Synthesis of new polymeric stabilizers for polymers

A monomeric stabilizer (M), 2,2,6,6-tetramethyl-4-piperidinyl(6-methacryloy l amino)hexyl carbamate-l, was synthesized by a two-step controlled isocyan ation in which methacrylic acid (MAA) reacted in the first step with hexame thylene diisocyanate (HMDI) at a 1 : 1 mol ratio to form an addition produc t containing one isocyanate group and one unsaturated double bond. In the s econd step, this product was reacted with 2,2,6,6-tetramethyl-4-piperidinol (TMP) in a 1 : 1 mol ratio at 80 degrees C in the presence of a catalyst d ibutyltin dilaurate (DBTDL) to yield M. A new polymeric stabilizer, copolym er P1, was produced from M with methyl methacrylate (MMA) and another copol ymer P2 was produced by reacting M with 2-hydroxy-4-benzophenonyl allyl car bamate (AI-DHBP). Azobisisobutylonitrile (AIBN) was used as an initiator. T heir structures, thermal stability, extraction resistance, solubility in or ganic solvents, and stabilizing effectiveness against photooxidation and th ermal oxidation of polypropylene (PP) were characterized by IR, NMR, TGA, a nd elemental analysis. The results show that both the monomeric and the pol ymeric stabilizers possess a stabilizing action for protecting PP against p hotooxidation and thermal oxidation. (C) 2000 John Wiley & Sons, Inc.