a poly &# 34 ; for brevity ) main chain having terminal polysubstituted piperidinyl chain ends are novel compounds which have highly desirable uv - light stabilizing activity coupled with unexpectedly good thermal stability . these compounds , referred to as &# 34 ; piperidinyl - chain ended polys &# 34 ;, are oligomers which contain from 2 to about 18 aamid repeating units , for use in polymer recipes to formulate a stabilized polymeric composition comprising a uv - light - degradable organic polymer containing an effective amount of the poly sufficient to stabilize the polymer . a poly is especially effective in a polyolefin in which there is from about 0 . 1 percent by weight , to about 5 % by wt of the oligomer , and is also effective in a wide variety of pastel colored and / or transparent commercially significant polymers .