Abstract
An assay on the thermal stability of isotactic polypropylene stabilized with Sanduvor PR 31, a hindered amine (O1-(1,2,2,4,6,6-hexamethyl-4-piperidyl) O3 - (1,2,2,6,6-pentamethyl-4-piperidyl) (2Z) – 2 - [(4-methoxyphenyl) methylene] propanedioate, was performed. The oxidability of modified polymer previously subjected to weathering treatment or UV irradiation was investigated in air by isothermal (1550C) and isobaric (normal pressure) oxygen uptake. The exposure time was sufficient enough to attend a slow degradation rate (281 days for weathering test and 550 h for accelerated UV ageing). The main kinetic parameters, oxidation induction time and oxidation rate, were determined from the dependencies of chemically consumed oxygen on testing time. Comparative results on reference samples (control or stabilized polypropylene) and degraded materials are analyzed for depicting the influence of ageing factors on the polypropylene durability. Keywords: polypropylene, UV degradation, weathering, oxygen uptake, Sanduvor PR 31