Sorbitol derivatives as nucleators and clarifiers for polyolefins, and polyolefin compositions obtained therewith

A polyolefin composition consisting essentially of at least semi-crystalline to crystalline one homopolymer or copolymer of a C.sub.2 to C.sub.8 alpha-monoolefin and about 0.05 to about 2.5% by weight, of said composition of a D-sorbitol derivative of the following formula:

• ##STR9## wherein:
• (a) R and R.sup.1 are the same and represent a member selected from the group consisting of ##STR10## wherein R.sup.2 is mono-, di- or tri-substituted on the ring and represents a member selected from the class consisting of NO.sub.2 and CN;
• and wherein R.sup.4 is mono-, di-, or tri-substituted on the ring and represents a member selected from the class consisting of C.sub.1 -C.sub.6 alkyl or O-alkyl, and NO.sub.2 ;
• or
• (b) R and R.sup.1 are different and one of R and R.sup.1 is ##STR11## wherein R.sup.5 represents a member selected from the class consisting of H, C.sub.1 -C.sub.6 alkyl, NO.sub.2, Cl, Br and F, and the other of R and R.sup.1 is ##STR12## wherein R.sup.6 is mono-, di-, or tri-substituted on the ring and represents a member selected from the class consisting of alkyl or O-alkyl groups having 1 to 8 carbon atoms, NO.sub.2, CN and COOY, wherein Y is an alkyl having 1 to 8 carbon atoms;
• or
• (c) R and R.sup.1 are different and R is ##STR13## wherein R.sup.6 is as defined above, and R.sup.1 is ##STR14## wherein R.sup.3 is mono-, di-, or tri-substituted on the ring and represents an alkyl group having 4 to 6 carbon atoms.