Organic thermal stabilizers for rigid poly(vinyl chloride). Part XI: Anthraquinone derivatives

Anthraquinone and 1-aminoanthraquinone derivatives have been examined as thermal stabilizers or co-stabilizers for rigid PVC in air at 180 degrees C. Their high stabilizing efficiency is detected by their high induction period values (Ts) when compared with some of the common reference stabilizers used industrially such as dibasic lead carbonate, calcium-zinc soap and octyl tin mercaptide. Blending these organic stabilizers with some of the reference stabilizers in different ratios had synergistic effect on both the induction period and the dehydrochlorination rate. A probable mechanism for the stabilizing mode of these derivatives has been proposed, The stabilizing, efficiency is attributed partially to the stabilizers" ability to intervene in the radical chain degradation process of PVC and to the of the labile chlorine atoms on PVC chains by a relatively more stable moiety of the organic stabilizer. (c) 2005 Elsevier Ltd. All rights reserved.