disclosed are new compositions consisting of branched polyphosphonates and specific additive compositions that exhibit superior resistance to degradation due to exposure to air , high temperature , moisture or combinations thereof . also disclosed are polymer mixtures or blends comprising these branched polyphosphonates / additive compositions and commodity and engineering plastics and articles produced therefrom . further disclosed are articles of manufacture produced from these materials , such as fibers , films , coated substrates , moldings , foams , fiber - reinforced articles , or any combination thereof .