Modification of Bismaleimide Resin by Poly(ethylene phthalate-co-ethylene terephthalate), Poly(ethylene phthalate-co-ethylene 4,4'-biphenyl dicarboxylate), and Poly(ethylene phthalate-co-ethylene 2,6-naphthalene dicarboxylate) Published online 12 June 2001/