(1-Methylethylidene)di-4,1-phenylene cyanate polymer with 1H, 3H-benzo -[1,2-c:4,5-c']difuran-1,3,5,7-tetrone and 2,2'-[(1-methylethylidene)bis -(4,1-phenyleneoxymethylene)]bis[oxirane]2-propenoate, hydrogen butanedioate