the present invention comprises reaction products resulting from the reaction of hydrazido - substituted or certain amino - substituted polymer stabilizers and cyclic dianhydrides , as well as the use of such products . the polymer stabilizers of the invention are useful for protecting a large variety of synthetic polymeric organic materials from the degradative effects of heat , light and oxygen . some of the modifiers are flame retardants and many are metal deactivators in addition to their primary activity .