Rigid foam and associated article
A polyurethane or polyisocyanurate foam is prepared from a reaction mixture that includes comprising a polyol, an aromatic isocyanate compound, and a blowing agent. The polyol includes a poly(phenylene ether) having a number average molecular weight of 600 to 2000 atomic mass units and an average of 1.5 to 3 hydroxyl groups per molecule. The polyurethane or polyisocyanurate foam exhibits improved resistance to burning and/or reduced elapsed times to formation of tack-free foams relative to foams prepared without the poly(phenylene ether).