STRUCTURES AND PROPERTIES OF INJECTION MOLDINGS OF CRYSTALLIZATION NUCLEATOR-ADDED POLYPROPYLENES .2. DISTRIBUTION OF HIGHER-ORDER STRUCTURES

Flexural test specimens were injection-molded from polypropylenes added with 0.5 wt % calcium carbonate, talc, p-tert-dibutyl-benzoic acid monohydroxy aluminum, or p-dimethyl-benzylidene sorbitol under cylinder temperatures of 200-320-degrees-C. Distributions in the flow direction of higher-order structures such as a*-axis-oriented component fraction [A*] and crystalline orientation functions and distributions in the thickness direction of higher-order structures such as crystallinity, beta-crystal content, the degree of b-axis orientation to the thickness direction, [A*], and crystalline orientation functions were studied. These higher-order structures are inhomogeneous in the flow and thickness directions, which strongly influences the product properties such as mechanical and thermal properties.