Miscible polyolefin blends

A polyolefin blend having at least one melt-miscible polyolefin blend phase, the polyolefin blend comprising:

• a) a primary polyolefin selected from the group consisting of polypropylene and an ethylene/alpha-olefin copolymer having a defined segment length (SL-1) within a range of absolute value of from about 4.2 to about 8.8 Angstroms;
• and
• b) at least one modifying polyolefin comprising a block copolymer having two blocks, each block being a polymer of ethylene and one or more monomer units selected from the group consisting of propylene, 1-butene, butadiene, 1-pentene, 1-hexene, 1-octene, isoprene, 2-methyl-1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, and mixtures thereof,
• wherein each block of the modifying polyolefin has a weight average molecular weight of at least 20,000 daltons,
• and wherein the melt-miscible polyolefin blend phase comprises at least one block having a block segment length (SL-B) of from about 85% to about 115% of the SL-1,
• and further wherein the SL-1 range and the absolute value of SL-1 and SL-B are determined from an arbitrarily chosen common segment volume of 1.08.times.10.sup.-22 cubic centimeters.

A polyolefin blend having a melt-miscible polyolefin blend phase, the polyolefin blend comprising:

• a) a primary polyolefin selected from the group consisting of polypropylene and an ethylene/alpha-olefin copolymer having a segment length (SL-1) within a range of absolute value of from about 4.2 to about 8.8 Angstroms;
• and
• b) at least one modifying polyolefin comprising a block/segment copolymer comprising:
• i. a block being a polymer of ethylene and one or more monomer units selected from the group consisting of propylene, 1-butene, butadiene, 1-pentene, 1-hexene, 1-octene, isoprene, 2-methyl-1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, and mixtures thereof, and
• ii. at least one segment comprising a polar polymer having a weight average molecular weight of at least 1,000 daltons, the polar polymer segment derived from monomer units selected from the group consisting of styrene, substituted styrene, vinyl pyridine, N-vinyl pyrrolidone, a C.sub.1 -C.sub.8 alkyl acrylic ester, a C.sub.1 -C.sub.18 methacrylic ester, phenyl methacrylate, benzyl methacrylate, acrylonitrile, methacrylonitrile, and mixtures thereof;
• wherein the block has a segment length (SL-B) of from about 85% to about 115% of the SL-1, and wherein an absolute value of the SL-1 and the SL-B is determined from a chosen common segment volume of 1.08.times.10.sup.-22 cubic centimeters, and further wherein the block/segment copolymer has a weight average molecular weight of at least 20,000 daltons.