Abstract: Low-density, thermoplastic foams comprising: (a) thermoplastic polymer cells comprising cell walls comprising polyethylene furanoate, wherein at least about 50% by volume of the cells are closed cells; and (b) at least HFO-1234ze(E) contained in said closed cells.

Abstract: A low-density, thermoplastic foam comprising: (a) thermoplastic polymer cells comprising cell walls forming closed cells, wherein said thermoplastic polymer comprises ethylene furanoate moieties and optionally ethylene terephthalate moieties, wherein said polymer comprises from about 1 mole % to about 100 mole % of ethylene furanoate moieties and optionally at least about 1 mole % ethylene terephthalate moieties; and (b) one or more HFOs having three or four carbon atoms and/or one or more HFCOs having three or four carbon atoms contained in the closed cells.