SPHERULITE STRUCTURE OF ISOTACTIC POLYPROPYLENE BY ORIENTED CRYSTALLIZATION FROM MELTS

The method of oriented crystallization from the melt was applied to isotactic polypropylene and oriented specimens corresponding to radial fractions of single spherulites were obtained. The obtained texture of oriented β-phase and the texture of oriented α-phase corresponding to the negative spherulite and to the positive spherulite, respectively, were investigated by x-ray wide angle and small angle diffractions. From the former texture it has been shown that the negative spherulite has the polyethylenelike lamellar structure with uniaxial orientation. From the latter texture it has been shown that the complex orientation in the positive spherulite is consistent with the structure of thin layers with radial and branched lamellae reported by Padden and Keith. The cross-shaped pattern of x-ray small angle diffraction, probably characteristic of polypropylene positive spherulites, was explained from the standpoint of this structure. © 1968 Dr. Dietrich Steinkopff Verlag.