NUCLEATION OF THE BETA-MODIFICIATION OF ISOTACTIC POLYPROPYLENE

The effects of the organic pigments C.I.P. RED 177 and C.I.P. Yellow 8 3 as nucleating agents on the crystallization of polypropylene were st udied by DSC. The anthraquinone pigment exerted a significant effect, resulting in structural modifications with lower melting point, and pa rticularly the beta-modification. The DSC curves exhibit four transiti on regions, with the following temperature intervals: I. 415-417 K, II . 423-425 K, III. 430-432 K and IV. 438-439 K. For evaluation of the b eta-nucleation effect of pigments, the ratio (Delta H-1 + Delta H-2)I( Delta H-3 + Delta H-4) was suggested.