A comparative study of monomer, homopolymer and copolymer HALS

Abstract

Six new HALS in the form of monomer, homopolymer and copolymer, based on 2,2,6,6-tetramethylpiperidinyl methacrylate and 2,2,6,6-tetramethylpiperidinyl carbamate, have been prepared. A comparative study on them has been carried out using IR, NMR, TGA, VPO, UV-spectra and ESR. The results show that the photoprotecting effectiveness of monomeric HALS for polypropylene is higher than that of homopolymeric and copolymeric HALS, with piperidinyl carbamate monomer being the most effective. The results also show that the extraction resistance of polymeric HALS against water or detergent-water solution at 90°C is very high, while that for monomeric HALS is poor. Thermal stability of polymeric HALS is much higher than that of monomeric HALS. The different properties of polymeric and monomeric HALS are discussed. Based on UV-spectra and ESR results, the photostabilizing mechanism of these HALS is proposed. © 1994.