Synthesis of new polymeric stabilizers for polymers

Abstract

A monomeric stabilizer (M), 2,2,6,6-tetramethyl-4-piperidinyl(6-methacryloyl amino)hexyl carbamate-1, was synthesized by a two-step controlled isocyanation in which methacrylic acid (MAA) reacted in the first step with hexamethylene diisocyanate (HMDI) at a 1:1 mol ratio to form an addition product containing one isocyanate group and one unsaturated double bond. In the second step, this product was reacted with 2,2,6,6-tetramethyl-4-piperidinol (TMP) in a 1:1 mol ratio at 80 °C in the presence of a catalyst dibutyltin dilaurate (DBTDL) to yield M. A new polymeric stabilizer, copolymer P1, was produced from M with methyl methacrylate (MMA) and another copolymer P2 was produced by reacting M with 2-hydroxy-4-benzophenonyl allyl carbamate (AI-DHBP). Azobisisobutylonitrile (AIBN) was used as an initiator. Their structures, thermal stability, extraction resistance, solubility in organic solvents, and stabilizing effectiveness against photooxidation and thermal oxidation of polypropylene (PP) were characterized by IR, NMR, TGA, and elemental analysis. The results show that both the monomeric and the polymeric stabilizers possess a stabilizing action for protecting PP against photooxidation and thermal oxidation.