JOURNAL OF POLYMER ENGINEERING

 Vol. 23, No. 6, 2003, page 437

A STUDY OF CHEMICAL AND PHYSICAL CHANGES DURING BIAXIALLY ORIENTED POLYPROPYLENE FILM PRODUCTION

 Semra Ülkü*, Devrim Balköse, Esen Arkış and Muzaffer Sipahioğlu

 İzmir Institute of Technology

Faculty of Engineering, Department of Chemical Engineering

Gülbahçeköyü Urla İzmir Turkey

 ABSTRACT

      Polypropylene films obtained during the biaxial orientation process were characterized by energy dispersive X-ray analysis (EDX), scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, infrared spectroscopy. Inorganic particles with Al, Si, Na, Mg, Ti, K,O elements were present in biaxially oriented films. Polypropylene had molecules with both isotactic configuration and it was crystallized only in isotactic α phase. The films drawn in one and two directions had unit cells with b axis parallel to surface of the films. The antioxidants present in the films were consumed during processing, preventing polypropylene oxidation in air at high processing temperatures. One surface of the films contained less polypropylene and had functional groups rich in oxygen such as C=O and COO^-.

 Key words: polypropylene, crystallinity, melting endotherm, crystallization, biaxial orientation

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