A COMPARATIVE-STUDY OF MONOMER, HOMOPOLYMER AND COPOLYMER HALS

Six new HALS in the form of monomer, homopolymer and copolymer, based on 2,2,6,6-tetramethylpiperidinyl methacrylate and 2,2,6,6-tetramethyl piperidinyl 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 copolymeri c HALS, with piperidinyl carbamate monomer being the most effective. T he results also show that the extraction resistance of polymeric HALS against water or detergent-water solution at 90-degrees-C is very high , while that for monomeric HALS is poor. Thermal stability of polymeri c HALS is much higher than that of monomeric HALS. The different prope rties of polymeric and monomeric HALS are discussed. Based on UV-spect ra and ESR results, the photostabilizing mechanism of these HALS is pr oposed.