Thermal and photostabilization behaviour of a novel naphthalene-HALS derivative in HDPE and PP films

A novel N-[-8-(2-naphthoxy)Octyl]-4-amino,2,2, 6,6-tetramethylpiperidine st abiliser has been synthesised and characterised and its thermal and photost abilising performance examined in both high density polyethylene and polypr opylene films. Its performance has been compared with that of a commercial hindered piperidine light stabiliser, Tinuvin 770 together with the effects of naphthalene. Using FTIR analysis, the naphthoxy-HALS showed excellent p roperties as a thermal and photostabiliser, showing strong autosynergism in the former case. Comparisons with Tinuvin 770, showed that the naphthaleni c moiety of the molecule plays a role in the thermal stabilization process by scavenging oxygen. Naphthalene itself exhibited some degree of thermal s tabilization and reversed its behaviour from being a weak stabilizer at low concentrations to a prooxidant at higher concentrations. The same pattern of stabilization was observed during the photoaging of polypropylene with t he exception of the mixture of Tinuvin 770 and naphthalene which was found to exhibit the best performance at the higher concentration. (C) 1999 Elsev ier Science Ltd. AU rights reserved.