A composite article includes a substrate and a pressure sensitive adhesive (PSA) disposed on the substrate. The PSA includes a polymer formed from at least one radical curable organic compound polymerized in the presence of an organoborane initiator. The polymer has a polydispersity index of less than or equal to 5.0 and a temperature of softening less than a temperature of use. The composite article is formed by a method including the steps of polymerizing the at least one radical curable organic compound to form the polymer and applying the PSA to the substrate to form the composite article. The polymer is formed by a method including the steps of combining the at least one radical curable organic compound and the organoborane initiator and polymerizing the at least one radical curable organic compound.