Dispersions of olefin block copolymers

An article comprising:

• (A) a frothed foam produced from a dispersion comprising:
• a catalytic linear multi-block olefin interpolymer that is a linear ethylene/α-olefin multi-block copolymer with at least 50 mole percent ethylene and having a Mw/Mn from 1.7 to 3.5, a melting point, Tm, in degrees Celsius, and density, d, in grams/cubic centimeter, wherein
• Tm>−2002.9+4538.5(d)−2422.2(d)2;
• at least one dispersing agent comprising a polar polyolefin;
• wherein the catalytic linear multi-block olefin interpolymer comprises at least one hard segment and at least one soft segment;
• and
• the dispersion is dispersed in acrylonitrile monomer;
• (B) microcavities on at least one surface of the foam;
• and
• (C) the frothed foam has a compression set at 85° C., 20 minutes, at a pressure of 0.1 psig of less than 45 percent.