The free-radical copolymerization of difurylmethane with maleic anhydride

The copolymerization of difurylmethane with maleic anhydride in the presence of azobisisobutyronitrile as an initiator has been investigated at 65 °C, 72 °C and 85 °C in different solvents. Reaction feeds containing 85 mol % and higher of difurylmethane yielded a soluble alternating copolymer in which the furan residue entrained in the polymer chain formed 2,5 linkages and had 3,4 unsaturation. The 1:1 difurylmethane-maleic anhydride adduct was readily prepared, and at the above temperatures and in the presence of the radical initiator partially underwent retro-Diels-Alder reaction. Copolymerization of the difurylmethane and maleic anhydride thus formed yielded the unsaturated alternating copolymer. Copolymers prepared from reaction feeds with proportions of difurylmethane lower than 85 mol % had higher cross-link density and exhibited higher thermodecomposition temperatures.