) agree with those obtained by the X-ray diffraction method. The key to improved breakdown strength, tensile strength and stability in oil for PP film is to increase the crystallinity, orientation, and molecular weight of PP film. The solubility of PP film in oil is related to its crystallinity, when the crystallinity of PP film is higher, its stability in oil is better.<>