Crystallization of Polymers from Solution under Shearing Stress II Polypropylene

Isotactic polypropylene was crystallized in the form of fibrous crystals from solution under shearing stress. The fibrous crystals consist of the oriented cluster of micro fibrils. From the electron microscopy and the electron diffraction study, it was found that the fine texture of this fibrous crystals is also the two component systems which are composed of the central threads with an extended chain character and the lamellae with a folded chain character deposited on the threads, as in polyethylene. Relatively larger lamellar structure than that of polyethylene was observed. The effect of crystallization conditions to the formation of the fibrous crystals from solution of isotactic polypropylene was described briefly. A characteristic melting behavior due to the melting of the central threads with an extended chain character was observed from the thermogram of differential scanning calorimeter.